Patent Application
20190328299
The present invention also relates to the technical field of coated vessels and fabrication of coated vessels for storing biologically active compounds or blood. For example, the invention relates to a vessel processing system for coating of a vessel, to a portable vessel holder for a vessel processing system, to a plasma enhanced chemical vapor deposition apparatus for coating an interior surface of a vessel, to a method for coating an interior surface of a vessel, to a method for coating a vessel, and to a method of processing a vessel.
The present disclosure also relates to improved methods for processing vessels, for example multiple identical vessels used for venipuncture and other medical sample collection, pharmaceutical preparation storage and delivery, and other purposes. Such vessels are used in large numbers for these purposes, and must be relatively economical to manufacture and yet highly reliable in storage and use.
Prefilled syringes are commonly prepared and sold so the syringe does not need to be filled before use. The syringe can be prefilled with saline solution, a dye for injection, or a pharmaceutically active preparation, for some examples.
Commonly, the prefilled syringe is capped at the distal end, as with a cap, and is closed at the proximal end by its drawn plunger. The prefilled syringe can be wrapped in a sterile package before use. To use the prefilled syringe, the packaging and cap are removed, optionally a hypodermic needle or another delivery conduit is attached to the distal end of the barrel, the delivery conduit or syringe is moved to a use position (such as by inserting the hypodermic needle into a patient's blood vessel or into apparatus to be rinsed with the contents of the syringe), and the plunger is advanced in the barrel to inject the contents of the barrel.
One important consideration in manufacturing pre-filled syringes is that the contents of the syringe desirably will have a substantial shelf life, during which it is important to isolate the material filling the syringe from the barrel wall containing it, to avoid leaching material from the barrel into the prefilled contents or vice versa.
Since many of these vessels are inexpensive and used in large quantities, for certain applications it will be useful to reliably obtain the necessary shelf life without increasing the manufacturing cost to a prohibitive level. It is also desirable for certain applications to move away from glass vessels, which can break and are expensive to manufacture, in favor of plastic vessels which are rarely broken in normal use (and if broken do not form sharp shards from remnants of the vessel, like a glass tube would). Glass vessels have been favored because glass is more gas tight and inert to pre-filled contents than untreated plastics. Also, due to its traditional use, glass is well accepted, as it is known to be relatively innocuous when contacted with medical samples or pharmaceutical preparations and the like.
A further consideration when regarding syringes is to ensure that the plunger can move at a constant speed and with a constant force when it is pressed into the barrel. For this purpose, a lubricity layer, either on one or on both of the barrel and the plunger, is desirable.
An aspect of the invention is a syringe comprising a barrel defining a lumen and having an interior surface slidably receiving a plunger. The syringe barrel may be made of thermoplastic base material. A lubricity layer, characterized as defined in the Definition Section, is applied to, e.g., the barrel interior surface, the plunger, or both by PECVD. The lubricity layer may be made from an organosilicon precursor, and may be less than 1000 nm thick. A surface treatment is carried out on the lubricity layer in an amount effective to reduce leaching of the lubricity layer, the thermoplastic base material, or both into the lumen, i.e. effective to form a solute retainer on the surface. The lubricity layer and solute retainer are composed, and present in relative amounts, effective to provide a breakout force, plunger sliding force, or both that is less than the corresponding force required in the absence of the lubricity layer and solute retainer.
Another aspect of the invention is a method of plasma-enhanced chemical vapor deposition (PECVD) treatment of a first vessel, including several steps. A first vessel is provided having an open end, a closed end, and an interior surface. At least a first gripper is configured for selectively holding and releasing the closed end of the first vessel. The closed end of the first vessel is gripped with the first gripper and, using the first gripper, transported to the vicinity of a vessel holder configured for seating to the open end of the first vessel. The first gripper is then used to axially advance the first vessel and seat its open end on the vessel holder, establishing sealed communication between the vessel holder and the interior of the first vessel.
At least one gaseous reactant is introduced within the first vessel through the vessel holder. Plasma is formed within the first vessel under conditions effective to form a reaction product of the reactant on the interior surface of the first vessel.
The first vessel is then unseated from the vessel holder and, using the first gripper or another gripper, the first vessel is axially transported away from the vessel holder. The first vessel is then released from the gripper used to axially transport it away from the vessel holder.
Yet another aspect of the invention is a vessel having a wall at least partially enclosing a lumen. The wall has an interior polymer layer enclosed by an exterior polymer layer. One of the polymer layers is a layer at least 0.1 mm thick of a cyclic olefin copolymer (COC) resin defining a water vapor barrier. Another of the polymer layers is a layer at least 0.1 mm thick of a polyester resin.
The wall includes an oxygen barrier layer of SiOx, in which x in this formula is from about 1.5 to about 2.9, alternatively from about 1.5 to about 2.6, alternatively about 2, having a thickness of from about 10 to about 500 angstroms.
Other aspects of the invention will be apparent from the following specification and claims.
The following reference characters are used in the drawing figures:
The present invention will now be described more fully with reference to the accompanying drawings, in which several embodiments are shown. This invention can, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth here. Rather, these embodiments are examples of the invention, which has the full scope indicated by the language of the claims. Like numbers refer to like or corresponding elements throughout.
In the context of the present invention, the following definitions and abbreviations are used:
RF is radio frequency; sccm is standard cubic centimeters per minute.
The term “at least” in the context of the present invention means “equal or more” than the integer following the term. The word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality unless indicated otherwise.
“First” and “second” or similar references to, e.g., processing stations or processing devices refer to the minimum number of processing stations or devices that are present, but do not necessarily represent the order or total number of processing stations and devices. These terms do not limit the number of processing stations or the particular processing carried out at the respective stations.
For purposes of the present invention, an “organosilicon precursor” is a compound having at least one of the linkage:
which is a tetravalent silicon atom connected to an oxygen atom and an organic carbon atom (an organic carbon atom being a carbon atom bonded to at least one hydrogen atom). A volatile organosilicon precursor, defined as such a precursor that can be supplied as a vapor in a PECVD apparatus, is an optional organosilicon precursor. Optionally, the organosilicon precursor is selected from the group consisting of a linear siloxane, a monocyclic siloxane, a polycyclic siloxane, a polysilsesquioxane, an alkyl trimethoxysilane, a linear silazane, a monocyclic silazane, a polycyclic silazane, a polysilsesquiazane, and a combination of any two or more of these precursors.
In the context of the present invention, “essentially no oxygen” or (synonymously) “substantially no oxygen” is added to the gaseous reactant in some embodiments. This means that some residual atmospheric oxygen can be present in the reaction space, and residual oxygen fed in a previous step and not fully exhausted can be present in the reaction space, which are defined here as essentially no oxygen present. Essentially no oxygen is present in the gaseous reactant if the gaseous reactant comprises less than 1 vol % O2, for example less than 0.5 vol % O2, and optionally is O2-free. If no oxygen is added to the gaseous reactant, or if no oxygen at all is present during PECVD, this is also within the scope of “essentially no oxygen.”
A “vessel” in the context of the present invention can be any type of vessel with at least one opening and a wall defining an interior surface. The term “at least” in the context of the present invention means “equal or more” than the integer following the term. Thus, a vessel in the context of the present invention has one or more openings. One or two openings, like the openings of a sample tube (one opening) or a syringe barrel (two openings) are preferred. If the vessel has two openings, they can be of same or different size. If there is more than one opening, one opening can be used for the gas inlet for a PECVD coating method according to the present invention, while the other openings are either capped or open. A vessel according to the present invention can be a sample tube, e.g. for collecting or storing biological fluids like blood or urine, a syringe (or a part thereof, for example a syringe barrel) for storing or delivering a biologically active compound or composition, e.g. a medicament or pharmaceutical composition, a vial for storing biological materials or biologically active compounds or compositions, a pipe, e.g. a catheter for transporting biological materials or biologically active compounds or compositions, or a cuvette for holding fluids, e.g. for holding biological materials or biologically active compounds or compositions.
A vessel can be of any shape, a vessel having a substantially cylindrical wall adjacent to at least one of its open ends being preferred. Generally, the interior wall of the vessel is cylindrically shaped, like, e.g. in a sample tube or a syringe barrel. Sample tubes and syringes or their parts (for example syringe barrels) are contemplated.
A “lubricity layer” according to the present invention is a coating which has a lower frictional resistance than the uncoated surface. In other words, it reduces the frictional resistance of the coated surface in comparison to a reference surface which is uncoated. The present lubricity layers are primarily defined by their lower frictional resistance than the uncoated surface and the process conditions providing lower frictional resistance than the uncoated surface, and optionally can have a composition according to the empirical composition SiwOxCyHz, as defined in this Definition Section. “Frictional resistance” can be static frictional resistance and/or kinetic frictional resistance. One of the optional embodiments of the present invention is a syringe part, e.g. a syringe barrel or plunger, coated with a lubricity layer. In this contemplated embodiment, the relevant static frictional resistance in the context of the present invention is the breakout force as defined herein, and the relevant kinetic frictional resistance in the context of the present invention is the plunger sliding force as defined herein. For example, the plunger sliding force as defined and determined herein is suitable to determine the presence or absence and the lubricity characteristics of a lubricity layer in the context of the present invention whenever the coating is applied to any syringe or syringe part, for example to the inner wall of a syringe barrel. The breakout force is of particular relevance for evaluation of the coating effect on a prefilled syringe, i.e. a syringe which is filled after coating and can be stored for some time, e.g. several months or even years, before the plunger is moved again (has to be “broken out”).
The “plunger sliding force” in the context of the present invention is the force required to maintain movement of a plunger in a syringe barrel, e.g. during aspiration or dispense. It can advantageously be determined using the ISO 7886-1:1993 test described herein and known in the art. A synonym for “plunger sliding force” often used in the art is “plunger force” or “pushing force”.
The “breakout force” in the context of the present invention is the initial force required to move the plunger in a syringe, for example in a prefilled syringe.
Both “plunger sliding force” and “breakout force” and methods for their measurement are described in more detail in subsequent parts of this description.
“Slidably” means that the plunger is permitted to slide in a syringe barrel.
In the context of this invention, “substantially rigid” means that the assembled components (ports, duct, and housing, explained further below) can be moved as a unit by handling the housing, without significant displacement of any of the assembled components respecting the others. Specifically, none of the components are connected by hoses or the like that allow substantial relative movement among the parts in normal use. The provision of a substantially rigid relation of these parts allows the location of the vessel seated on the vessel holder to be nearly as well known and precise as the locations of these parts secured to the housing.
In the following, the apparatus for performing the present invention will be described first, followed by the coating methods, coatings and coated vessels, and the uses according to the present invention.
A vessel processing system is contemplated comprising a first processing station, a second processing station, a multiplicity of vessel holders, and a conveyor. The first processing station is configured for processing a vessel having an opening and a wall defining an interior surface. The second processing station is spaced from the first processing station and configured for processing a vessel having an opening and a wall defining an interior surface.
At least some, optionally all, of the vessel holders include a vessel port configured to receive and seat the opening of a vessel for processing the interior surface of a seated vessel via the vessel port at the first processing station. The conveyor is configured for transporting a series of the vessel holders and seated vessels from the first processing station to the second processing station for processing the interior surface of a seated vessel via the vessel port at the second processing station.
Referring first to
Any of the processing stations 22-36 in the illustrated embodiment can be a first processing station, any other processing station can be a second processing station, and so forth.
The embodiment illustrated in
The system 20 can include a transfer mechanism 72 for moving vessels from the injection molding machine 22 to a vessel holder 38. The transfer mechanism 72 can be configured, for example, as a robotic arm that locates, moves to, grips, transfers, orients, seats, and releases the vessels 80 to remove them from the vessel forming machine 22 and install them on the vessel holders such as 38.
The system 20 also can include a transfer mechanism at a processing station 74 for removing the vessel from one or more vessel holders such as 66, following processing the interior surface of the seated vessel such as 80 (
The processing stations or devices 32, 34, and 36 shown in
The vessel processing system 20 as illustrated in
The processing station or device 22 can be a device for forming the vessels 80. One contemplated device 22 can be an injection molding machine. Another contemplated device 22 can be a blow molding machine. Vacuum molding machines, draw molding machines, cutting or milling machines, glass drawing machines for glass or other draw-formable materials, or other types of vessel forming machines are also contemplated. Optionally, the vessel forming station 22 can be omitted, as vessels can be obtained already formed.
The portable vessel holders 38-68 are provided for holding and conveying a vessel having an opening while the vessel is processed. The vessel holder includes a vessel port, a second port, a duct, and a conveyable housing.
The vessel port is configured to seat a vessel opening in a mutually communicating relation. The second port is configured to receive an outside gas supply or vent. The duct is configured for passing one or more gases between a vessel opening seated on the vessel port and the second port. The vessel port, second port, and duct are attached in substantially rigid relation to the conveyable housing. Optionally, the portable vessel holder weighs less than five pounds. An advantage of a lightweight vessel holder is that it can more readily be transported from one processing station to another.
In certain embodiments of the vessel holder the duct more specifically is a vacuum duct and the second port more specifically is a vacuum port. The vacuum duct is configured for withdrawing a gas via the vessel port from a vessel seated on the vessel port. The vacuum port is configured for communicating between the vacuum duct and an outside source of vacuum. The vessel port, vacuum duct, and vacuum port can be attached in substantially rigid relation to the conveyable housing.
The vessel holders are shown, for example, in
The vessel holder such as 50 can be made of any material, for example thermoplastic material and/or electrically nonconductive material. Or, the vessel holder such as 50 can be made partially, or even primarily, of electrically conductive material and faced with electrically nonconductive material, for example in the passages defined by the vessel port 92, vacuum duct 94, and vacuum port 96. Examples of suitable materials for the vessel holder 50 are: a polyacetal, for example Delrin® polyacetal material sold by E.I. du Pont De Nemours and Company, Wilmington Del.; polytetrafluoroethylene (PTFE), for example Teflon® PTFE sold by E.I. du Pont De Nemours and Company, Wilmington Del.; Ultra-High-Molecular-Weight Polyethylene (UHMWPE); High density Polyethylene (HDPE); or other materials known in the art or newly discovered.
Yet another approach to treat, inspect, and/or move parts through a production system can be to use an array of vessel holders. The array can be comprised of individual pucks or be a solid array into which the devices are loaded. An array can allow more than one device, optionally many devices, to be tested, conveyed or treated/coated simultaneously. The array can be one-dimensional, for example grouped together to form a linear rack, or two-dimensional, similar to a tub or tray.
A vessel 80 can be provided having an opening 82 and a wall 86 defining an interior surface 88. As one embodiment, the vessel 80 can be formed in and then removed from a mold such as 22. Optionally within 60 seconds, or within 30 seconds, or within 25 seconds, or within 20 seconds, or within 15 seconds, or within 10 seconds, or within 5 seconds, or within 3 seconds, or within 1 second after removing the vessel from the mold, or as soon as the vessel 80 can be moved without distorting it during processing (assuming that it is made at an elevated temperature, from which it progressively cools), the vessel opening 82 can be seated on the vessel port 92. Quickly moving the vessel 80 from the mold 22 to the vessel port 92 reduces the dust or other impurities that can reach the surface 88 and occlude or prevent adhesion of the barrier or other type of coating 90. Also, the sooner a vacuum is drawn on the vessel 80 after it is made, the less chance any particulate impurities have of adhering to the interior surface 88.
The interior surface 88 of the seated vessel 80 can be then processed via the vessel port 92 at the first processing station, which can be, as one example, the barrier application or other type of coating station 28 shown in
Any of the above methods can include the further step of removing the vessel 80 from the vessel holder such as 66 following processing the interior surface 88 of the seated vessel 80 at the second processing station or device.
Any of the above methods can include the further step, after the removing step, of providing a second vessel 80 having an opening 82 and a wall 86 defining an interior surface 88. The opening 82 of the second vessel such as 80 can be seated on the vessel port 92 of another vessel holder such as 38. The interior surface of the seated second vessel 80 can be processed via the vessel port 92 at the first processing station or device such as 24. The vessel holder such as 38 and seated second vessel 80 can be transported from the first processing station or device 24 to the second processing station or device such as 26. The seated second vessel 80 can be processed via the vessel port 92 by the second processing station or device 26.
Or, the processing stations can more broadly be processing devices, and either the vessel holders can be conveyed relative to the processing devices, the processing devices can be conveyed relative to the vessel holders, or some of each arrangement can be provided in a given system. In still another arrangement, the vessel holders can be conveyed to one or more stations, and more than one processing device can be deployed at or near at least one of the stations. Thus, there is not necessarily a one-to-one correspondence between the processing devices and processing stations.
Using Gripper for Transporting Tube to and from Coating Station
Yet another embodiment is a method of PECVD treatment of a first vessel, including several steps. A first vessel is provided having an open end, a closed end, and an interior surface. At least a first gripper is configured for selectively holding and releasing the closed end of the first vessel. The closed end of the first vessel is gripped with the first gripper and, using the first gripper, transported to the vicinity of a vessel holder configured for seating to the open end of the first vessel. The first gripper is then used to axially advance the first vessel and seat its open end on the vessel holder, establishing sealed communication between the vessel holder and the interior of the first vessel.
At least one gaseous reactant is introduced within the first vessel through the vessel holder. Plasma is formed within the first vessel under conditions effective to form a reaction product of the reactant on the interior surface of the first vessel.
The first vessel is then unseated from the vessel holder and, using the first gripper or another gripper, the first vessel is axially transported away from the vessel holder. The first vessel is then released from the gripper used to axially transport it away from the vessel holder.
Referring again to
Another embodiment is a PECVD apparatus including a vessel holder, an inner electrode, an outer electrode, and a power supply. A vessel seated on the vessel holder defines a plasma reaction chamber, which optionally can be a vacuum chamber. Optionally, a source of vacuum, a reactant gas source, a gas feed or a combination of two or more of these can be supplied. Optionally, a gas drain, not necessarily including a source of vacuum, is provided to transfer gas to or from the interior of a vessel seated on the port to define a closed chamber.
The PECVD apparatus can be used for atmospheric-pressure PECVD, in which case the plasma reaction chamber does not need to function as a vacuum chamber.
In the embodiment illustrated in
Optionally in the embodiment illustrated in
The plasma screen 610, for example for embodiments in which the probe 108 also functions as an counter electrode, can make intimate electrical contact with the gas inlet 108 at or near the opening 82 of the tube, syringe barrel, or other vessel 80 being processed. Alternatively, the plasma screen 610 can be grounded, optionally having a common potential with the gas inlet 108. The plasma screen 610 reduces or eliminates the plasma in the vessel holder 50 and its internal passages and connections, for example the vacuum duct 94, the gas inlet port 104, the vicinity of the O-ring 106, the vacuum port 96, the O-ring 102, and other apparatus adjacent to the gas inlet 108. At the same time, the porosity of the plasma screen allows process gases, air, and the like to flow out of the vessel 80 into the vacuum port 96 and downstream apparatus.
Flow out of the PECVD gas source 144 is controlled by a main reactant gas valve 584 regulating flow through the main reactant feed line 586. One component of the gas source 144 is the organosilicon liquid reservoir 588. The contents of the reservoir 588 are drawn through the organosilicon capillary line 590, which is provided at a suitable length to provide the desired flow rate. Flow of organosilicon vapor is controlled by the organosilicon shut-off valve 592. Pressure is applied to the headspace 614 of the liquid reservoir 588, for example a pressure in the range of 0-15 psi (0 to 78 cm. Hg), from a pressure source 616 such as pressurized air connected to the headspace 614 by a pressure line 618 to establish repeatable organosilicon liquid delivery that is not dependent on atmospheric pressure (and the fluctuations therein). The reservoir 588 is sealed and the capillary connection 620 is at the bottom of the reservoir 588 to ensure that only neat organosilicon liquid (not the pressurized gas from the headspace 614) flows through the capillary tube 590. The organosilicon liquid optionally can be heated above ambient temperature, if necessary or desirable to cause the organosilicon liquid to evaporate, forming an organosilicon vapor. Oxygen is provided from the oxygen tank 594 via an oxygen feed line 596 controlled by a mass flow controller 598 and provided with an oxygen shut-off valve 600.
In the apparatus of
Referring especially to
In the embodiment of
In the illustrated embodiment, referring to
In
In
In
Additionally in
It should be understood that the movement of the array of inner electrodes can be independent of the movement of the vessel holders. They can be moved together or independently, to simultaneously or independently switch to a new vessel holder and/or a new inner electrode.
In the illustrated embodiment, referring to
In
In
In
Additionally in
It should be understood that the movement of the array of inner electrodes can be independent of the movement of the vessel holders. They can be moved together or independently, to simultaneously or independently switch to a new vessel holder and/or a new inner electrode.
An array of two or more inner electrodes 108, 510, and 512 is useful because the individual combined gas delivery tubes/inner electrodes 108, 510, and 512 will in some instances tend to accumulate polymerized reactant gases or some other type of deposits as they are used to coat a series of vessels such as 80. The deposits can accumulate to the point at which they detract from the coating rate or uniformity produced, which can be undesirable. To maintain a uniform process, the inner electrodes can be periodically removed from service, replaced or cleaned, and a new or cleaned electrode can be put into service. For example, going from
Thus, an inner electrode drive 530 is operable in conjunction with the inner electrode extender and retractor 514 for removing a first inner electrode 108 from its extended position to its retracted position, substituting a second inner electrode 510 for the first inner electrode 108, and advancing the second inner electrode 510 to its extended position (analogous to
The array of gas delivery tubes of
The electrode 160 shown in
The electrode in
PECVD Apparatus Using Gripper for Transporting Tube to and from Coating Station
Another embodiment is an apparatus for PECVD treatment of a vessel, employing a gripper as previously described.
The first gripper 204, and as illustrated any of the grippers 204, is configured for selectively holding and releasing the closed end 84 of a vessel 80. While gripping the closed end 84 of the vessel, the first gripper 204 can transport the vessel to the vicinity of the vessel holder 48. In the illustrated embodiment, the transportation function is facilitated by a series conveyor 538 to which the grippers 204 are attached in a series.
The vessel holder 48 has previously been described in connection with other embodiments, and is configured for seating to the open end 82 of a vessel 80. The seat defined by the vessel port 92 has previously been described in connection with other embodiments, and is configured for establishing sealed communication between the vessel holder 48 and the interior space 88 of the first vessel, and in this case any of the vessels 80. The reactant supply 144 has previously been described in connection with other embodiments, and is operatively connected for introducing at least one gaseous reactant within the first vessel 80 through the vessel holder 48. The plasma generator defined by the electrodes 108 and 160 has previously been described in connection with other embodiments, and is configured for forming plasma within the first vessel under conditions effective to form a reaction product of the reactant on the interior surface of the first vessel.
The vessel release 534 or other expedients, such as introducing within the seated vessel 80 a reactant gas, a carrier gas, or an inexpensive gas such as compressed nitrogen or air, can be used for unseating the first vessel 80 from the vessel holder 48.
The grippers 204 are configured for axially transporting the first vessel 80 away from the vessel holder 48 and then releasing the first vessel 80, as by releasing suction from between the gripper 48 and the vessel end 84.
Continuing, plasma is formed within the first vessel under conditions effective to form a reaction product of the reactant on the interior surface of the first vessel, optionally as explained for previous embodiments. The first vessel is unseated from the vessel holder, optionally as explained for previous embodiments. The first gripper or another gripper is used, optionally as explained for previous embodiments, to axially transport the first vessel away from the vessel holder. The first vessel can then be released from the gripper used to axially transport it away from the vessel holder, optionally as explained for previous embodiments.
Further optional steps that can be carried out according to this method include providing a reaction vessel different from the first vessel, the reaction vessel having an open end and an interior space, and seating the open end of the reaction vessel on the vessel holder, establishing sealed communication between the vessel holder and the interior space of the reaction vessel. A PECVD reactant conduit can be provided within the interior space. Plasma can be formed within the interior space of the reaction vessel under conditions effective to remove at least a portion of a deposit of a PECVD reaction product from the reactant conduit. These reaction conditions have been explained in connection with a previously described embodiment. The reaction vessel then can be unseated from the vessel holder and transported away from the vessel holder.
Further optional steps that can be carried out according to any embodiment of this method include:
Thus,
As
The mechanism of
The plasma generator defined by the electrodes 108 and 160 is configurable for forming plasma within the interior space of the reaction vessel 532 under conditions effective to remove at least a portion of a deposit of a PECVD reaction product from the reactant conduit 108. It is contemplated above that the inner electrode and gas source 108 can be a conductive tube, for example a metallic tube, and that the reaction vessel 532 can be made of any suitable, optionally heat-resistant material such as ceramic, quartz, glass or other materials that can withstand more heat than a thermoplastic vessel. The material of the reaction vessel 532 also can desirably be chemical or plasma resistant to the conditions used in the reaction vessel to remove deposits of reaction products. Optionally, the reaction vessel 532 can be made of electrically conductive material and itself serve as a special-purpose outer electrode for the purpose of removing deposits from the reactant conduit 108. As yet another alternative, the reaction vessel 532 can be configured as a cap that seats on the outer electrode 160, in which case the outer electrode 160 would optionally be seated on the vessel holder 48 to define a closed cleaning reaction chamber.
It is contemplated that the reaction conditions effective to remove at least a portion of a deposit of a PECVD reaction product from the reactant conduit 108 include introduction of a substantial portion of an oxidizing reactant such as oxygen or ozone (either generated separately or by the plasma apparatus), a higher power level than is used for deposition of coatings, a longer cycle time than is used for deposition of coatings, or other expedients known for removing the type of unwanted deposit encountered on the reaction conduit 108. For another example, mechanical milling can also be used to remove unwanted deposits. Or, solvents or other agents can be forced through the reactant conduit 108 to clear obstructions. These conditions can be far more severe than what the vessels 80 to be coated can withstand, since the reaction vessel 532 does not need to be suitable for the normal uses of the vessel 80. Optionally, however, a vessel 80 can be used as the reaction vessel, and if the deposit removing conditions are too severe the vessel 80 employed as a reaction vessel can be discarded, in an alternative embodiment.
The precursor for the PECVD coating of the present invention is broadly defined as an organometallic precursor. An organometallic precursor is defined in this specification as comprehending compounds of metal elements from Group III and/or Group IV of the Periodic Table having organic residues, e.g. hydrocarbon, aminocarbon or oxycarbon residues. Organometallic compounds as presently defined include any precursor having organic moieties bonded to silicon or other Group III/IV metal atoms directly, or optionally bonded through oxygen or nitrogen atoms. The relevant elements of Group III of the Periodic Table are Boron, Aluminum, Gallium, Indium, Thallium, Scandium, Yttrium, and Lanthanum, Aluminum and Boron being preferred. The relevant elements of Group IV of the Periodic Table are Silicon, Germanium, Tin, Lead, Titanium, Zirconium, Hafnium, and Thorium, with Silicon and Tin being preferred. Other volatile organic compounds can also be contemplated. However, organosilicon compounds are preferred for performing present invention.
An organosilicon precursor is contemplated, where an “organosilicon precursor” is defined throughout this specification most broadly as a compound having at least one of the linkages:
The first structure immediately above is a tetravalent silicon atom connected to an oxygen atom and an organic carbon atom (an organic carbon atom being a carbon atom bonded to at least one hydrogen atom). The second structure immediately above is a tetravalent silicon atom connected to an —NH— linkage and an organic carbon atom (an organic carbon atom being a carbon atom bonded to at least one hydrogen atom). Optionally, the organosilicon precursor is selected from the group consisting of a linear siloxane, a monocyclic siloxane, a polycyclic siloxane, a polysilsesquioxane, a linear silazane, a monocyclic silazane, a polycyclic silazane, a polysilsesquiazane, and a combination of any two or more of these precursors. Also contemplated as a precursor, though not within the two formulas immediately above, is an alkyl trimethoxysilane.
If an oxygen-containing precursor (e.g. a siloxane) is used, a representative predicted empirical composition resulting from PECVD under conditions forming a lubricating coating would be SiwOxCyHz as defined in the Definition Section, while a representative predicted empirical composition resulting from PECVD under conditions forming a barrier layer would be SiOx, where x in this formula is from about 1.5 to about 2.9. If a nitrogen-containing precursor (e.g. a silazane) is used, the predicted composition would be Siw*Nx*Cy*Hz*, i.e. in SiwOxCyHz as specified in the Definition Section, O is replaced by N and the indices are adapted to the higher valency of N as compared to O (3 instead of 2). The latter adaptation will generally follow the ratio of w, x, y and z in a siloxane to the corresponding indices in its aza counterpart. In a particular aspect of the invention, Siw*Nx*Cy*Hz* in which w*, x*, y*, and z* are defined the same as w, x, y, and z for the siloxane counterparts, but for an optional deviation in the number of hydrogen atoms.
One type of precursor starting material having the above empirical formula is a linear siloxane, for example a material having the following formula:
in which each R is independently selected from alkyl, for example methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, vinyl, alkyne, or others, and n is 1, 2, 3, 4, or greater, optionally two or greater. Several examples of contemplated linear siloxanes are hexamethyldisiloxane (HMDSO), octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, or combinations of two or more of these. The analogous silazanes in which —NH— is substituted for the oxygen atom in the above structure are also useful for making analogous coatings. Several examples of contemplated linear silazanes are octamethyltrisilazane, decamethyltetrasilazane, or combinations of two or more of these.
Another type of precursor starting material is a monocyclic siloxane, for example a material having the following structural formula:
in which R is defined as for the linear structure and “a” is from 3 to about 10, or the analogous monocyclic silazanes. Several examples of contemplated hetero-substituted and unsubstituted monocyclic siloxanes and silazanes include
Another type of precursor starting material is a polycyclic siloxane, for example a material having one of the following structural formulas:
in which Y can be oxygen or nitrogen, E is silicon, and Z is a hydrogen atom or an organic substituent, for example alkyl such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, vinyl, alkyne, or others. When each Y is oxygen, the respective structures, from left to right, are a silatrane, a silquasilatrane, and a silproatrane. When Y is nitrogen, the respective structures are an azasilatrane, an azasilquasiatrane, and an azasilproatrane.
Another type of polycyclic siloxane precursor starting material is a polysilsesquioxane, with the empirical formula RSiO1.5 and the structural formula shown as a T8 cube:
in which each R is a hydrogen atom or an organic substituent, for example alkyl such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, vinyl, alkyne, or others. Two commercial materials of this sort are a T8 cube, available as a commercial product SST-eM01 poly(methylsilsesquioxane), in which each R is methyl, and another T8 cube, available as a commercial product SST-3 MH1.1 poly(Methyl-Hydridosilsesquioxane), in which 90% of the R groups are methyl, 10% are hydrogen atoms. This material is available in a 10% solution in tetrahydrofuran, for example. Combinations of two or more of these are also contemplated. Other examples of a contemplated precursor are methylsilatrane, CAS No. 2288-13-3, in which each Y is oxygen and Z is methyl, methylazasilatrane, or a combination of any two or more of these.
The analogous polysilsesquiazanes in which —NH— is substituted for the oxygen atom in the above structure are also useful for making analogous coatings. Examples of contemplated polysilsesquiazanes are a poly(methylsilsesquiazane), in which each R is methyl, and a poly(Methyl-Hydridosilsesquiazane, in which 90% of the R groups are methyl, 10% are hydrogen atoms. Combinations of two or more of these are also contemplated.
One particularly contemplated precursor for the lubricity layer according to the present invention is a monocyclic siloxane, for example is octamethylcyclotetrasiloxane.
One particularly contemplated precursor for the barrier layer according to the present invention is a linear siloxane, for example is HMDSO.
In any of the coating methods according to the present invention, the applying step optionally can be carried out by vaporizing the precursor and providing it in the vicinity of the substrate. E.g., OMCTS is usually vaporized by heating it to about 50.degree. C. before applying it to the PECVD apparatus.
In the context of the present invention, the following PECVD method is generally applied, which contains the following steps:
(a) providing a gaseous reactant comprising a precursor as defined herein, optionally an organosilicon precursor, and optionally O2 in the vicinity of the substrate surface; and
(b) generating plasma from the gaseous reactant, thus forming a coating on the substrate surface by plasma enhanced chemical vapor deposition (PECVD).
In the method, the coating characteristics are advantageously set by one or more of the following conditions: the plasma properties, the pressure under which the plasma is applied, the power applied to generate the plasma, the presence and relative amount of O2 in the gaseous reactant, the plasma volume, and the organosilicon precursor. Optionally, the coating characteristics are set by the presence and relative amount of O2 in the gaseous reactant and/or the power applied to generate the plasma.
In all embodiments of the present invention, the plasma is in an optional aspect a non-hollow-cathode plasma.
In a further preferred aspect, the plasma is generated at reduced pressure (as compared to the ambient or atmospheric pressure). Optionally, the reduced pressure is less than 300 mTorr, optionally less than 200 mTorr, even optionally less than 100 mTorr.
The PECVD optionally is performed by energizing the gaseous reactant containing the precursor with electrodes powered at a frequency at microwave or radio frequency, and optionally at a radio frequency. The radio frequency preferred to perform an embodiment of the invention will also be addressed as “RF frequency”. A typical radio frequency range for performing the present invention is a frequency of from 10 kHz to less than 300 MHz, optionally from 1 to 50 MHz, even optionally from 10 to 15 MHz. A frequency of 13.56 MHz is most preferred, this being a government sanctioned frequency for conducting PECVD work.
There are several advantages for using a RF power source versus a microwave source: Since RF operates a lower power, there is less heating of the substrate/vessel. Because the focus of the present invention is putting a plasma coating on plastic substrates, lower processing temperature are desired to prevent melting/distortion of the substrate. To prevent substrate overheating when using microwave PECVD, the microwave PECVD is applied in short bursts, by pulsing the power. The power pulsing extends the cycle time for the coating, which is undesired in the present invention. The higher frequency microwave can also cause offgassing of volatile substances like residual water, oligomers and other materials in the plastic substrate. This offgassing can interfere with the PECVD coating. A major concern with using microwave for PECVD is delamination of the coating from the substrate. Delamination occurs because the microwaves change the surface of the substrate prior to depositing the coating layer. To mitigate the possibility of delamination, interface coating layers have been developed for microwave PECVD to achieve good bonding between the coating and the substrate. Finally, the lubricity layers according to the present invention are advantageously applied using lower power. RF power operates at lower power and provides more control over the PECVD process than microwave power. Nonetheless, microwave power, though less preferred, is usable under suitable process conditions.
Furthermore, for all PECVD methods described herein, there is a specific correlation between the power (in Watts) used to generate the plasma and the volume of the lumen wherein the plasma is generated. Typically, the lumen is the lumen of a vessel coated according to the present invention. The RF power should scale with the volume of the vessel if the same electrode system is employed. Once the composition of a gaseous reactant, for example the ratio of the precursor to O2, and all other parameters of the PECVD coating method but the power have been set, they will typically not change when the geometry of a vessel is maintained and only its volume is varied. In this case, the power will be directly proportional to the volume. Thus, starting from the power to volume ratios provided by present description, the power which has to be applied in order to achieve the same or a similar coating in a vessel of same geometry, but different size, can easily be found. The influence of the vessel geometry on the power to be applied is illustrated by the results of the Examples for tubes in comparison to the Examples for syringe barrels.
For any coating of the present invention, the plasma is generated with electrodes powered with sufficient power to form a coating on the substrate surface. For a lubricity layer, in the method according to an embodiment of the invention the plasma is optionally generated (i) with electrodes supplied with an electric power of from 0.1 to 25 W, optionally from 1 to 22 W, optionally from 3 to 17 W, even optionally from 5 to 14 W, optionally from 7 to 11 W, for example of 8 W; and/or (ii) wherein the ratio of the electrode power to the plasma volume is less than 10 W/ml, optionally is from 5 W/ml to 0.1 W/ml, optionally is from 4 W/ml to 0.1 W/ml, optionally from 2 W/ml to 0.2 W/ml. For a barrier layer or SiOx coating, the plasma is optionally generated (i) with electrodes supplied with an electric power of from 8 to 500 W, optionally from 20 to 400 W, optionally from 35 to 350 W, even optionally from 44 to 300 W, optionally from 44 to 70 W; and/or (ii) the ratio of the electrode power to the plasma volume is equal or more than 5 W/ml, optionally is from 6 W/ml to 150 W/ml, optionally is from 7 W/ml to 100 W/ml, optionally from 7 W/ml to 20 W/ml.
The vessel geometry can also influence the choice of the gas inlet used for the PECVD coating. In a particular aspect, a syringe can be coated with an open tube inlet, and a tube can be coated with a gas inlet having small holes which is extended into the tube.
The power (in Watts) used for PECVD also has an influence on the coating properties. Typically, an increase of the power will increase the barrier properties of the coating, and a decrease of the power will increase the lubricity of the coating. E.g., for a coating on the inner wall of syringe barrel having a volume of about 3 ml, a power of less than 30 W will lead to a coating which is predominantly a barrier layer, while a power of more than 30 W will lead to a coating which is predominantly a lubricity layer (see Examples).
A further parameter determining the coating properties is the ratio of O2 (or another oxidizing agent) to the precursor (e.g. organosilicon precursor) in the gaseous reactant used for generating the plasma. Typically, an increase of the O2 ratio in the gaseous reactant will increase the barrier properties of the coating, and a decrease of the O2 ratio will increase the lubricity of the coating.
If a lubricity layer is desired, then O2 is optionally present in a volume-volume ratio to the gaseous reactant of from 0:1 to 5:1, optionally from 0:1 to 1:1, even optionally from 0:1 to 0.5:1 or even from 0:1 to 0.1:1. Most advantageously, essentially no oxygen is present in the gaseous reactant. Thus, the gaseous reactant will in some embodiments comprise less than 1 vol % O2, for example less than 0.5 vol % O2, and optionally is O2-free.
If, on the other hand, a barrier or SiOx coating is desired, then the O2 is optionally present in a volume:volume ratio to the gaseous reactant of from 1:1 to 100:1 in relation to the silicon containing precursor, optionally in a ratio of from 5:1 to 30:1, optionally in a ratio of from 10:1 to 20:1, even optionally in a ratio of 15:1.
PECVD to Apply SiOx Barrier Layer, Using Plasma that is Substantially Free of Hollow Cathode Plasma
A specific embodiment is a method of applying a barrier layer of SiOx, defined in this specification (unless otherwise specified in a particular instance) as a coating containing silicon, oxygen, and optionally other elements, in which x, the ratio of oxygen to silicon atoms, is from about 1.5 to about 2.9, or 1.5 to about 2.6, or about 2. These alternative definitions of x apply to any use of the term SiOx in this specification. The barrier layer is applied to the interior of a vessel, for example a sample collection tube, a syringe barrel, or another type of vessel. The method includes several steps.
A vessel wall is provided, as is a reaction mixture comprising plasma forming gas, i.e. an organosilicon compound gas, optionally an oxidizing gas, and optionally a hydrocarbon gas.
Plasma is formed in the reaction mixture that is substantially free of hollow cathode plasma. The vessel wall is contacted with the reaction mixture, and the coating of SiOx is deposited on at least a portion of the vessel wall.
In certain embodiments, the generation of a uniform plasma throughout the portion of the vessel to be coated is contemplated, as it has been found in certain instances to generate an SiOx coating providing a better barrier against oxygen. Uniform plasma means regular plasma that does not include a substantial amount of hollow cathode plasma (which has a higher emission intensity than regular plasma and is manifested as a localized area of higher intensity interrupting the more uniform intensity of the regular plasma).
The hollow cathode effect is generated by a pair of conductive surfaces opposing each other with the same negative potential with respect to a common anode. If the spacing is made (depending on the pressure and gas type) such that the space charge sheaths overlap, electrons start to oscillate between the reflecting potentials of the opposite wall sheaths leading to multiple collisions as the electrons are accelerated by the potential gradient across the sheath region. The electrons are confined in the space charge sheath overlap which results in very high ionization and high ion density plasmas. This phenomenon is described as the hollow cathode effect. Those skilled in the art are able to vary the processing conditions, such as the power level and the feed rates or pressure of the gases, to form uniform plasma throughout or to form plasma including various degrees of hollow cathode plasma.
The inventors have found that the uniformity of coating can be improved in certain embodiments by repositioning the distal end of the electrode 308 relative to the vessel 250 so it does not penetrate as far into the lumen 300 of the vessel 250 as the position of the inner electrode shown in previous Figures. For example, although in certain embodiments the distal opening 316 can be positioned adjacent to the restricted opening 294, in other embodiments the distal opening 316 can be positioned less than 7/8 the distance, optionally less than 3/4 the distance, optionally less than half the distance to the restricted opening 294 from the larger opening 302 of the vessel to be processed while feeding the reactant gas. Or, the distal opening 316 can be positioned less than 40%, less than 30%, less than 20%, less than 15%, less than 10%, less than 8%, less than 6%, less than 4%, less than 2%, or less than 1% of the distance to the restricted opening 294 from the larger opening of the vessel to be processed while feeding the reactant gas.
Or, the distal end of the electrode 308 can be positioned either slightly inside or outside or flush with the larger opening 302 of the vessel 250 to be processed while communicating with, and feeding the reactant gas to, the interior of the vessel 250. The positioning of the distal opening 316 relative to the vessel 250 to be processed can be optimized for particular dimensions and other conditions of treatment by testing it at various positions. One particular position of the electrode 308 contemplated for treating syringe barrels 250 is with the distal end 314 penetrating about a quarter inch (about 6 mm) into the vessel lumen 300 above the larger opening 302.
The inventors presently contemplate that it is advantageous to place at least the distal end 314 of the electrode 308 within the vessel 250 so it will function suitably as an electrode, though that is not necessarily a requirement. Surprisingly, the plasma 318 generated in the vessel 250 can be made more uniform, extending through the restricted opening 294 into the processing vessel lumen 304, with less penetration of the electrode 308 into the lumen 300 than has previously been employed. With other arrangements, such as processing a closed-ended vessel, the distal end 314 of the electrode 308 commonly is placed closer to the closed end of the vessel than to its entrance.
Or, the distal end 314 of the electrode 308 can be positioned at the restricted opening 294 or beyond the restricted opening 294, for example within the processing vessel lumen 304. Various expedients can optionally be provided, such as shaping the processing vessel 296 to improve the gas flow through the restricted opening 294.
In yet another contemplated embodiment, the inner electrode 160 as in
Another embodiment is a method of applying a lubricity layer derived from an organosilicon precursor. A “lubricity layer” or any similar term is generally defined as a coating that reduces the frictional resistance of the coated surface, relative to the uncoated surface. If the coated object is a syringe (or syringe part, e.g. syringe barrel) or any other item generally containing a plunger or movable part in sliding contact with the coated surface, the frictional resistance has two main aspects—breakout force and plunger sliding force.
The plunger sliding force test is a specialized test of the coefficient of sliding friction of the plunger within a syringe, accounting for the fact that the normal force associated with a coefficient of sliding friction as usually measured on a flat surface is addressed by standardizing the fit between the plunger or other sliding element and the tube or other vessel within which it slides. The parallel force associated with a coefficient of sliding friction as usually measured is comparable to the plunger sliding force measured as described in this specification. Plunger sliding force can be measured, for example, as provided in the ISO 7886-1:1993 test.
The plunger sliding force test can also be adapted to measure other types of frictional resistance, for example the friction retaining a stopper within a tube, by suitable variations on the apparatus and procedure. In one embodiment, the plunger can be replaced by a closure and the withdrawing force to remove or insert the closure can be measured as the counterpart of plunger sliding force.
Also or instead of the plunger sliding force, the breakout force can be measured. The breakout force is the force required to start a stationary plunger moving within a syringe barrel, or the comparable force required to unseat a seated, stationary closure and begin its movement. The breakout force is measured by applying a force to the plunger that starts at zero or a low value and increases until the plunger begins moving. The breakout force tends to increase with storage of a syringe, after the prefilled syringe plunger has pushed away the intervening lubricant or adhered to the barrel due to decomposition of the lubricant between the plunger and the barrel. The breakout force is the force needed to overcome “sticktion,” an industry term for the adhesion between the plunger and barrel that needs to be overcome to break out the plunger and allow it to begin moving.
Some utilities of coating a vessel in whole or in part with a lubricity layer, such as selectively at surfaces contacted in sliding relation to other parts, is to ease the insertion or removal of a stopper or passage of a sliding element such as a piston in a syringe or a stopper in a sample tube. The vessel can be made of glass or a polymer material such as polyester, for example polyethylene terephthalate (PET), a cyclic olefin copolymer (COC), an olefin such as polypropylene, or other materials. Applying a lubricity layer by PECVD can avoid or reduce the need to coat the vessel wall or closure with a sprayed, dipped, or otherwise applied organosilicon or other lubricant that commonly is applied in a far larger quantity than would be deposited by a PECVD process.
In any of the present embodiments, a plasma, optionally a non-hollow-cathode plasma, optionally can be formed in the vicinity of the substrate
In any of the present embodiments, the precursor optionally can be provided in the substantial absence of oxygen. In any of the present embodiments, the precursor optionally can be provided in the substantial absence of a carrier gas. In any of the present embodiments, the precursor optionally can be provided in the substantial absence of nitrogen. In any of the present embodiments, the precursor optionally can be provided at less than 1 Torr absolute pressure.
In any of the present embodiments, the precursor optionally can be provided to the vicinity of a plasma emission.
In any of the present embodiments, the coating optionally can be applied to the substrate at a thickness of 1 to 5000 nm, or 10 to 1000 nm, or 10-200 nm, or 20 to 100 nm thick. The thickness of this and other coatings can be measured, for example, by transmission electron microscopy (TEM).
The TEM can be carried out, for example, as follows. Samples can be prepared for Focused Ion Beam (FIB) cross-sectioning in two ways. Either the samples can be first coated with a thin layer of carbon (50-100 nm thick) and then coated with a sputtered layer of platinum (50-100 nm thick) using a K575X Emitech coating system, or the samples can be coated directly with the protective sputtered Pt layer. The coated samples can be placed in an FEI FIB200 FIB system. An additional layer of platinum can be FIB-deposited by injection of an oregano-metallic gas while rastering the 30 kV gallium ion beam over the area of interest. The area of interest for each sample can be chosen to be a location half way down the length of the syringe barrel. Thin cross sections measuring approximately 15.mu.m (“micrometers”) long, 2.mu.m wide and 15.mu.m deep can be extracted from the die surface using a proprietary in-situ FIB lift-out technique. The cross sections can be attached to a 200 mesh copper TEM grid using FIB-deposited platinum. One or two windows in each section, measuring .about.8.mu.m wide, can be thinned to electron transparency using the gallium ion beam of the FEI FIB.
Cross-sectional image analysis of the prepared samples can be performed utilizing either a Transmission Electron Microscope (TEM), or a Scanning Transmission Electron Microscope (STEM), or both. All imaging data can be recorded digitally. For STEM imaging, the grid with the thinned foils can be transferred to a Hitachi HD2300 dedicated STEM. Scanning transmitted electron images can be acquired at appropriate magnifications in atomic number contrast mode (ZC) and transmitted electron mode (TE). The following instrument settings can be used.
For TEM analysis the sample grids can be transferred to a Hitachi HF2000 transmission electron microscope. Transmitted electron images can be acquired at appropriate magnifications. The relevant instrument settings used during image acquisition can be those given below.
In any of the present embodiments, the substrate can comprise glass or a polymer, for example a polycarbonate polymer, an olefin polymer, a cyclic olefin copolymer, a polypropylene polymer, a polyester polymer, a polyethylene terephthalate polymer or a combination of any two or more of these.
In any of the present embodiments, the PECVD optionally can be performed by energizing the gaseous reactant containing the precursor with electrodes powered at a RF frequency as defined above, for example a frequency from 10 kHz to less than 300 MHz, optionally from 1 to 50 MHz, even optionally from 10 to 15 MHz, optionally a frequency of 13.56 MHz.
In any of the present embodiments, the plasma can be generated by energizing the gaseous reactant comprising the precursor with electrodes supplied with electric power sufficient to form a lubricity layer. Optionally, the plasma is generated by energizing the gaseous reactant containing the precursor with electrodes supplied with an electric power of from 0.1 to 25 W, optionally from 1 to 22 W, optionally from 3 to 17 W, even optionally from 5 to 14 W, optionally from 7 to 11 W, optionally 8 W. The ratio of the electrode power to the plasma volume can be less than 10 W/ml, optionally is from 5 W/ml to 0.1 W/ml, optionally is from 4 W/ml to 0.1 W/ml, optionally from 2 W/ml to 0.2 W/ml. These power levels are suitable for applying lubricity coatings to syringes and sample tubes and vessels of similar geometry having a void volume of 1 to 3 mL in which PECVD plasma is generated. It is contemplated that for larger or smaller objects the power applied should be increased or reduced accordingly to scale the process to the size of the substrate.
One contemplated product optionally can be a syringe having a barrel treated by the method of any one or more of embodiments
Another example of a suitable barrier or other type of coating, usable in conjunction with PECVD-applied coatings or other PECVD treatment as disclosed here, can be a liquid barrier, lubricant, or other type of coating 90 applied to the interior surface of a vessel, either directly or with one or more intervening PECVD-applied coatings described in this specification, for example SiOx, a lubricity layer characterized as defined in the Definition Section, or both.
Suitable liquid barriers or other types of coatings 90 also optionally can be applied, for example, by applying a liquid monomer or other polymerizable or curable material to the interior surface of the vessel 80 and curing, polymerizing, or crosslinking the liquid monomer to form a solid polymer. Suitable liquid barrier or other types of coatings 90 can also be provided by applying a solvent-dispersed polymer to the surface 88 and removing the solvent.
Either of the above methods can include as a step forming a coating 90 on the interior 88 of a vessel 80 via the vessel port 92 at a processing station or device 28. One example is applying a liquid coating, for example of a curable monomer, prepolymer, or polymer dispersion, to the interior surface 88 of a vessel 80 and curing it to form a film that physically isolates the contents of the vessel 80 from its interior surface 88. The prior art describes polymer coating technology as suitable for coating plastic blood collection tubes. For example, the acrylic and polyvinylidene chloride (PVdC) coating materials and coating methods described in U.S. Pat. No. 6,165,566, which is hereby incorporated by reference, optionally can be used.
Either of the above methods can also or include as a step forming a coating on the exterior outer wall of a vessel 80. The coating optionally can be a barrier layer, optionally an oxygen barrier layer, or optionally a water barrier layer. One example of a suitable coating is polyvinylidene chloride, which functions both as a water barrier and an oxygen barrier. Optionally, the barrier layer can be applied as a water-based coating. The coating optionally can be applied by dipping the vessel in it, spraying it on the vessel, or other expedients. A vessel having an exterior barrier layer as described above is also contemplated.
Vessels are contemplated having a barrier layer 90 (shown in
It is contemplated that the choice of the material to be barred from permeating the coating and the nature of the SiOx coating applied can affect its barrier efficacy. For example, two examples of material commonly intended to be barred are oxygen and water/water vapor. Materials commonly are a better barrier to one than to the other. This is believed to be so at least in part because oxygen is transmitted through the coating by a different mechanism than water is transmitted.
Oxygen transmission is affected by the physical features of the coating, such as its thickness, the presence of cracks, and other physical details of the coating. Water transmission, on the other hand, is believed to commonly be affected by chemical factors, i.e. the material of which the coating is made, more than physical factors. The inventors also believe that at least one of these chemical factors is a substantial concentration of OH moieties in the coating, which leads to a higher transmission rate of water through the barrier. An SiOx coating often contains OH moieties, and thus a physically sound coating containing a high proportion of OH moieties is a better barrier to oxygen than to water. A physically sound carbon-based barrier, such as amorphous carbon or diamond-like carbon (DLC) commonly is a better barrier to water than is an SiOx coating because the carbon-based barrier more commonly has a lower concentration of OH moieties.
Other factors lead to a preference for an SiOx coating, however, such as its oxygen barrier efficacy and its close chemical resemblance to glass and quartz. Glass and quartz (when used as the base material of a vessel) are two materials long known to present a very high barrier to oxygen and water transmission as well as substantial inertness to many materials commonly carried in vessels. Thus, it is commonly desirable to optimize the water barrier properties such as the water vapor transmission rate (WVTR) of an SiOx coating, rather than choosing a different or additional type of coating to serve as a water transmission barrier.
Several ways contemplated to improve the WVTR of an SiOx coating are as follow.
The concentration ratio of organic moieties (carbon and hydrogen compounds) to OH moieties in the deposited coating can be increased. This can be done, for example, by increasing the proportion of oxygen in the feed gases (as by increasing the oxygen feed rate or by lowering the feed rate of one or more other constituents). The lowered incidence of OH moieties is believed to result from increasing the degree of reaction of the oxygen feed with the hydrogen in the silicone source to yield more volatile water in the PECVD exhaust and a lower concentration of OH moieties trapped or incorporated in the coating.
Higher energy can be applied in the PECVD process, either by raising the plasma generation power level, by applying the power for a longer period, or both. An increase in the applied energy must be employed with care when used to coat a plastic tube or other device, as it also has a tendency to distort the vessel being treated, to the extent the tube absorbs the plasma generation power. This is why RF power is contemplated in the context of present application. Distortion of the medical devices can be reduced or eliminated by employing the energy in a series of two or more pulses separated by cooling time, by cooling the vessels while applying energy, by applying the coating in a shorter time (commonly thus making it thinner), by selecting a frequency of the applied coating that is absorbed minimally by the base material selected for being coated, and/or by applying more than one coating, with time in between the respective energy application steps. For example, high power pulsing can be used with a duty cycle of 1 millisecond on, 99 milliseconds off, while continuing to feed the process gas. The process gas is then the coolant, as it keeps flowing between pulses. Another alternative is to reconfigure the power applicator, as by adding magnets to confine the plasma increase the effective power application (the power that actually results in incremental coating, as opposed to waste power that results in heating or unwanted coating). This expedient results in the application of more coating-formation energy per total Watt-hour of energy applied. See for example U.S. Pat. No. 5,904,952.
An oxygen post-treatment of the coating can be applied to remove OH moieties from the previously-deposited coating. This treatment is also contemplated to remove residual volatile organosilicon compounds or silicones or oxidize the coating to form additional SiOx.
The plastic base material tube can be preheated.
A different volatile source of silicon, such as hexamethyldisilazane (HMDZ), can be used as part or all of the silicone feed. It is contemplated that changing the feed gas to HMDZ will address the problem because this compound has no oxygen moieties in it, as supplied. It is contemplated that one source of OH moieties in the HMDSO-sourced coating is hydrogenation of at least some of the oxygen atoms present in unreacted HMDSO.
A composite coating can be used, such as a carbon-based coating combined with SiOx. This can be done, for example, by changing the reaction conditions or by adding a substituted or unsubstituted hydrocarbon, such as an alkane, alkene, or alkyne, to the feed gas as well as an organosilicon-based compound. See for example U.S. Pat. No. 5,904,952, which states in relevant part: “For example, inclusion of a lower hydrocarbon such as propylene provides carbon moieties and improves most properties of the deposited films (except for light transmission), and bonding analysis indicates the film to be silicon dioxide in nature. Use of methane, methanol, or acetylene, however, produces films that are silicone in nature. The inclusion of a minor amount of gaseous nitrogen to the gas stream provides nitrogen moieties in the deposited films and increases the deposition rate, improves the transmission and reflection optical properties on glass, and varies the index of refraction in response to varied amounts of N2. The addition of nitrous oxide to the gas stream increases the deposition rate and improves the optical properties, but tends to decrease the film hardness.”
A diamond-like carbon (DLC) coating can be formed as the primary or sole coating deposited. This can be done, for example, by changing the reaction conditions or by feeding methane, hydrogen, and helium to a PECVD process. These reaction feeds have no oxygen, so no OH moieties can be formed. For one example, an SiOx coating can be applied on the interior of a tube or syringe barrel and an outer DLC coating can be applied on the exterior surface of a tube or syringe barrel. Or, the SiOx and DLC coatings can both be applied as a single layer or plural layers of an interior tube or syringe barrel coating.
Referring to
Any coating described herein can be used for coating a surface, for example a plastic surface. It can further be used as a barrier layer, for example as a barrier against a gas or liquid, optionally against water vapor, oxygen and/or air. It can also be used for preventing or reducing mechanical and/or chemical effects which the coated surface would have on a compound or composition if the surface were uncoated. For example, it can prevent or reduce the precipitation of a compound or composition, for example insulin precipitation or blood clotting or platelet activation.
Referring to
The vessel 80 can be made, for example, of thermoplastic material. Some examples of suitable thermoplastic material are polyethylene terephthalate or a polyolefin such as polypropylene or a cyclic polyolefin copolymer.
The vessel 80 can be made by any suitable method, such as by injection molding, by blow molding, by machining, by fabrication from tubing stock, or by other suitable means. PECVD can be used to form a coating on the internal surface of SiOx.
If intended for use as an evacuated blood collection tube, the vessel 80 desirably can be strong enough to withstand a substantially total internal vacuum substantially without deformation when exposed to an external pressure of 760 Torr or atmospheric pressure and other coating processing conditions. This property can be provided, in a thermoplastic vessel 80, by providing a vessel 80 made of suitable materials having suitable dimensions and a glass transition temperature higher than the processing temperature of the coating process, for example a cylindrical wall 86 having sufficient wall thickness for its diameter and material.
Medical vessels or containers like sample collection tubes and syringes are relatively small and are injection molded with relatively thick walls, which renders them able to be evacuated without being crushed by the ambient atmospheric pressure. They are thus stronger than carbonated soft drink bottles or other larger or thinner-walled plastic containers. Since sample collection tubes designed for use as evacuated vessels typically are constructed to withstand a full vacuum during storage, they can be used as vacuum chambers.
Such adaptation of the vessels to be their own vacuum chambers might eliminate the need to place the vessels into a vacuum chamber for PECVD treatment, which typically is carried out at very low pressure. The use of a vessel as its own vacuum chamber can result in faster processing time (since loading and unloading of the parts from a separate vacuum chamber is not necessary) and can lead to simplified equipment configurations. Furthermore, a vessel holder is contemplated, for certain embodiments, that will hold the device (for alignment to gas tubes and other apparatus), seal the device (so that the vacuum can be created by attaching the vessel holder to a vacuum pump) and move the device between molding and subsequent processing steps.
A vessel 80 used as an evacuated blood collection tube should be able to withstand external atmospheric pressure, while internally evacuated to a reduced pressure useful for the intended application, without a substantial volume of air or other atmospheric gas leaking into the tube (as by bypassing the closure) or permeating through the wall 86 during its shelf life. If the as-molded vessel 80 cannot meet this requirement, it can be processed by coating the interior surface 88 with a barrier or other type of coating 90. It is desirable to treat and/or coat the interior surfaces of these devices (such as sample collection tubes and syringe barrels) to impart various properties that will offer advantages over existing polymeric devices and/or to mimic existing glass products. It is also desirable to measure various properties of the devices before and/or after treatment or coating.
Coating Deposited from an Organosilicon Precursor
A process is contemplated for applying a lubricity layer characterized as defined in the Definition Section on a substrate, for example the interior of the barrel of a syringe, comprising applying one of the described precursors on or in the vicinity of a substrate at a thickness of 1 to 5000 nm, optionally 10 to 1000 nm, optionally 10-200 nm, optionally 20 to 100 nm thick and crosslinking or polymerizing (or both) the coating, optionally in a PECVD process, to provide a lubricated surface. The coating applied by this process is also contemplated to be new.
A coating of SiwOxCyHz as defined in the Definition Section optionally can be very thin, having a thickness of at least 4 nm, or at least 7 nm, or at least 10 nm, or at least 20 nm, or at least 30 nm, or at least 40 nm, or at least 50 nm, or at least 100 nm, or at least 150 nm, or at least 200 nm, or at least 300 nm, or at least 400 nm, or at least 500 nm, or at least 600 nm, or at least 700 nm, or at least 800 nm, or at least 900 nm. The coating can be up to 1000 nm, or at most 900 nm, or at most 800 nm, or at most 700 nm, or at most 600 nm, or at most 500 nm, or at most 400 nm, or at most 300 nm, or at most 200 nm, or at most 100 nm, or at most 90 nm, or at most 80 nm, or at most 70 nm, or at most 60 nm, or at most 50 nm, or at most 40 nm, or at most 30 nm, or at most 20 nm, or at most 10 nm, or at most 5 nm thick. Specific thickness ranges composed of any one of the minimum thicknesses expressed above, plus any equal or greater one of the maximum thicknesses expressed above, are expressly contemplated.
Combinations of acid or base catalysis and heating, using an alkyl trimethoxysilane precursor as described above, can condense the precursor (removing ROH by-products) to form crosslinked polymers, which can optionally be further crosslinked via an alternative method. One specific example is by Shimojima et. al. J. Mater. Chem., 2007, 17, 658-663.
A lubricity layer, characterized as defined in the Definition Section, can be applied as a subsequent coating after applying an SiOx barrier layer to the interior surface 88 of the vessel 80 to provide a lubricity layer, particularly if the lubricity layer is a liquid organosiloxane compound at the end of the coating process.
Optionally, after the lubricity layer is applied, it can be post-cured after the PECVD process. Radiation curing approaches, including UV-initiated (free radial or cationic), electron-beam (E-beam), and thermal as described in Development Of Novel Cycloaliphatic Siloxanes For Thermal And UV-Curable Applications (Ruby Chakraborty Dissertation, can 2008) be utilized.
Another approach for providing a lubricity layer is to use a silicone demolding agent when injection-molding the thermoplastic vessel to be lubricated. For example, it is contemplated that any of the demolding agents and latent monomers causing in-situ thermal lubricity layer formation during the molding process can be used. Or, the aforementioned monomers can be doped into traditional demolding agents to accomplish the same result.
A lubricity layer, characterized as defined in the Definition Section, is particularly contemplated for the internal surface of a syringe barrel as further described below. A lubricated internal surface of a syringe barrel can reduce the plunger sliding force needed to advance a plunger in the barrel during operation of a syringe, or the breakout force to start a plunger moving after the prefilled syringe plunger has pushed away the intervening lubricant or adhered to the barrel, for example due to decomposition of the lubricant between the plunger and the barrel. As explained elsewhere in this specification, a lubricity layer also can be applied to the interior surface 88 of the vessel 80 to improve adhesion of a subsequent coating of SiOx.
Thus, the coating 90 can comprise a layer of SiOx and a lubricity layer, characterized as defined in the Definition Section. The lubricity layer of SiwOxCyHz can be deposited between the layer of SiOx and the interior surface of the vessel. Or, the layer of SiOx can be deposited between the lubricity layer and the interior surface of the vessel. Or, three or more layers, either alternating or graduated between these two coating compositions: (1) a layer of SiOx and (2) the lubricity layer; can also be used. The layer of SiOx can be deposited adjacent to the lubricity layer or remotely, with at least one intervening layer of another material. The layer of SiOx can be deposited adjacent to the interior surface of the vessel. Or, the lubricity layer can be deposited adjacent to the interior surface of the vessel.
Another expedient contemplated here, for adjacent layers of SiOx and a lubricity layer, is a graded composite of SiwOxCyHz, as defined in the Definition Section. A graded composite can be separate layers of a lubricity layer and SiOx with a transition or interface of intermediate composition between them, or separate layers of a lubricity layer and SiOx with an intermediate distinct layer of intermediate composition between them, or a single layer that changes continuously or in steps from a composition of a lubricity layer to a composition more like SiOx, going through the coating in a normal direction.
The grade in the graded composite can go in either direction. For example, the lubricity layer can be applied directly to the substrate and graduate to a composition further from the surface of SiOx. Or, the composition of SiOx can be applied directly to the substrate and graduate to a composition further from the surface of a lubricity layer. A graduated coating is particularly contemplated if a coating of one composition is better for adhering to the substrate than the other, in which case the better-adhering composition can, for example, be applied directly to the substrate. It is contemplated that the more distant portions of the graded coating can be less compatible with the substrate than the adjacent portions of the graded coating, since at any point the coating is changing gradually in properties, so adjacent portions at nearly the same depth of the coating have nearly identical composition, and more widely physically separated portions at substantially different depths can have more diverse properties. It is also contemplated that a coating portion that forms a better barrier against transfer of material to or from the substrate can be directly against the substrate, to prevent the more remote coating portion that forms a poorer barrier from being contaminated with the material intended to be barred or impeded by the barrier.
The coating, instead of being graded, optionally can have sharp transitions between one layer and the next, without a substantial gradient of composition. Such coatings can be made, for example, by providing the gases to produce a layer as a steady state flow in a non-plasma state, then energizing the system with a brief plasma discharge to form a coating on the substrate. If a subsequent coating is to be applied, the gases for the previous coating are cleared out and the gases for the next coating are applied in a steady-state fashion before energizing the plasma and again forming a distinct layer on the surface of the substrate or its outermost previous coating, with little if any gradual transition at the interface.
SiOx Barrier Coated Double Wall Plastic Vessel—COC, PET, SiOx Layers
Another embodiment is a vessel having a wall at least partially enclosing a lumen. The wall has an interior polymer layer enclosed by an exterior polymer layer. One of the polymer layers is a layer at least 0.1 mm thick of a cyclic olefin copolymer (COC) resin defining a water vapor barrier. Another of the polymer layers is a layer at least 0.1 mm thick of a polyester resin.
The wall includes an oxygen barrier layer of SiOx having a thickness of from about 10 to about 500 angstroms.
In an embodiment, illustrated in
As one example, the inner wall 408 can be made of PET coated on the interior surface 412 with an SiOx barrier layer, and the outer wall 410 can be made of COC. PET coated with SiOx, as shown elsewhere in this specification, is an excellent oxygen barrier, while COC is an excellent barrier for water vapor, providing a low water vapor transition rate (WVTR). This composite vessel can have superior barrier properties for both oxygen and water vapor. This construction is contemplated, for example, for an evacuated medical sample collection tube that contains an aqueous reagent as manufactured, and has a substantial shelf life, so it should have a barrier preventing transfer of water vapor outward or transfer of oxygen or other gases inward through its composite wall during its shelf life.
As another example, the inner wall 408 can be made of COC coated on the interior surface 412 with an SiOx barrier layer, and the outer wall 410 can be made of PET. This construction is contemplated, for example, for a prefilled syringe that contains an aqueous sterile fluid as manufactured. The SiOx barrier will prevent oxygen from entering the syringe through its wall. The COC inner wall will prevent ingress or egress of other materials such as water, thus preventing the water in the aqueous sterile fluid from leaching materials from the wall material into the syringe. The COC inner wall is also contemplated to prevent water derived from the aqueous sterile fluid from passing out of the syringe (thus undesirably concentrating the aqueous sterile fluid), and will prevent non-sterile water or other fluids outside the syringe from entering through the syringe wall and causing the contents to become non-sterile. The COC inner wall is also contemplated to be useful for decreasing the breaking force or friction of the plunger against the inner wall of a syringe.
Another embodiment is a method of making a vessel having a wall having an interior polymer layer enclosed by an exterior polymer layer, one layer made of COC and the other made of polyester. The vessel is made by a process including introducing COC and polyester resin layers into an injection mold through concentric injection nozzles.
An optional additional step is applying an amorphous carbon coating to the vessel by PECVD, as an inside coating, an outside coating, or as an interlayer coating located between the layers.
An optional additional step is applying an SiOx barrier layer to the inside of the vessel wall, where SiOx is defined as before. Another optional additional step is post-treating the SiOx layer with a process gas consisting essentially of oxygen and essentially free of a volatile silicon compound.
Optionally, the SiOx coating can be formed at least partially from a silazane feed gas.
The vessel 80 shown in
Or, the vessel 80 shown in
Or, the vessel 80 shown in
Another embodiment is a vessel including a barrier layer and a closure. The vessel is generally tubular and made of thermoplastic material. The vessel has a mouth and a lumen bounded at least in part by a wall having an inner surface interfacing with the lumen. There is an at least essentially continuous barrier layer made of glass on the inner surface of the wall. A closure covers the mouth and isolates the lumen of the vessel from ambient air.
The vessel 80 can also be made, for example of glass of any type used in medical or laboratory applications, such as soda-lime glass, borosilicate glass, or other glass formulations. Other vessels having any shape or size, made of any material, are also contemplated for use in the system 20. One function of coating a glass vessel can be to reduce the ingress of ions in the glass, either intentionally or as impurities, for example sodium, calcium, or others, from the glass to the contents of the vessel, such as a reagent or blood in an evacuated blood collection tube. Another function of coating a glass vessel in whole or in part, such as selectively at surfaces contacted in sliding relation to other parts, is to provide lubricity to the coating, for example to ease the insertion or removal of a stopper or passage of a sliding element such as a piston in a syringe. Still another reason to coat a glass vessel is to prevent a reagent or intended sample for the vessel, such as blood, from sticking to the wall of the vessel or an increase in the rate of coagulation of the blood in contact with the wall of the vessel.
A related embodiment is a vessel as described in the previous paragraph, in which the barrier layer is made of soda lime glass, borosilicate glass, or another type of glass.
Another embodiment is a method of applying a coating on an elastomeric stopper such as 282. The stopper 282, separate from the vessel 268, is placed in a substantially evacuated chamber. A reaction mixture is provided including plasma forming gas, i.e. an organosilicon compound gas, optionally an oxidizing gas, and optionally a hydrocarbon gas. Plasma is formed in the reaction mixture, which is contacted with the stopper. A lubricity, characterized as defined in the Definition Section, is deposited on at least a portion of the stopper.
In the illustrated embodiment, the wall-contacting surface 276 of the closure 270 is coated with a lubricity layer 286.
In some embodiments, the lubricity layer, characterized as defined in the Definition Section, is effective to reduce the transmission of one or more constituents of the stopper, such as a metal ion constituent of the stopper, or of the vessel wall, into the vessel lumen. Certain elastomeric compositions of the type useful for fabricating a stopper 282 contain trace amounts of one or more metal ions. These ions sometimes should not be able to migrate into the lumen 274 or come in substantial quantities into contact with the vessel contents, particularly if the sample vessel 268 is to be used to collect a sample for trace metal analysis. It is contemplated for example that coatings containing relatively little organic content, i.e. where y and z of SiwOxCyHz as defined in the Definition Section are low or zero, are particularly useful as a metal ion barrier in this application. Regarding silica as a metal ion barrier see, for example, Anupama Mallikarjunan, Jasbir Juneja, Guangrong Yang, Shyam P. Murarka, and Toh-Ming Lu, The Effect of Interfacial Chemistry on Metal Ion Penetration into Polymeric Films, Mat. Res. Soc. Symp. Proc., Vol. 734, pp. B9.60.1 to B9.60.6 (Materials Research Society, 2003); U.S. Pat. Nos. 5,578,103 and 6,200,658, and European Appl. EP0697378 A2, which are all incorporated here by reference. It is contemplated, however, that some organic content can be useful to provide a more elastic coating and to adhere the coating to the elastomeric surface of the stopper 282.
In some embodiments, the lubricity layer, characterized as defined in the Definition Section, can be a composite of material having first and second layers, in which the first or inner layer 288 interfaces with the elastomeric stopper 282 and is effective to reduce the transmission of one or more constituents of the stopper 282 into the vessel lumen. The second layer 286 can interface with the inner wall 280 of the vessel and is effective as a lubricity layer to reduce friction between the stopper 282 and the inner wall 280 of the vessel when the stopper 282 is seated on or in the vessel 268. Such composites are described in connection with syringe coatings elsewhere in this specification.
Or, the first and second layers 288 and 286 are defined by a coating of graduated properties, in which the values of y and z defined in the Definition Section are greater in the first layer than in the second layer.
The lubricity layer can be applied, for example, by PECVD substantially as previously described. The lubricity can be, for example, between 0.5 and 5000 nm (5 to 50,000 Angstroms) thick, or between 1 and 5000 nm thick, or between 5 and 5000 nm thick, or between 10 and 5000 nm thick, or between 20 and 5000 nm thick, or between 50 and 5000 nm thick, or between 100 and 5000 nm thick, or between 200 and 5000 nm thick, or between 500 and 5000 nm thick, or between 1000 and 5000 nm thick, or between 2000 and 5000 nm thick, or between 3000 and 5000 nm thick, or between 4000 and 10,000 nm thick.
Certain advantages are contemplated for plasma coated lubricity layers, versus the much thicker (one micron or greater) conventional spray applied silicone lubricants. Plasma coatings have a much lower migratory potential to move into blood versus sprayed or micron-coated silicones, both because the amount of plasma coated material is much less and because it can be more intimately applied to the coated surface and better bonded in place.
Nanocoatings, as applied by PECVD, are contemplated to offer lower resistance to sliding of an adjacent surface or flow of an adjacent fluid than micron coatings, as the plasma coating tends to provide a smoother surface.
Still another embodiment is a method of applying a coating of a lubricity on an elastomeric stopper. The stopper can be used, for example, to close the vessel previously described. The method includes several parts. A stopper is placed in a substantially evacuated chamber. A reaction mixture is provided comprising plasma forming gas, i.e. an organosilicon compound gas, optionally an oxidizing gas, and optionally a hydrocarbon gas. Plasma is formed in the reaction mixture. The stopper is contacted with the reaction mixture, depositing the coating of a lubricity on at least a portion of the stopper.
In practicing this method, to obtain higher values of y and z as defined in the Definition Section, it is contemplated that the reaction mixture can comprise a hydrocarbon gas, as further described above and below. Optionally, the reaction mixture can contain oxygen, if lower values of y and z or higher values of x are contemplated. Or, particularly to reduce oxidation and increase the values of y and z, the reaction mixture can be essentially free of an oxidizing gas.
In practicing this method to coat certain embodiments of the stopper such as the stopper 282, it is contemplated to be unnecessary to project the reaction mixture into the concavities of the stopper. For example, the wall-contacting and interior facing surfaces 276 and 272 of the stopper 282 are essentially convex, and thus readily treated by a batch process in which a multiplicity of stoppers such as 282 can be located and treated in a single substantially evacuated reaction chamber. It is further contemplated that in some embodiments the coatings 286 and 288 do not need to present as formidable a barrier to oxygen or water as the barrier layer on the interior surface 280 of the vessel 268, as the material of the stopper 282 can serve this function to a large degree.
Many variations of the stopper and the stopper coating process are contemplated. The stopper 282 can be contacted with the plasma. Or, the plasma can be formed upstream of the stopper 282, producing plasma product, and the plasma product can be contacted with the stopper 282. The plasma can be formed by exciting the reaction mixture with electromagnetic energy and/or microwave energy.
Variations of the reaction mixture are contemplated. The plasma forming gas can include an inert gas. The inert gas can be, for example, argon or helium, or other gases described in this disclosure. The organosilicon compound gas can be, or include, HMDSO, OMCTS, any of the other organosilicon compounds mentioned in this disclosure, or a combination of two or more of these. The oxidizing gas can be oxygen or the other gases mentioned in this disclosure, or a combination of two or more of these. The hydrocarbon gas can be, for example, methane, methanol, ethane, ethylene, ethanol, propane, propylene, propanol, acetylene, or a combination of two or more of these.
Another embodiment is a method of applying a coating of a composition including carbon and one or more elements of Groups III or IV on an elastomeric stopper. To carry out the method, a stopper is located in a deposition chamber.
A reaction mixture is provided in the deposition chamber, including a plasma forming gas with a gaseous source of a Group III element, a Group IV element, or a combination of two or more of these. The reaction mixture optionally contains an oxidizing gas and optionally contains a gaseous compound having one or more C—H bonds. Plasma is formed in the reaction mixture, and the stopper is contacted with the reaction mixture. A coating of a Group III element or compound, a Group IV element or compound, or a combination of two or more of these is deposited on at least a portion of the stopper.
Another embodiment is a vessel including a barrier layer and a closure. The vessel is generally tubular and made of thermoplastic material. The vessel has a mouth and a lumen bounded at least in part by a wall. The wall has an inner surface interfacing with the lumen. An at least essentially continuous barrier layer is applied on the inner surface of the wall. The barrier layer is effective to provide a substantial shelf life. A closure is provided covering the mouth of the vessel and isolating the lumen of the vessel from ambient air.
Referring to
The vessel is, in this embodiment, a generally tubular vessel having an at least essentially continuous barrier layer and a closure. The vessel is made of thermoplastic material having a mouth and a lumen bounded at least in part by a wall having an inner surface interfacing with the lumen. The barrier layer is deposited on the inner surface of the wall, and is effective to maintain at least 95%, or at least 90%, of the initial vacuum level of the vessel for a shelf life of at least 24 months, optionally at least 30 months, optionally at least 36 months. The closure covers the mouth of the vessel and isolates the lumen of the vessel from ambient air.
The closure, for example the closure 270 illustrated in the Figures or another type of closure, is provided to maintain a partial vacuum and/or to contain a sample and limit or prevent its exposure to oxygen or contaminants.
The closure 270 comprises a interior-facing surface 272 exposed to the lumen 274 of the vessel 268 and a wall-contacting surface 276 that is in contact with the inner surface 278 of the vessel wall 280. In the illustrated embodiment the closure 270 is an assembly of a stopper 282 and a shield 284.
In the illustrated embodiment, the stopper 282 defines the wall-contacting surface 276 and the inner surface 278, while the shield is largely or entirely outside the stoppered vessel 268, retains and provides a grip for the stopper 282, and shields a person removing the closure 270 from being exposed to any contents expelled from the vessel 268, such as due to a pressure difference inside and outside of the vessel 268 when the vessel 268 is opened and air rushes in or out to equalize the pressure difference.
It is further contemplated that the coatings on the vessel wall 280 and the wall contacting surface 276 of the stopper can be coordinated. The stopper can be coated with a lubricity silicone layer, and the vessel wall 280, made for example of PET or glass, can be coated with a harder SiOx layer, or with an underlying SiOx layer and a lubricity overcoat.
The foregoing description has largely addressed applying a barrier layer to a tube with one permanently closed end, such as a blood collection tube or, more generally, a specimen receiving tube 80. The apparatus is not limited to such a device.
Another example of a suitable vessel, shown in
A syringe barrel 250 as molded commonly can be open at both the back end 256, to receive a plunger 258, and at the front end 260, to receive a hypodermic needle, a nozzle, or tubing for dispensing the contents of the syringe 252 or for receiving material into the syringe 252. But the front end 260 can optionally be capped and the plunger 258 optionally can be fitted in place before the prefilled syringe 252 is used, closing the barrel 250 at both ends. A cap 262 can be installed either for the purpose of processing the syringe barrel 250 or assembled syringe, or to remain in place during storage of the prefilled syringe 252, up to the time the cap 262 is removed and (optionally) a hypodermic needle or other delivery conduit is fitted on the front end 260 to prepare the syringe 252 for use.
The installation of a cap 262 makes the barrel 250 a closed-end vessel that can be provided with an SiOx barrier or other type of coating on its interior surface 254 in the previously illustrated apparatus, optionally also providing a coating on the interior 264 of the cap and bridging the interface between the cap interior 264 and the barrel front end 260. Suitable apparatus adapted for this use is shown, for example, in
Syringe Having Barrel Coated with Lubricity Layer Deposited from an Organosilicon Precursor
Still another embodiment is a vessel having a lubricity layer, characterized as defined in the Definition Section, of the type made by the following process.
A precursor is provided as defined above.
The precursor is applied to a substrate under conditions effective to form a coating. The coating is polymerized or crosslinked, or both, to form a lubricated surface having a lower plunger sliding force or breakout force than the untreated substrate.
Optionally, the applying step is carried out by vaporizing the precursor and providing it in the vicinity of the substrate.
Respecting any of the Embodiments i, optionally a plasma, optionally a non-hollow-cathode plasma, is formed in the vicinity of the substrate. Optionally, the precursor is provided in the substantial absence of oxygen. Optionally, the precursor is provided in the substantial absence of a carrier gas. Optionally, the precursor is provided in the substantial absence of nitrogen. Optionally, the precursor is provided at less than 1 Torr absolute pressure. Optionally, the precursor is provided to the vicinity of a plasma emission. Optionally, the precursor its reaction product is applied to the substrate at a thickness of 1 to 5000 nm thick, or 10 to 1000 nm thick, or 10-200 nm thick, or 20 to 100 nm thick. Optionally, the substrate comprises glass. Optionally, the substrate comprises a polymer, optionally a polycarbonate polymer, optionally an olefin polymer, optionally a cyclic olefin copolymer, optionally a polypropylene polymer, optionally a polyester polymer, optionally a polyethylene terephthalate polymer.
Optionally, the plasma is generated by energizing the gaseous reactant containing the precursor with electrodes powered, for example, at a RF frequency as defined above, for example a frequency of from 10 kHz to less than 300 MHz, optionally from 1 to 50 MHz, even optionally from 10 to 15 MHz, optionally a frequency of 13.56 MHz.
Optionally, the plasma is generated by energizing the gaseous reactant containing the precursor with electrodes supplied with an electric power of from 0.1 to 25 W, optionally from 1 to 22 W, optionally from 3 to 17 W, even optionally from 5 to 14 W, optionally from 7 to 11 W, optionally 8 W. The ratio of the electrode power to the plasma volume can be less than 10 W/ml, optionally is from 5 W/ml to 0.1 W/ml, optionally is from 4 W/ml to 0.1 W/ml, optionally from 2 W/ml to 0.2 W/ml. These power levels are suitable for applying lubricity layers to syringes and sample tubes and vessels of similar geometry having a void volume of 1 to 3 mL in which PECVD plasma is generated. It is contemplated that for larger or smaller objects the power applied should be increased or reduced accordingly to scale the process to the size of the substrate.
Another embodiment is a lubricity layer, characterized as defined in the Definition Section, on the inner wall of a syringe barrel. The coating is produced from a PECVD process using the following materials and conditions. A cyclic precursor is optionally employed, selected from a monocyclic siloxane, a polycyclic siloxane, or a combination of two or more of these, as defined elsewhere in this specification for lubricity layers. One example of a suitable cyclic precursor comprises octamethylcyclotetrasiloxane (OMCTS), optionally mixed with other precursor materials in any proportion. Optionally, the cyclic precursor consists essentially of octamethylcyclotetrasiloxane (OMCTS), meaning that other precursors can be present in amounts which do not change the basic and novel properties of the resulting lubricity layer, i.e. its reduction of the plunger sliding force or breakout force of the coated surface.
Optionally, at least essentially no oxygen, as defined in the Definition Section is added to the process.
A sufficient plasma generation power input, for example any power level successfully used in one or more working examples of this specification or described in the specification, is provided to induce coating formation.
The materials and conditions employed are effective to reduce the syringe plunger sliding force or breakout force moving through the syringe barrel at least 25 percent, alternatively at least 45 percent, alternatively at least 60 percent, alternatively greater than 60 percent, relative to an uncoated syringe barrel. Ranges of plunger sliding force or breakout force reduction of from 20 to 95 percent, alternatively from 30 to 80 percent, alternatively from 40 to 75 percent, alternatively from 60 to 70 percent, are contemplated.
Respecting any of the embodiments, optionally the substrate comprises glass or a polymer. The glass optionally is borosilicate glass. The polymer is optionally a polycarbonate polymer, optionally an olefin polymer, optionally a cyclic olefin copolymer, optionally a polypropylene polymer, optionally a polyester polymer, optionally a polyethylene terephthalate polymer.
Another embodiment is a syringe including a plunger, a syringe barrel, and a lubricity layer, characterized as defined in the Definition Section. The syringe barrel includes an interior surface receiving the plunger for sliding. The lubricity layer is disposed on the interior surface of the syringe barrel. The lubricity layer is less than 1000 nm thick and effective to reduce the breakout force or the plunger sliding force necessary to move the plunger within the barrel. Reducing the plunger sliding force is alternatively expressed as reducing the coefficient of sliding friction of the plunger within the barrel or reducing the plunger force; these terms are regarded as having the same meaning in this specification.
Any of the above precursors of any type can be used alone or in combinations of two or more of them to provide a lubricity layer.
In addition to utilizing vacuum processes, low temperature atmospheric (non-vacuum) plasma processes can also be utilized to induce molecular ionization and deposition through precursor monomer vapor delivery optionally in a non-oxidizing atmosphere such as helium or argon. Separately, thermal CVD can be considered via flash thermolysis deposition.
The approaches above are similar to vacuum PECVD in that the surface coating and crosslinking mechanisms can occur simultaneously.
Yet another expedient contemplated for any coating or coatings described here is a coating that is not uniformly applied over the entire interior 88 of a vessel. For example, a different or additional coating can be applied selectively to the cylindrical portion of the vessel interior, compared to the hemispherical portion of the vessel interior at its closed end 84, or vice versa. This expedient is particularly contemplated for a syringe barrel or a sample collection tube as described below, in which a lubricity layer might be provided on part or all of the cylindrical portion of the barrel, where the plunger or piston or closure slides, and not elsewhere.
Optionally, the precursor can be provided in the presence, substantial absence, or absence of oxygen, in the presence, substantial absence, or absence of nitrogen, or in the presence, substantial absence, or absence of a carrier gas. In one contemplated embodiment, the precursor alone is delivered to the substrate and subjected to PECVD to apply and cure the coating.
Optionally, the precursor can be provided at less than 1 Torr absolute pressure.
Optionally, the precursor can be provided to the vicinity of a plasma emission.
Optionally, the precursor or its reaction product can be applied to the substrate at a thickness of 1 to 5000 nm, or 10 to 1000 nm, or 10-200 nm, or 20 to 100 nm.
In any of the above embodiments, the substrate can comprise glass, or a polymer, for example one or more of a polycarbonate polymer, an olefin polymer (for example a cyclic olefin copolymer or a polypropylene polymer), or a polyester polymer (for example, a polyethylene terephthalate polymer).
In any of the above embodiments, the plasma is generated by energizing the gaseous reactant containing the precursor with electrodes powered at a RF frequency as defined in this description.
In any of the above embodiments, the plasma is generated by energizing the gaseous reactant containing the precursor with electrodes supplied with sufficient electric power to generate a lubricity layer. Optionally, the plasma is generated by energizing the gaseous reactant containing the precursor with electrodes supplied with an electric power of from 0.1 to 25 W, optionally from 1 to 22 W, optionally from 3 to 17 W, even optionally from 5 to 14 W, optionally from 7 to 11 W, optionally 8 W. The ratio of the electrode power to the plasma volume can be less than 10 W/ml, optionally is from 5 W/ml to 0.1 W/ml, optionally is from 4 W/ml to 0.1 W/ml, optionally from 2 W/ml to 0.2 W/ml. These power levels are suitable for applying lubricity layers to syringes and sample tubes and vessels of similar geometry having a void volume of 1 to 3 mL in which PECVD plasma is generated. It is contemplated that for larger or smaller objects the power applied should be increased or reduced accordingly to scale the process to the size of the substrate.
The coating can be cured, as by polymerizing or crosslinking the coating, or both, to form a lubricated surface having a lower plunger sliding force or breakout force than the untreated substrate. Curing can occur during the application process such as PECVD, or can be carried out or at least completed by separate processing.
Although plasma deposition has been used herein to demonstrate the coating characteristics, alternate deposition methods can be used as long as the chemical composition of the starting material is preserved as much as possible while still depositing a solid film that is adhered to the base substrate.
For example, the coating material can be applied onto the syringe barrel (from the liquid state) by spraying the coating or dipping the substrate into the coating, where the coating is either the neat precursor a solvent-diluted precursor (allowing the mechanical deposition of a thinner coating). The coating optionally can be crosslinked using thermal energy, UV energy, electron beam energy, plasma energy, or any combination of these.
Application of a silicone precursor as described above onto a surface followed by a separate curing step is also contemplated. The conditions of application and curing can be analogous to those used for the atmospheric plasma curing of pre-coated polyfluoroalkyl ethers, a process practiced under the trademark TriboGlide®. More details of this process can be found at http://www.triboglide.com/process.htm.
In such a process, the area of the part to be coated can optionally be pre-treated with an atmospheric plasma. This pretreatment cleans and activates the surface so that it is receptive to the lubricant that is sprayed in the next step.
The lubrication fluid, in this case one of the above precursors or a polymerized precursor, is then sprayed on to the surface to be treated. For example, IVEK precision dispensing technology can be used to accurately atomize the fluid and create a uniform coating.
The coating is then bonded or crosslinked to the part, again using an atmospheric plasma field. This both immobilizes the coating and improves the lubricant's performance.
Optionally, the atmospheric plasma can be generated from ambient air in the vessel, in which case no gas feed and no vacuum drawing equipment is needed. Optionally, however, the vessel is at least substantially closed while plasma is generated, to minimize the power requirement and prevent contact of the plasma with surfaces or materials outside the vessel.
Another embodiment is a syringe comprising a barrel defining a lumen and having an interior surface slidably receiving a plunger, i.e. receiving a plunger for sliding contact to the interior surface.
The syringe barrel is made of thermoplastic base material.
Optionally, the interior surface of the barrel is coated with an SiOx barrier layer as described elsewhere in this specification.
A lubricity layer is applied to the barrel interior surface, the plunger, or both, or to the previously applied SiOx barrier layer. The lubricity layer can be provided, applied, and cured as set out in this specification.
For example, the lubricity layer can be applied, in any embodiment, by PECVD. The lubricity layer is deposited from an organosilicon precursor, and is less than 1000 nm thick.
A surface treatment is carried out on the lubricity layer in an amount effective to reduce the leaching or extractables of the lubricity layer, the thermoplastic base material, or both. The treated surface can thus act as a solute retainer. This surface treatment can result in a skin coating, e.g. a skin coating which is at least 1 nm thick and less than 100 nm thick, or less than 50 nm thick, or less than 40 nm thick, or less than 30 nm thick, or less than 20 nm thick, or less than 10 nm thick, or less than 5 nm thick, or less than 3 nm thick, or less than 2 nm thick, or less than 1 nm thick, or less than 0.5 nm thick.
As used herein, “leaching” refers to material transferred out of a substrate, such as a vessel wall, into the contents of a vessel, for example a syringe. Commonly, leachables are measured by storing the vessel filled with intended contents, then analyzing the contents to determine what material leached from the vessel wall into the intended contents. “Extraction” refers to material removed from a substrate by introducing a solvent or dispersion medium other than the intended contents of the vessel, to determine what material can be removed from the substrate into the extraction medium under the conditions of the test.
The surface treatment resulting in a solute retainer optionally can be a SiOx layer as previously defined in this specification, characterized as defined in the Definition Section. In one embodiment, the surface treatment can be applied by PECVD deposit of SiOx. Optionally, the surface treatment can be applied using higher power or stronger oxidation conditions than used for creating the lubricity layer, or both, thus providing a harder, thinner, continuous solute retainer 539. Surface treatment can be less than 100 nm deep, optionally less than 50 nm deep, optionally less than 40 nm deep, optionally less than 30 nm deep, optionally less than 20 nm deep, optionally less than 10 nm deep, optionally less than 5 nm deep, optionally less than 3 nm deep, optionally less than 1 nm deep, optionally less than 0.5 nm deep, optionally between 0.1 and 50 nm deep in the lubricity layer.
The solute retainer is contemplated to provide low solute leaching performance to the underlying lubricity and other layers, including the substrate, as required. This retainer would only need to be a solute retainer to large solute molecules and oligomers (for example siloxane monomers such as HMDSO, OMCTS, their fragments and mobile oligomers derived from lubricants, for example a “leachables retainer”) and not a gas (O2/N2/CO2/water vapor) barrier layer. A solute retainer can, however, also be a gas barrier (e.g. the SiOx coating according to present invention. One can create a good leachable retainer without gas barrier performance, either by vacuum or atmospheric-based PECVD processes. It is desirable that the “leachables barrier” will be sufficiently thin that, upon syringe plunger movement, the plunger will readily penetrate the “solute retainer” exposing the sliding plunger nipple to the lubricity layer immediately below to form a lubricated surface having a lower plunger sliding force or breakout force than the untreated substrate.
In another embodiment, the surface treatment can be performed by oxidizing the surface of a previously applied lubricity layer, as by exposing the surface to oxygen in a plasma environment. The plasma environment described in this specification for forming SiOx coatings can be used. Or, atmospheric plasma conditions can be employed in an oxygen-rich environment.
The lubricity layer and solute retainer, however formed, optionally can be cured at the same time. In another embodiment, the lubricity layer can be at least partially cured, optionally fully cured, after which the surface treatment can be provided, applied, and the solute retainer can be cured.
The lubricity layer and solute retainer are composed, and present in relative amounts, effective to provide a breakout force, plunger sliding force, or both that is less than the corresponding force required in the absence of the lubricity layer and surface treatment. In other words, the thickness and composition of the solute retainer are such as to reduce the leaching of material from the lubricity layer into the contents of the syringe, while allowing the underlying lubricity layer to lubricate the plunger. It is contemplated that the solute retainer will break away easily and be thin enough that the lubricity layer will still function to lubricate the plunger when it is moved.
In one contemplated embodiment, the lubricity and surface treatments can be applied on the barrel interior surface. In another contemplated embodiment, the lubricity and surface treatments can be applied on the plunger. In still another contemplated embodiment, the lubricity and surface treatments can be applied both on the barrel interior surface and on the plunger. In any of these embodiments, the optional SiOx barrier layer on the interior of the syringe barrel can either be present or absent.
One embodiment contemplated is a plural-layer, e.g. a 3-layer, configuration applied to the inside surface of a syringe barrel. Layer 1 can be an SiOx gas barrier made by PECVD of HMDSO, OMCTS, or both, in an oxidizing atmosphere. Such an atmosphere can be provided, for example, by feeding HMDSO and oxygen gas to a PECVD coating apparatus as described in this specification. Layer 2 can be a lubricity layer using OMCTS applied in a non-oxidizing atmosphere. Such a non-oxidizing atmosphere can be provided, for example, by feeding OMCTS to a PECVD coating apparatus as described in this specification, optionally in the substantial or complete absence of oxygen. A subsequent solute retainer can be formed by a treatment forming a thin skin layer of SiOx as a solute retainer using higher power and oxygen using OMCTS and/or HMDSO.
Certain of these plural-layer coatings are contemplated to have one or more of the following optional advantages, at least to some degree. They can address the reported difficulty of handling silicone, since the solute retainer can confine the interior silicone and prevent it from migrating into the contents of the syringe or elsewhere, resulting in fewer silicone particles in the deliverable contents of the syringe and less opportunity for interaction between the lubricity layer and the contents of the syringe. They can also address the issue of migration of the lubricity layer away from the point of lubrication, improving the lubricity of the interface between the syringe barrel and the plunger. For example, the break-free force can be reduced and the drag on the moving plunger can be reduced, or optionally both.
It is contemplated that when the solute retainer is broken, the solute retainer will continue to adhere to the lubricity layer and the syringe barrel, which can inhibit any particles from being entrained in the deliverable contents of the syringe.
Certain of these coatings will also provide manufacturing advantages, particularly if the barrier layer, lubricity layer and surface treatment are applied in the same apparatus, for example the illustrated PECVD apparatus. Optionally, the SiOx barrier layer, lubricity layer, and surface treatment can all be applied in one PECVD apparatus, thus greatly reducing the amount of handling necessary.
Further advantages can be obtained by forming the barrier layer, lubricity layer, and solute retainer using the same precursors and varying the process. For example, an SiOx gas barrier layer can be applied using an OMCTS precursor under high power/high O2 conditions, followed by applying a lubricity layer applied using an OMCTS precursor under low power and/or in the substantial or complete absence of oxygen, finishing with a surface treatment using an OMCTS precursor under intermediate power and oxygen.
Syringe Having Barrel with SiOx Coated Interior and Barrier Coated Exterior
In any embodiment, the thermoplastic base material optionally can include a polyolefin, for example polypropylene or a cyclic olefin copolymer (for example the material sold under the trademark TOPAS®), a polyester, for example polyethylene terephthalate, a polycarbonate, for example a bisphenol A polycarbonate thermoplastic, or other materials. Composite syringe barrels are contemplated having any one of these materials as an outer layer and the same or a different one of these materials as an inner layer. Any of the material combinations of the composite syringe barrels or sample tubes described elsewhere in this specification can also be used.
In any embodiment, the resin optionally can include polyvinylidene chloride in homopolymer or copolymer form. For example, the PVdC homopolymers (trivial name: Saran) or copolymers described in U.S. Pat. No. 6,165,566, incorporated here by reference, can be employed. The resin optionally can be applied onto the exterior surface of the barrel in the form of a latex or other dispersion.
In any embodiment, the syringe barrel 548 optionally can include a lubricity layer disposed between the plunger and the barrier layer of SiOx. Suitable lubricity layers are described elsewhere in this specification.
In any embodiment, the lubricity layer optionally can be applied by PECVD and optionally can include material characterized as defined in the Definition Section.
In any embodiment, the syringe barrel 548 optionally can include a surface treatment covering the lubricity layer in an amount effective to reduce the leaching of the lubricity layer, constituents of the thermoplastic base material, or both into the lumen 604.
Method of Making Syringe Having Barrel with SiOx Coated Interior and Barrier Coated Exterior
Even another embodiment is a method of making a syringe as described in any of the embodiments of this specification, including a plunger, a barrel, and interior and exterior barrier layers. A barrel is provided having an interior surface for receiving the plunger for sliding and an exterior surface. A barrier layer of SiOx is provided on the interior surface of the barrel by PECVD. A barrier layer of a resin is provided on the exterior surface of the barrel. The plunger and barrel are assembled to provide a syringe.
For effective coating (uniform wetting) of the plastic article with the aqueous latex, it is contemplated to be useful to match the surface tension of the latex to the plastic substrate. This can be accomplished by several approaches, independently or combined, for example, reducing the surface tension of the latex (with surfactants or solvents), and/or corona pretreatment of the plastic article, and/or chemical priming of the plastic article.
The resin optionally can be applied via dip coating of the latex onto the exterior surface of the barrel, spray coating of the latex onto the exterior surface of the barrel, or both, providing plastic-based articles offering improved gas and vapor barrier performance. Polyvinylidene chloride plastic laminate articles can be made that provide significantly improved gas barrier performance versus the non-laminated plastic article.
In any embodiment, the resin optionally can be heat cured. The resin optionally can be cured by removing water. Water can be removed by heat curing the resin, exposing the resin to a partial vacuum or low-humidity environment, catalytically curing the resin, or other expedients.
An effective thermal cure schedule is contemplated to provide final drying to permit PVdC crystallization, offering barrier performance. Primary curing can be carried out at an elevated temperature, for example between 180-310.degree. F. (82-154.degree. C.), of course depending on the heat tolerance of the thermoplastic base material. Barrier performance after the primary cure optionally can be about 85% of the ultimate barrier performance achieved after a final cure.
A final cure can be carried out at temperatures ranging from ambient temperature, such as about 65-75.degree. F. (18-24.degree. C.) for a long time (such as 2 weeks) to an elevated temperature, such as 122.degree. F. (50.degree. C.), for a short time, such as four hours.
The PVdC-plastic laminate articles, in addition to superior barrier performance, are optionally contemplated to provide one or more desirable properties such as colorless transparency, good gloss, abrasion resistance, printability, and mechanical strain resistance.
Plungers with Barrier Coated Piston Front Face
Another embodiment is a plunger for a syringe, including a piston and a push rod. The piston has a front face, a generally cylindrical side face, and a back portion, the side face being configured to movably seat within a syringe barrel. The front face has a barrier layer. The push rod engages the back portion and is configured for advancing the piston in a syringe barrel.
With Lubricity Layer Interfacing with Side Face
Yet another embodiment is a plunger for a syringe, including a piston, a lubricity layer, and a push rod. The piston has a front face, a generally cylindrical side face, and a back portion. The side face is configured to movably seat within a syringe barrel. The lubricity layer interfaces with the side face. The push rod engages the back portion of the piston and is configured for advancing the piston in a syringe barrel.
Another embodiment is a syringe including a plunger, a syringe barrel, and a Luer fitting. The syringe includes a barrel having an interior surface receiving the plunger for sliding. The Luer fitting includes a Luer taper having an internal passage defined by an internal surface. The Luer fitting is formed as a separate piece from the syringe barrel and joined to the syringe barrel by a coupling. The internal passage of the Luer taper has a barrier layer of SiOx.
Lubricant Compositions—Lubricity Layer Deposited from an Organosilicon Precursor Made by In Situ Polymerizing Organosilicon Precursor—Product by Process—and Lubricity
Still another embodiment is a lubricity layer. This coating can be of the type made by the following process.
Any of the precursors mentioned elsewhere in this specification can be used, alone or in combination. The precursor is applied to a substrate under conditions effective to form a coating. The coating is polymerized or crosslinked, or both, to form a lubricated surface having a lower plunger sliding force or breakout force than the untreated substrate.
Another embodiment is a method of applying a lubricity layer. An organosilicon precursor is applied to a substrate under conditions effective to form a coating. The coating is polymerized or crosslinked, or both, to form a lubricated surface having a lower plunger sliding force or breakout force than the untreated substrate.
Even another aspect of the invention is a lubricity layer deposited by PECVD from a feed gas comprising an organometallic precursor, optionally an organosilicon precursor, optionally a linear siloxane, a linear silazane, a monocyclic siloxane, a monocyclic silazane, a polycyclic siloxane, a polycyclic silazane, or any combination of two or more of these. The coating has a density between 1.25 and 1.65 g/cm3 optionally between 1.35 and 1.55 g/cm3, optionally between 1.4 and 1.5 g/cm3, optionally between 1.44 and 1.48 g/cm3 as determined by X-ray reflectivity (XRR).
Still another aspect of the invention is a lubricity layer deposited by PECVD from a feed gas comprising an organometallic precursor, optionally an organosilicon precursor, optionally a linear siloxane, a linear silazane, a monocyclic siloxane, a monocyclic silazane, a polycyclic siloxane, a polycyclic silazane, or any combination of two or more of these. The coating has as an outgas component one or more oligomers containing repeating -(Me)2SiO— moieties, as determined by gas chromatography/mass spectrometry. Optionally, the coating meets the limitations of any of embodiments shown. Optionally, the coating outgas component as determined by gas chromatography/mass spectrometry is substantially free of trimethylsilanol.
Optionally, the coating outgas component can be at least 10 ng/test of oligomers containing repeating -(Me)2SiO— moieties, as determined by gas chromatography/mass spectrometry using the following test conditions:
Optionally, the outgas component can include at least 20 ng/test of oligomers containing repeating -(Me)2SiO— moieties.
Optionally, the feed gas comprises a monocyclic siloxane, a monocyclic silazane, a polycyclic siloxane, a polycyclic silazane, or any combination of two or more of these, for example a monocyclic siloxane, a monocyclic silazane, or any combination of two or more of these, for example octamethylcyclotetrasiloxane.
The lubricity layer of any embodiment can have a thickness measured by transmission electron microscopy (TEM) between 1 and 500 nm, optionally between 10 and 500 nm, optionally between 20 and 200 nm, optionally between 20 and 100 nm, optionally between 30 and 100 nm.
Another aspect of the invention is a lubricity layer deposited by PECVD from a feed gas comprising a monocyclic siloxane, a monocyclic silazane, a polycyclic siloxane, a polycyclic silazane, or any combination of two or more of these. The coating has an atomic concentration of carbon, normalized to 100% of carbon, oxygen, and silicon, as determined by X-ray photoelectron spectroscopy (XPS), greater than the atomic concentration of carbon in the atomic formula for the feed gas. Optionally, the coating meets the limitations of any embodiments.
Optionally, the atomic concentration of carbon increases by from 1 to 80 atomic percent (as calculated and based on the XPS conditions in Example 9), alternatively from 10 to 70 atomic percent, alternatively from 20 to 60 atomic percent, alternatively from 30 to 50 atomic percent, alternatively from 35 to 45 atomic percent, alternatively from 37 to 41 atomic percent.
An additional aspect of the invention is a lubricity layer deposited by PECVD from a feed gas comprising a monocyclic siloxane, a monocyclic silazane, a polycyclic siloxane, a polycyclic silazane, or any combination of two or more of these. The coating has an atomic concentration of silicon, normalized to 100% of carbon, oxygen, and silicon, as determined by X-ray photoelectron spectroscopy (XPS), less than the atomic concentration of silicon in the atomic formula for the feed gas. Optionally, the coating meets the limitations of any embodiments.
Optionally, the atomic concentration of silicon decreases by from 1 to 80 atomic percent (as calculated and based on the XPS conditions in Example 9), alternatively from 10 to 70 atomic percent, alternatively from 20 to 60 atomic percent, alternatively from 30 to 55 atomic percent, alternatively from 40 to 50 atomic percent, alternatively from 42 to 46 atomic percent.
Lubricity layers having combinations of any two or more properties recited in this specification are also expressly contemplated.
A coated vessel or container as described herein and/or prepared according to a method described herein can be used for reception and/or storage and/or delivery of a compound or composition. The compound or composition can be sensitive, for example air-sensitive, oxygen-sensitive, sensitive to humidity and/or sensitive to mechanical influences. It can be a biologically active compound or composition, for example a medicament like insulin or a composition comprising insulin. In another aspect, it can be a biological fluid, optionally a bodily fluid, for example blood or a blood fraction. In certain aspects of the present invention, the compound or composition is a product to be administrated to a subject in need thereof, for example a product to be injected, like blood (as in transfusion of blood from a donor to a recipient or reintroduction of blood from a patient back to the patient) or insulin.
A coated vessel or container as described herein and/or prepared according to a method described herein can further be used for protecting a compound or composition contained in its interior space against mechanical and/or chemical effects of the surface of the uncoated vessel material. For example, it can be used for preventing or reducing precipitation and/or clotting or platelet activation of the compound or a component of the composition, for example insulin precipitation or blood clotting or platelet activation.
It can further be used for protecting a compound or composition contained in its interior against the environment outside of the vessel, for example by preventing or reducing the entry of one or more compounds from the environment surrounding the vessel into the interior space of the vessel. Such environmental compound can be a gas or liquid, for example an atmospheric gas or liquid containing oxygen, air, and/or water vapor.
A coated vessel as described herein can also be evacuated and stored in an evacuated state. For example, the coating allows better maintenance of the vacuum in comparison to a corresponding uncoated vessel. In one aspect of this embodiment, the coated vessel is a blood collection tube. The tube can also contain an agent for preventing blood clotting or platelet activation, for example EDTA or heparin.
Any of the above-described embodiments can be made, for example, by providing as the vessel a length of tubing from about 1 cm to about 200 cm, optionally from about 1 cm to about 150 cm, optionally from about 1 cm to about 120 cm, optionally from about 1 cm to about 100 cm, optionally from about 1 cm to about 80 cm, optionally from about 1 cm to about 60 cm, optionally from about 1 cm to about 40 cm, optionally from about 1 cm to about 30 cm long, and processing it with a probe electrode as described below. Particularly for the longer lengths in the above ranges, it is contemplated that relative motion between the probe and the vessel can be useful during coating formation. This can be done, for example, by moving the vessel with respect to the probe or moving the probe with respect to the vessel.
In these embodiments, it is contemplated that the coating can be thinner or less complete than can be preferred for a barrier layer, as the vessel in some embodiments will not require the high barrier integrity of an evacuated blood collection tube.
As an optional feature of any of the foregoing embodiments the vessel has a central axis.
As an optional feature of any of the foregoing embodiments the vessel wall is sufficiently flexible to be flexed at least once at 20.degree. C., without breaking the wall, over a range from at least substantially straight to a bending radius at the central axis of not more than 100 times as great as the outer diameter of the vessel.
As an optional feature of any of the foregoing embodiments the bending radius at the central axis is not more than 90 times as great as, or not more than 80 times as great as, or not more than 70 times as great as, or not more than 60 times as great as, or not more than 50 times as great as, or not more than 40 times as great as, or not more than 30 times as great as, or not more than 20 times as great as, or not more than 10 times as great as, or not more than 9 times as great as, or not more than 8 times as great as, or not more than 7 times as great as, or not more than 6 times as great as, or not more than 5 times as great as, or not more than 4 times as great as, or not more than 3 times as great as, or not more than 2 times as great as, or not more than, the outer diameter of the vessel.
As an optional feature of any of the foregoing embodiments the vessel wall can be a fluid-contacting surface made of flexible material.
As an optional feature of any of the foregoing embodiments the vessel lumen can be the fluid flow passage of a pump.
As an optional feature of any of the foregoing embodiments the vessel can be a blood bag adapted to maintain blood in good condition for medical use.
As an optional feature of any of the foregoing embodiments the polymeric material can be a silicone elastomer or a thermoplastic polyurethane, as two examples, or any material suitable for contact with blood, or with insulin.
In an optional embodiment, the vessel has an inner diameter of at least 2 mm, or at least 4 mm.
As an optional feature of any of the foregoing embodiments the vessel is a tube.
As an optional feature of any of the foregoing embodiments the lumen has at least two open ends.
Another embodiment is a blood containing vessel having a wall having an inner surface defining a lumen. The inner surface has an at least partial coating of a composition comprising one or more elements of Group III, one or more elements of Group IV, or a combination of two or more of these. The thickness of the coating is between monomolecular thickness and about 1000 nm thick, inclusive, on the inner surface. The vessel contains blood viable for return to the vascular system of a patient disposed within the lumen in contact with the layer.
Optionally, in the vessel of the preceding paragraph, the coating of the Group III or IV Element is effective to reduce the clotting or platelet activation of blood exposed to the inner surface of the vessel wall.
A coated vessel or container as described herein can be used for preventing or reducing the escape of a compound or composition contained in the vessel into the environment surrounding the vessel.
Further uses of the coating and vessel as described herein, which are apparent from any part of the description and claims, are also contemplated.
Another embodiment is an insulin containing vessel including a wall having an inner surface defining a lumen. The inner surface has an at least partial coating of a composition comprising carbon, one or more elements of Group III, one or more elements of Group IV, or a combination of two or more of these. The coating can be from monomolecular thickness to about 1000 nm thick on the inner surface. Insulin is disposed within the lumen in contact with the coating.
Optionally, in the vessel of the preceding paragraph, the coating of a composition comprising carbon, one or more elements of Group III, one or more elements of Group IV, or a combination of two or more of these, is effective to reduce the formation of a precipitate from insulin contacting the inner surface, compared to the same surface absent the coating.
The vessels tested in the subsequent working examples were formed and coated according to the following exemplary protocols, except as otherwise indicated in individual examples. Particular parameter values given in the following basic protocols, e.g. the electric power and process gas flow, are typical values. Whenever parameter values were changed in comparison to these typical values, this will be indicated in the subsequent working examples. The same applies to the type and composition of the process gas.
Cyclic olefin copolymer (COC) tubes of the shape and size commonly used as evacuated blood collection tubes (“COC tubes”) were injection molded from Topas® 8007-04 cyclic olefin copolymer (COC) resin, available from Hoechst AG, Frankfurt am Main, Germany, having these dimensions: 75 mm length, 13 mm outer diameter, and 0.85 mm wall thickness, each having a volume of about 7.25 cm3 and a closed, rounded end.
Polyethylene terephthalate (PET) tubes of the type commonly used as evacuated blood collection tubes (“PET tubes”) were injection molded in the same mold used for the Protocol for Forming COC Tube, having these dimensions: 75 mm length, 13 mm outer diameter, and 0.85 mm wall thickness, each having a volume of about 7.25 cm3 and a closed, rounded end.
Protocol for Coating Tube Interior with SiOx
The apparatus as shown in
The electrode 160 was made from copper with a Delrin® shield. The Delrin® shield was conformal around the outside of the copper electrode 160. The electrode 160 measured approximately 3 inches (76 mm) high (inside) and was approximately 0.75 inches (19 mm) wide.
The tube used as the vessel 80 was inserted into the vessel holder 50 base sealing with Viton® O-rings 490, 504 (Viton® is a trademark of DuPont Performance Elastomers LLC, Wilmington Del., USA) around the exterior of the tube. The tube 80 was carefully moved into the sealing position over the extended (stationary) ⅛-inch (3-mm) diameter brass probe or counter electrode 108 and pushed against a copper plasma screen.
The copper plasma screen was a perforated copper foil material (K&S Engineering, Chicago III., USA, Part #LXMUW5 copper mesh) cut to fit the outside diameter of the tube, and was held in place by a radially extending abutment surface that acted as a stop for the tube insertion. Two pieces of the copper mesh were fit snugly around the brass probe or counter electrode 108, insuring good electrical contact.
The brass probe or counter electrode 108 extended approximately 70 mm into the interior of the tube and had an array of #80 wire (diameter=0.0135 inch or 0.343 mm). The brass probe or counter electrode 108 extended through a Swagelok® fitting (available from Swagelok Co., Solon Ohio, USA) located at the bottom of the vessel holder 50, extending through the vessel holder 50 base structure. The brass probe or counter electrode 108 was grounded to the casing of the RF matching network.
The gas delivery port 110 was 12 holes in the probe or counter electrode 108 along the length of the tube (three on each of four sides oriented 90 degrees from each other) and two holes in the aluminum cap that plugged the end of the gas delivery port 110. The gas delivery port 110 was connected to a stainless steel assembly comprised of Swagelok® fittings incorporating a manual ball valve for venting, a thermocouple pressure gauge and a bypass valve connected to the vacuum pumping line. In addition, the gas system was connected to the gas delivery port 110 allowing the process gases, oxygen and hexamethyldisiloxane (HMDSO) to be flowed through the gas delivery port 110 (under process pressures) into the interior of the tube.
The gas system was comprised of a Aalborg® GFC17 mass flow meter (Part # EW-32661-34, Cole-Parmer Instrument Co., Barrington III. USA) for controllably flowing oxygen at 90 sccm (or at the specific flow reported for a particular example) into the process and a polyether ether ketone (“PEEK”) capillary (outside diameter, “OD” 1/16-inch (1.5-mm.), inside diameter, “ID” 0.004 inch (0.1 mm)) of length 49.5 inches (1.26 m). The PEEK capillary end was inserted into liquid hexamethyldisiloxane (“HMDSO,” Alfa Aesar® Part Number L16970, NMR Grade, available from Johnson Matthey PLC, London). The liquid HMDSO was pulled through the capillary due to the lower pressure in the tube during processing. The HMDSO was then vaporized into a vapor at the exit of the capillary as it entered the low pressure region.
To ensure no condensation of the liquid HMDSO past this point, the gas stream (including the oxygen) was diverted to the pumping line when it was not flowing into the interior of the tube for processing via a Swagelok® 3-way valve. Once the tube was installed, the vacuum pump valve was opened to the vessel holder 50 and the interior of the tube.
An Alcatel rotary vane vacuum pump and blower comprised the vacuum pump system. The pumping system allowed the interior of the tube to be reduced to pressure(s) of less than 200 mTorr while the process gases were flowing at the indicated rates.
Once the base vacuum level was achieved, the vessel holder 50 assembly was moved into the electrode 160 assembly. The gas stream (oxygen and HMDSO vapor) was flowed into the brass gas delivery port 110 (by adjusting the 3-way valve from the pumping line to the gas delivery port 110). Pressure inside the tube was approximately 300 mTorr as measured by a capacitance manometer (MKS) installed on the pumping line near the valve that controlled the vacuum. In addition to the tube pressure, the pressure inside the gas delivery port 110 and gas system was also measured with the thermocouple vacuum gauge that was connected to the gas system. This pressure was typically less than 8 Torr.
Once the gas was flowing to the interior of the tube, the RF power supply was turned on to its fixed power level. A ENI ACG-6 600 Watt RF power supply was used (at 13.56 MHz) at a fixed power level of approximately 50 Watts. The output power was calibrated in this and all following Protocols and Examples using a Bird Corporation Model 43 RF Watt meter connected to the RF output of the power supply during operation of the coating apparatus. The following relationship was found between the dial setting on the power supply and the output power: RF Power Out=55.times.Dial Setting. In the priority applications to the present application, a factor 100 was used, which was incorrect. The RF power supply was connected to a COMDEL CPMX1000 auto match which matched the complex impedance of the plasma (to be created in the tube) to the 50 ohm output impedance of the ENI ACG-6 RF power supply. The forward power was 50 Watts (or the specific amount reported for a particular example) and the reflected power was 0 Watts so that the applied power was delivered to the interior of the tube. The RF power supply was controlled by a laboratory timer and the power on time set to 5 seconds (or the specific time period reported for a particular example). Upon initiation of the RF power, a uniform plasma was established inside the interior of the tube. The plasma was maintained for the entire 5 seconds until the RF power was terminated by the timer. The plasma produced a silicon oxide coating of approximately 20 nm thickness (or the specific thickness reported in a particular example) on the interior of the tube surface.
After coating, the gas flow was diverted back to the vacuum line and the vacuum valve was closed. The vent valve was then opened, returning the interior of the tube to atmospheric pressure (approximately 760 Torr). The tube was then carefully removed from the vessel holder 50 assembly (after moving the vessel holder 50 assembly out of the electrode 160 assembly).
Syringe barrels (“COC syringe barrels”), CV Holdings Part 11447, each having a 2.8 mL overall volume (excluding the Luer fitting) and a nominal 1 mL delivery volume or plunger displacement, Luer adapter type, were injection molded from Topas® 8007-04 cyclic olefin copolymer (COC) resin, available from Hoechst AG, Frankfurt am Main, Germany, having these dimensions: about 51 mm overall length, 8.6 mm inner syringe barrel diameter and 1.27 mm wall thickness at the cylindrical portion, with an integral 9.5 millimeter length needle capillary Luer adapter molded on one end and two finger flanges molded near the other end.
Protocol for Coating COC Syringe Barrel Interior with SiOx
An injection molded COC syringe barrel was interior coated with SiOx. The apparatus as shown in
The vessel holder 50 was made from Delrin® with an outside diameter of 1.75 inches (44 mm) and a height of 1.75 inches (44 mm). The vessel holder 50 was housed in a Delrin® structure that allowed the device to move in and out of the electrode 160.
The electrode 160 was made from copper with a Delrin® shield. The Delrin® shield was conformal around the outside of the copper electrode 160. The electrode 160 measured approximately 3 inches (76 mm) high (inside) and was approximately 0.75 inches (19 mm) wide. The COC syringe barrel was inserted into the vessel holder 50, base sealing with an Viton® O-rings.
The COC syringe barrel was carefully moved into the sealing position over the extended (stationary) ⅛-inch (3-mm.) diameter brass probe or counter electrode 108 and pushed against a copper plasma screen. The copper plasma screen was a perforated copper foil material (K&S Engineering Part #LXMUW5 Copper mesh) cut to fit the outside diameter of the COC syringe barrel and was held in place by a abutment surface that acted as a stop for the COC syringe barrel insertion. Two pieces of the copper mesh were fit snugly around the brass probe or counter electrode 108 insuring good electrical contact.
The probe or counter electrode 108 extended approximately 20 mm into the interior of the COC syringe barrel and was open at its end. The brass probe or counter electrode 108 extended through a Swagelok® fitting located at the bottom of the vessel holder 50, extending through the vessel holder 50 base structure. The brass probe or counter electrode 108 was grounded to the casing of the RF matching network.
The gas delivery port 110 was connected to a stainless steel assembly comprised of Swagelok® fittings incorporating a manual ball valve for venting, a thermocouple pressure gauge and a bypass valve connected to the vacuum pumping line. In addition, the gas system was connected to the gas delivery port 110 allowing the process gases, oxygen and hexamethyldisiloxane (HMDSO) to be flowed through the gas delivery port 110 (under process pressures) into the interior of the COC syringe barrel.
The gas system was comprised of a Aalborg® GFC17 mass flow meter (Cole Parmer Part # EW-32661-34) for controllably flowing oxygen at 90 sccm (or at the specific flow reported for a particular example) into the process and a PEEK capillary (OD 1/16-inch (3-mm) ID 0.004 inches (0.1 mm)) of length 49.5 inches (1.26 m). The PEEK capillary end was inserted into liquid hexamethyldisiloxane (Alfa Aesar® Part Number L16970, NMR Grade). The liquid HMDSO was pulled through the capillary due to the lower pressure in the COC syringe barrel during processing. The HMDSO was then vaporized into a vapor at the exit of the capillary as it entered the low pressure region.
To ensure no condensation of the liquid HMDSO past this point, the gas stream (including the oxygen) was diverted to the pumping line when it was not flowing into the interior of the COC syringe barrel for processing via a Swagelok® 3-way valve.
Once the COC syringe barrel was installed, the vacuum pump valve was opened to the vessel holder 50 and the interior of the COC syringe barrel. An Alcatel rotary vane vacuum pump and blower comprised the vacuum pump system. The pumping system allowed the interior of the COC syringe barrel to be reduced to pressure(s) of less than 150 mTorr while the process gases were flowing at the indicated rates. A lower pumping pressure was achievable with the COC syringe barrel, as opposed to the tube, because the COC syringe barrel has a much smaller internal volume.
After the base vacuum level was achieved, the vessel holder 50 assembly was moved into the electrode 160 assembly. The gas stream (oxygen and HMDSO vapor) was flowed into the brass gas delivery port 110 (by adjusting the 3-way valve from the pumping line to the gas delivery port 110). The pressure inside the COC syringe barrel was approximately 200 mTorr as measured by a capacitance manometer (MKS) installed on the pumping line near the valve that controlled the vacuum. In addition to the COC syringe barrel pressure, the pressure inside the gas delivery port 110 and gas system was also measured with the thermocouple vacuum gauge that was connected to the gas system. This pressure was typically less than 8 Torr.
When the gas was flowing to the interior of the COC syringe barrel, the RF power supply was turned on to its fixed power level. A ENI ACG-6 600 Watt RF power supply was used (at 13.56 MHz) at a fixed power level of approximately 30 Watts. The RF power supply was connected to a COMDEL CPMX1000 auto match that matched the complex impedance of the plasma (to be created in the COC syringe barrel) to the 50 ohm output impedance of the ENI ACG-6 RF power supply. The forward power was 30 Watts (or whatever value is reported in a working example) and the reflected power was 0 Watts so that the power was delivered to the interior of the COC syringe barrel. The RF power supply was controlled by a laboratory timer and the power on time set to 5 seconds (or the specific time period reported for a particular example).
Upon initiation of the RF power, a uniform plasma was established inside the interior of the COC syringe barrel. The plasma was maintained for the entire 5 seconds (or other coating time indicated in a specific example) until the RF power was terminated by the timer. The plasma produced a silicon oxide coating of approximately 20 nm thickness (or the thickness reported in a specific example) on the interior of the COC syringe barrel surface.
After coating, the gas flow was diverted back to the vacuum line and the vacuum valve was closed. The vent valve was then opened, returning the interior of the COC syringe barrel to atmospheric pressure (approximately 760 Torr). The COC syringe barrel was then carefully removed from the vessel holder 50 assembly (after moving the vessel holder 50 assembly out of the electrode 160 assembly).
Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity Layer
COC syringe barrels as previously identified were interior coated with a lubricity layer. The apparatus as shown in
The vessel holder 50 was made from Delrin® with an outside diameter of 1.75 inches (44 mm) and a height of 1.75 inches (44 mm). The vessel holder 50 was housed in a Delrin® structure that allowed the device to move in and out of the electrode 160.
The electrode 160 was made from copper with a Delrin® shield. The Delrin® shield was conformal around the outside of the copper electrode 160. The electrode 160 measured approximately 3 inches (76 mm) high (inside) and was approximately 0.75 inches (19 mm) wide. The COC syringe barrel was inserted into the vessel holder 50, base sealing with Viton® O-rings around the bottom of the finger flanges and lip of the COC syringe barrel.
The COC syringe barrel was carefully moved into the sealing position over the extended (stationary) ⅛-inch (3-mm.) diameter brass probe or counter electrode 108 and pushed against a copper plasma screen. The copper plasma screen was a perforated copper foil material (K&S Engineering Part #LXMUW5 Copper mesh) cut to fit the outside diameter of the COC syringe barrel and was held in place by a abutment surface 494 that acted as a stop for the COC syringe barrel insertion. Two pieces of the copper mesh were fit snugly around the brass probe or counter electrode 108 insuring good electrical contact.
The probe or counter electrode 108 extended approximately 20 mm (unless otherwise indicated) into the interior of the COC syringe barrel and was open at its end. The brass probe or counter electrode 108 extended through a Swagelok® fitting located at the bottom of the vessel holder 50, extending through the vessel holder 50 base structure. The brass probe or counter electrode 108 was grounded to the casing of the RF matching network.
The gas delivery port 110 was connected to a stainless steel assembly comprised of Swagelok® fittings incorporating a manual ball valve for venting, a thermocouple pressure gauge and a bypass valve connected to the vacuum pumping line. In addition, the gas system was connected to the gas delivery port 110 allowing the process gas, octamethylcyclotetrasiloxane (OMCTS) (or the specific process gas reported for a particular example) to be flowed through the gas delivery port 110 (under process pressures) into the interior of the COC syringe barrel.
The gas system was comprised of a commercially available Horiba VC1310/SEF8240 OMCTS10SC 4CR heated mass flow vaporization system that heated the OMCTS to about 100.degree. C. The Horiba system was connected to liquid octamethylcyclotetrasiloxane (Alfa Aesar® Part Number A12540, 98%) through a 1/8-inch (3-mm) outside diameter PFA tube with an inside diameter of 1/16 in (1.5 mm). The OMCTS flow rate was set to 1.25 sccm (or the specific organosilicon precursor flow reported for a particular example). To ensure no condensation of the vaporized OMCTS flow past this point, the gas stream was diverted to the pumping line when it was not flowing into the interior of the COC syringe barrel for processing via a Swagelok® 3-way valve.
Once the COC syringe barrel was installed, the vacuum pump valve was opened to the vessel holder 50 and the interior of the COC syringe barrel. An Alcatel rotary vane vacuum pump and blower comprised the vacuum pump system. The pumping system allowed the interior of the COC syringe barrel to be reduced to pressure(s) of less than 100 mTorr while the process gases were flowing at the indicated rates. A lower pressure could be obtained in this instance, compared to the tube and previous COC syringe barrel examples, because the overall process gas flow rate is lower in this instance.
Once the base vacuum level was achieved, the vessel holder 50 assembly was moved into the electrode 160 assembly. The gas stream (OMCTS vapor) was flowed into the brass gas delivery port 110 (by adjusting the 3-way valve from the pumping line to the gas delivery port 110). Pressure inside the COC syringe barrel was approximately 140 mTorr as measured by a capacitance manometer (MKS) installed on the pumping line near the valve that controlled the vacuum. In addition to the COC syringe barrel pressure, the pressure inside the gas delivery port 110 and gas system was also measured with the thermocouple vacuum gauge that was connected to the gas system. This pressure was typically less than 6 Torr.
Once the gas was flowing to the interior of the COC syringe barrel, the RF power supply was turned on to its fixed power level. A ENI ACG-6 600 Watt RF power supply was used (at 13.56 MHz) at a fixed power level of approximately 7.5 Watts (or other power level indicated in a specific example). The RF power supply was connected to a COMDEL CPMX1000 auto match which matched the complex impedance of the plasma (to be created in the COC syringe barrel) to the 50 ohm output impedance of the ENI ACG-6 RF power supply. The forward power was 7.5 Watts and the reflected power was 0 Watts so that 7.5 Watts of power (or a different power level delivered in a given example) was delivered to the interior of the COC syringe barrel. The RF power supply was controlled by a laboratory timer and the power on time set to 10 seconds (or a different time stated in a given example).
Upon initiation of the RF power, a uniform plasma was established inside the interior of the COC syringe barrel. The plasma was maintained for the entire coating time, until the RF power was terminated by the timer. The plasma produced a lubricity layer on the interior of the COC syringe barrel surface.
After coating, the gas flow was diverted back to the vacuum line and the vacuum valve was closed. The vent valve was then opened, returning the interior of the COC syringe barrel to atmospheric pressure (approximately 760 Torr). The COC syringe barrel was then carefully removed from the vessel holder 50 assembly (after moving the vessel holder 50 assembly out of the electrode 160 assembly).
Protocol for Coating COC Syringe Barrel Interior with HMDSO Coating
The Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer was also used for applying an HMDSO coating, except substituting HMDSO for OMCTS.
In the following test, hexamethyldisiloxane (HMDSO) was used as the organosilicon (“O—Si”) feed to PECVD apparatus of
Referring to Table 1, the uncoated COC tube had an OTR of 0.215 cc/tube/day. Tubes A and B subjected to PECVD for 14 seconds had an average OTR of 0.0235 cc/tube/day. These results show that the SiOx coating provided an oxygen transmission BIF over the uncoated tube of 9.1. In other words, the SiOx barrier layer reduced the oxygen transmission through the tube to less than one ninth its value without the coating.
Tube C subjected to PECVD for 7 seconds had an OTR of 0.026. This result shows that the SiOx coating provided an OTR BIF over the uncoated tube of 8.3. In other words, the SiOx barrier layer applied in 7 seconds reduced the oxygen transmission through the tube to less than one eighth of its value without the coating.
The relative WVTRs of the same barrier layers on COC tubes were also measured. The uncoated COC tube had a WVTR of 0.27 mg/tube/day. Tubes A and B subjected to PECVD for 14 seconds had an average WVTR of 0.10 mg/tube/day or less. Tube C subjected to PECVD for 7 seconds had a WVTR of 0.10 mg/tube/day. This result shows that the SiOx coating provided a water vapor transmission barrier improvement factor (WVTR BIF) over the uncoated tube of about 2.7. This was a surprising result, since the uncoated COC tube already has a very low WVTR.
A series of PET tubes, made according to the Protocol for Forming PET Tube, were coated with SiOx according to the Protocol for Coating Tube Interior with SiOx under the conditions reported in Table 2. Controls were made according to the Protocol for Forming PET Tube, but left uncoated. OTR and WVTR samples of the tubes were prepared by epoxy-sealing the open end of each tube to an aluminum adaptor.
In a separate test, using the same type of coated PET tubes, mechanical scratches of various lengths were induced with a steel needle through the interior coating, and the OTR BIF was tested. Controls were either left uncoated or were the same type of coated tube without an induced scratch. The OTR BIF, while diminished, was still improved over uncoated tubes (Table 3).
Tubes were tested for OTR as follows. Each sample/adaptor assembly was fitted onto a MOCON® Oxtran 2/21 Oxygen Permeability Instrument. Samples were allowed to equilibrate to transmission rate steady state (1-3 days) under the following test conditions:
The OTR is reported as average of two determinations in Table 2.
Tubes were tested for WVTR as follows. The sample/adaptor assembly was fitted onto a MOCON® Permatran-W 3/31 Water Vapor Permeability Instrument. Samples were allowed to equilibrate to transmission rate steady state (1-3 days) under the following test conditions:
The WVTR is reported as average of two determinations in Table 2.
A series of syringe barrels were made according to the Protocol for Forming COC Syringe barrel. The syringe barrels were either barrier coated with SiOx or not under the conditions reported in the Protocol for Coating COC Syringe barrel Interior with SiOx modified as indicated in Table 4.
OTR and WVTR samples of the syringe barrels were prepared by epoxy-sealing the open end of each syringe barrel to an aluminum adaptor. Additionally, the syringe barrel capillary ends were sealed with epoxy. The syringe-adapter assemblies were tested for OTR or WVTR in the same manner as the PET tube samples, again using a MOCON® Oxtran 2/21 Oxygen Permeability Instrument and a MOCON® Permatran-W 3/31 Water Vapor Permeability Instrument. The results are reported in Table 4.
PET tubes made according to the Protocol for Forming PET Tube and coated according to the Protocol for Coating Tube Interior with SiOx were cut in half to expose the inner tube surface, which was then analyzed using X-ray photoelectron spectroscopy (XPS).
The XPS data was quantified using relative sensitivity factors and a model which assumes a homogeneous layer. The analysis volume is the product of the analysis area (spot size or aperture size) and the depth of information. Photoelectrons are generated within the X-ray penetration depth (typically many microns), but only the photoelectrons within the top three photoelectron escape depths are detected. Escape depths are on the order of 15-35.ANG., which leads to an analysis depth of .about.50-100.ANG. Typically, 95% of the signal originates from within this depth.
Table 6 provides the atomic ratios of the elements detected. The analytical parameters used in for XPS are as follows:
XPS does not detect hydrogen or helium. Values given are normalized to Si=1 for the experimental number (last row) using the elements detected, and to O=1 for the uncoated polyethylene terephthalate calculation and example. Detection limits are approximately 0.05 to 1.0 atomic percent. Values given are alternatively normalized to 100% Si+O+C atoms.
The Inventive Example has an Si/O ratio of 2.4 indicating an SiOx composition, with some residual carbon from incomplete oxidation of the coating. This analysis demonstrates the composition of an SiOx barrier layer applied to a polyethylene terephthalate tube according to the present invention.
Table 5 shows the thickness of the SiOx samples, determined using TEM according to the following method. Samples were prepared for Focused Ion Beam (FIB) cross-sectioning by coating the samples with a sputtered layer of platinum (50-100 nm thick) using a K575X Emitech coating system. The coated samples were placed in an FEI FIB200 FIB system. An additional layer of platinum was FIB-deposited by injection of an organometallic gas while rastering the 30 kV gallium ion beam over the area of interest. The area of interest for each sample was chosen to be a location half way down the length of the tube. Thin cross sections measuring approximately 15.mu.m (“micrometers”) long, 2.mu.m wide and 15.mu.m deep were extracted from the die surface using a proprietary in-situ FIB lift-out technique. The cross sections were attached to a 200 mesh copper TEM grid using FIB-deposited platinum. One or two windows in each section, measuring about 8.mu.m wide, were thinned to electron transparency using the gallium ion beam of the FEI FIB.
The sample grids were transferred to a Hitachi HF2000 transmission electron microscope. Transmitted electron images were acquired at appropriate magnifications. The relevant instrument settings used during image acquisition are given below.
COC syringe barrels made according to the Protocol for Forming COC Syringe barrel were treated using the Protocol for Coating COC Syringe Barrel Interior with SiOx, with the following variations. Three different modes of plasma generation were tested for coating syringe barrels such as 250 with SiOx films. In Mode 1, hollow cathode plasma ignition was generated in the gas inlet 310, restricted area 292 and processing vessel lumen 304, and ordinary or non-hollow-cathode plasma was generated in the remainder of the vessel lumen 300.
In Mode 2, hollow cathode plasma ignition was generated in the restricted area 292 and processing vessel lumen 304, and ordinary or non-hollow-cathode plasma was generated in the remainder of the vessel lumen 300 and gas inlet 310.
In Mode 3, ordinary or non-hollow-cathode plasma was generated in the entire vessel lumen 300 and gas inlet 310. This was accomplished by ramping up power to quench any hollow cathode ignition. Table 7 shows the conditions used to achieve these modes.
The syringe barrels 250 were then exposed to a ruthenium oxide staining technique. The stain was made from sodium hypochlorite bleach and Ru(III) chloride hydrate. 0.2 g of Ru(III) chloride hydrate was put into a vial. 10 ml bleach were added and mixed thoroughly until the Ru(III) chloride hydrate dissolved.
Each syringe barrel was sealed with a plastic Luer seal and 3 drops of the staining mixture were added to each syringe barrel. The syringe barrels were then sealed with aluminum tape and allowed to sit for 30-40 minutes. In each set of syringe barrels tested, at least one uncoated syringe barrel was stained. The syringe barrels were stored with the restricted area 292 facing up.
Based on the staining, the following conclusions were drawn:
1. The stain started to attack the uncoated (or poorly coated) areas within 0.25 hours of exposure.
2. Ignition in the restricted area 292 resulted in SiOx coating of the restricted area 292.
3. The best syringe barrel was produced by the test with no hollow cathode plasma ignition in either the gas inlet 310 or the restricted area 292. Only the restricted opening 294 was stained, most likely due to leaking of the stain.
4. Staining is a good qualitative tool to guide uniformity work.
Based on all of the above, we concluded:
1. Under the conditions of the test, hollow cathode plasma in either the gas inlet 310 or the restricted area 292 led to poor uniformity of the coating.
2. The best uniformity was achieved with no hollow cathode plasma in either the gas inlet 310 or the restricted area 292.
The following materials were used in this test:
The following procedure was used in this test.
The jig was installed on the Dillon Test Stand. The platform probe movement was adjusted to 6 in/min (2.5 mm/sec) and upper and lower stop locations were set. The stop locations were verified using an empty syringe and barrel. The commercial saline-filled syringes were labeled, the plungers were removed, and the saline solution was drained via the open ends of the syringe barrels for re-use. Extra plungers were obtained in the same manner for use with the COC and glass barrels.
Syringe plungers were inserted into the COC syringe barrels so that the second horizontal molding point of each plunger was even with the syringe barrel lip (about 10 mm from the tip end). Using another syringe and needle assembly, the test syringes were filled via the capillary end with 2-3 milliliters of saline solution, with the capillary end uppermost. The sides of the syringe were tapped to remove any large air bubbles at the plunger/fluid interface and along the walls, and any air bubbles were carefully pushed out of the syringe while maintaining the plunger in its vertical orientation.
Each filled syringe barrel/plunger assembly was installed into the syringe jig. The test was initiated by pressing the down switch on the test stand to advance the moving metal hammer toward the plunger. When the moving metal hammer was within 5 mm of contacting the top of the plunger, the data button on the Dillon module was repeatedly tapped to record the force at the time of each data button depression, from before initial contact with the syringe plunger until the plunger was stopped by contact with the front wall of the syringe barrel.
All benchmark and coated syringe barrels were run with five replicates (using a new plunger and barrel for each replicate).
COC syringe barrels made according to the Protocol for Forming COC Syringe barrel were coated with an OMCTS lubricity layer according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer, assembled and filled with saline, and tested as described above in this Example for lubricity layers. The polypropylene chamber used per the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer allowed the OMCTS vapor (and oxygen, if added—see Table 8) to flow through the syringe barrel and through the syringe capillary into the polypropylene chamber (although a lubricity layer is not needed in the capillary section of the syringe in this instance). Several different coating conditions were tested, as shown in previously mentioned Table 8. All of the depositions were completed on COC syringe barrels from the same production batch.
The coated samples were then tested using the plunger sliding force test per the protocol of this Example, yielding the results in Table 8, in English and metric force units. The data shows clearly that low power and no oxygen provided the lowest plunger sliding force for COC and coated COC syringes. Note that when oxygen was added at lower power (6 W) (the lower power being a favorable condition) the plunger sliding force increased from 1.09 lb., 0.49 Kg (at Power=11 W) to 2.27 lb., 1.03 Kg. This indicates that the addition of oxygen may not be desirable to achieve the lowest possible plunger sliding force.
Note also that the best plunger sliding force (Power=11 W, plunger sliding force=1.09 lb., 0.49 Kg) was very near the current industry standard of silicone coated glass (plunger sliding force=0.58 lb., 0.26 Kg), while avoiding the problems of a glass syringe such as breakability and a more expensive manufacturing process. With additional optimization, values equal to or better than the current glass with silicone performance are expected to be achieved.
The samples were created by coating COC syringe barrels according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer. An alternative embodiment of the technology herein, would apply the lubricity layer over another thin film coating, such as SiOx, for example applied according to the Protocol for Coating COC Syringe barrel Interior with SiOx.
The force required to expel a 0.9 percent saline payload from a syringe through a capillary opening using a plastic plunger was determined for inner wall-coated syringes.
Three types of COC syringe barrels made according to the Protocol for Forming COC Syringe barrel were tested: one type having no internal coating [Uncoated Control], another type with a hexamethyldisiloxane (HMDSO)-based plasma coated internal wall coating [HMDSO Control] according to the Protocol for Coating COC Syringe Barrel Interior with HMDSO Coating, and a third type with an octamethylcyclotetrasiloxane [OMCTS-Inventive Example]-based plasma coated internal wall coating applied according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer. Fresh plastic plungers with elastomeric tips taken from BD Product Becton-Dickinson Product No. 306507 were used for all examples. Saline from Product No. 306507 was also used.
The plasma coating method and apparatus for coating the syringe barrel inner walls is described in other experimental sections of this application. The specific coating parameters for the HMDSO-based and OMCTS-based coatings are listed in the Protocol for Coating COC Syringe Barrel Interior with HMDSO Coating, the Protocol for Coating COC Syringe barrel Interior with OMCTS Lubricity layer, and Table 9.
The plunger is inserted into the syringe barrel to about 10 millimeters, followed by vertical filling of the experimental syringe through the open syringe capillary with a separate saline-filled syringe/needle system. When the experimental syringe has been filled into the capillary opening, the syringe is tapped to permit any air bubbles adhering to the inner walls to release and rise through the capillary opening.
The filled experimental syringe barrel/plunger assembly is placed vertically into a home-made hollow metal jig, the syringe assembly being supported on the jig at the finger flanges. The jig has a drain tube at the base and is mounted on Dillon Test Stand with Advanced Force Gauge (Model AFG-50N). The test stand has a metal hammer, moving vertically downward at a rate of six inches (152 millimeters) per minute. The metal hammer contacts the extended plunger expelling the saline solution through the capillary. Once the plunger has contacted the syringe barrel/capillary interface the experiment is stopped.
During downward movement of the metal hammer/extended plunger, resistance force imparted on the hammer as measured on the Force Gauge is recorded on an electronic spreadsheet. From the spreadsheet data, the maximum force for each experiment is identified.
Table 9 lists for each Example the Maximum Force average from replicate coated COC syringe barrels and the Normalized Maximum Force as determined by division of the coated syringe barrel Maximum Force average by the uncoated Maximum Force average.
The data indicates all OMCTS-based inner wall plasma coated COC syringe barrels (Inventive Examples C, E, F, G, H) demonstrate much lower plunger sliding force than uncoated COC syringe barrels (uncoated Control Examples A & D) and surprisingly, also much lower plunger sliding force than HMDSO-based inner wall plasma coated COC syringe barrels (HMDSO control Example B). More surprising, an OMCTS-based coating over a silicon oxide (SiOx) gas barrier layer maintains excellent low plunger sliding force (Inventive Example F). The best plunger sliding force was Example C (Power=8, plunger sliding force=1.1 lb., 0.5 Kg). It was very near the current industry standard of silicone coated glass (plunger sliding force=0.58 lb., 0.26 Kg.), while avoiding the problems of a glass syringe such as breakability and a more expensive manufacturing process. With additional optimization, values equal to or better than the current glass with silicone performance are expected to be achieved.
Fabrication of COC Syringe Barrel with Exterior Coating
A COC syringe barrel formed according to the Protocol for Forming COC Syringe barrel is sealed at both ends with disposable closures. The capped COC syringe barrel is passed through a bath of Daran® 8100 Saran Latex (Owensboro Specialty Plastics). This latex contains five percent isopropyl alcohol to reduce the surface tension of the composition to 32 dynes/cm). The latex composition completely wets the exterior of the COC syringe barrel. After draining for 30 seconds, the coated COC syringe barrel is exposed to a heating schedule comprising 275.degree. F. (135.degree. C.) for 25 seconds (latex coalescence) and 122.degree. F. (50.degree. C.) for four hours (finish cure) in respective forced air ovens. The resulting PVdC film is 1/10 mil (2.5 microns) thick. The COC syringe barrel and PVdC-COC laminate COC syringe barrel are measured for OTR and WVTR using a MOCON brand Oxtran 2/21 Oxygen Permeability Instrument and Permatran-W 3/31 Water Vapor Permeability Instrument, respectively.
Predicted OTR and WVTR values are listed in Table 10, which shows the expected Barrier Improvement Factor (BIF) for the laminate would be 4.3 (OTR-BIF) and 3.0 (WVTR-BIF), respectively.
COC syringe barrel samples made according to the Protocol for Forming COC Syringe barrel, coated with OMCTS (according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer) or coated with HMDSO according to the Protocol for Coating COC Syringe Barrel Interior with HMDSO Coating were provided. The atomic compositions of the coatings derived from OMCTS or HMDSO were characterized using X-Ray Photoelectron Spectroscopy (XPS).
XPS data is quantified using relative sensitivity factors and a model that assumes a homogeneous layer. The analysis volume is the product of the analysis area (spot size or aperture size) and the depth of information. Photoelectrons are generated within the X-ray penetration depth (typically many microns), but only the photoelectrons within the top three photoelectron escape depths are detected. Escape depths are on the order of 15-35.ANG., which leads to an analysis depth of −50-100.ANG. Typically, 95% of the signal originates from within this depth.
The following analytical parameters were used:
Table 11 provides the atomic concentrations of the elements detected. XPS does not detect hydrogen or helium. Values given are normalized to 100 percent using the elements detected. Detection limits are approximately 0.05 to 1.0 atomic percent.
From the coating composition results and calculated starting monomer precursor elemental percent in Table 11, while the carbon atom percent of the HMDSO-based coating is decreased relative to starting HMDSO monomer carbon atom percent (54.1% down to 44.4%), surprisingly the OMCTS-based coating carbon atom percent is increased relative to the OMCTS monomer carbon atom percent (34.8% up to 48.4%), an increase of 39 atomic %, calculated as follows:
100%[(48.4/34.8)−1]=39 at. %.
Also, while the silicon atom percent of the HMDSO-based coating is almost unchanged relative to starting HMDSO monomer silicon atom percent (21.8% to 22.2%), surprisingly the OMCTS-based coating silicon atom percent is significantly decreased relative to the OMCTS monomer silicon atom percent (42.0% down to 23.6%), a decrease of 44 atomic %. With both the carbon and silicon changes, the OMCTS monomer to coating behavior does not trend with that observed in common precursor monomers (e.g. HMDSO). See, e.g., Hans J. Griesser, Ronald C. Chatelier, Chris Martin, Zoran R. Vasic, Thomas R. Gengenbach, George Jessup J. Biomed. Mater. Res. (Appl. Biomater.) 53: 235-243, 2000.
Volatile Components from Plasma Coatings (“Outgassing”)
COC syringe barrel samples made according to the Protocol for Forming COC Syringe barrel, coated with OMCTS (according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer) or with HMDSO (according to the Protocol for Coating COC Syringe Barrel Interior with HMDSO Coating) were provided. Outgassing gas chromatography/mass spectroscopy (GC/MS) analysis was used to measure the volatile components released from the OMCTS or HMDSO coatings.
The syringe barrel samples (four COC syringe barrels cut in half lengthwise) were placed in one of the 1½″ (37 mm) diameter chambers of a dynamic headspace sampling system (CDS 8400 auto-sampler). Prior to sample analysis, a system blank was analyzed. The sample was analyzed on an Agilent 7890A Gas Chromatograph/Agilent 5975 Mass Spectrometer, using the following parameters, producing the data set out in Table 12:
GC Column: 30 m.times.0.25 mm DB-5MS (J&W Scientific), 0.25.mu.m film thickness [0872] Flow rate: 1.0 ml/min, constant flow mode [0873] Detector: Mass Selective Detector (MSD) [0874] Injection Mode: Split injection (10:1 split ratio) [0875] Outgassing Conditions: 1½″ (37 mm) Chamber, purge for three hour at 85.degree. C., flow 60 ml/min [0876] Oven temperature: 40.degree. C. (5 min.) to 300.degree. C. @10.degree. C./min.; hold for 5 min. at 300.degree. C.
The outgassing results from Table 12 clearly indicated a compositional differentiation between the HMDSO-based and OMCTS-based lubricity layers tested. HMDSO-based compositions outgassed trimethylsilanol [(Me)3SiOH] but outgassed no measured higher oligomers containing repeating -(Me)2SiO— moieties, while OMCTS-based compositions outgassed no measured trimethylsilanol [(Me)3SiOH] but outgassed higher oligomers containing repeating -(Me)2SiO— moieties. It is contemplated that this test can be useful for differentiating HMDSO-based coatings from OMCTS-based coatings.
Without limiting the invention according to the scope or accuracy of the following theory, it is contemplated that this result can be explained by considering the cyclic structure of OMCTS, with only two methyl groups bonded to each silicon atom, versus the acyclic structure of HMDSO, in which each silicon atom is bonded to three methyl groups. OMCTS is contemplated to react by ring opening to form a diradical having repeating -(Me)2SiO— moieties which are already oligomers, and can condense to form higher oligomers. HMDSO, on the other hand, is contemplated to react by cleaving at one O—Si bond, leaving one fragment containing a single O—Si bond that recondenses as (Me)3SiOH and the other fragment containing no O—Si bond that recondenses as [(Me)3Si]2.
The cyclic nature of OMCTS is believed to result in ring opening and condensation of these ring-opened moieties with outgassing of higher MW oligomers (26 ng/test). In contrast, HMDSO-based coatings are believed not to provide any higher oligomers, based on the relatively low-molecular-weight fragments from HMDSO.
Sapphire witness samples (0.5.times.0.5.times.0.1 cm) were glued to the inner walls of separate PET tubes, made according to the Protocol for Forming PET tubes. The sapphire witness-containing PET tubes were coated with OMCTS or HMDSO (both according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer, deviating all with 2.times. power). The coated sapphire samples were then removed and X-ray reflectivity (XRR) data were acquired on a PANalytical X'Pert diffractometer equipped with a parabolic multilayer incident beam monochromator and a parallel plate diffracted beam collimator. A two layer SiwOxCyHz model was used to determine coating density from the critical angle measurement results. This model is contemplated to offer the best approach to isolate the true SiwOxCyHz coating. The results are shown in Table 13.
From Table 11 showing the results of Example 9, the lower oxygen (28%) and higher carbon (48.4%) composition of OMCTS versus HMDSO would suggest OMCTS should have a lower density, due to both atomic mass considerations and valency (oxygen=2; carbon=4). Surprisingly, the XRR density results indicate the opposite would be observed, that is, the OMCTS density is higher than HMDSO density.
Without limiting the invention according to the scope or accuracy of the following theory, it is contemplated that there is a fundamental difference in reaction mechanism in the formation of the respective HMDSO-based and OMCTS-based coatings. HMDSO fragments can more easily nucleate or react to form dense nanoparticles which then deposit on the surface and react further on the surface, whereas OMCTS is much less likely to form dense gas phase nanoparticles. OMCTS reactive species are much more likely to condense on the surface in a form much more similar to the original OMCTS monomer, resulting in an overall less dense coating.
Samples were provided of COC syringe barrels made according to the Protocol for Forming COC Syringe barrel and respectively coated with SiOx according to the Protocol for Coating COC Syringe Barrel Interior with SiOx or an OMCTS-based lubricity layer according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer. Samples were also provided of PET tubes made according to the Protocol for Forming PET Tube, respectively coated and uncoated with SiOx according to the Protocol for Coating Tube Interior with SiOx and subjected to an accelerated aging test. Transmission electron microscopy (TEM) was used to measure the thickness of the PECVD-applied coatings on the samples. The previously stated TEM procedure of Example 4 was used. The method and apparatus described by the SiOx and lubricity layer protocols used in this example demonstrated uniform coating as shown in Table 14.
COC syringe barrels made according to the Protocol for Forming COC Syringe Barrel were coated with a lubricity layer according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer. The results are provided in Table 15. The results show that the trend of increasing the power level, in the absence of oxygen, from 8 to 14 Watts was to improve the lubricity of the coating. Further experiments with power and flow rates can provide further enhancement of lubricity.
Injection molded cyclic olefin copolymer (COC) plastic syringe barrels are made according to the Protocol for Forming COC Syringe Barrel. Some are uncoated (“control”) and others are PECVD lubricity coated according to the Protocol for Coating COC Syringe Barrel Interior with OMCTS Lubricity layer (“lubricated syringe”). The lubricated syringes and controls are tested to measure the force to initiate movement of the plunger in the barrel (breakout force) and the force to maintain movement of the plunger in the barrel (plunger sliding force) using a Genesis Packaging Automated Syringe Force Tester, Model AST.
The test is a modified version of the ISO 7886-1:1993 test. The following procedure is used for each test. A fresh plastic plunger with elastomeric tip taken from Becton Dickinson Product No. 306507 (obtained as saline prefilled syringes) is removed from the syringe assembly. The elastomeric tip is dried with clean dry compressed air. The elastomeric tip and plastic plunger are then inserted into the COC plastic syringe barrel to be tested with the plunger positioned even with the bottom of the syringe barrel. The filled syringes are then conditioned as necessary to achieve the state to be tested. For example, if the test object is to find out the effect of lubricant coating on the breakout force of syringes after storing the syringes for three months, the syringes are stored for three months to achieve the desired state.
The syringe is installed into a Genesis Packaging Automated Syringe Force Tester. The tester is calibrated at the start of the test per the manufacturer's specification. The tester input variables are Speed=100 mm/minute, Range=10,000. The start button is pushed on the tester. At completion of the test, the breakout force (to initiate movement of the plunger in the barrel) and the plunger sliding force (to maintain movement) are measured, and are found to be substantially lower for the lubricated syringes than for the control syringes.
The first vessel processing system 5501 contains a vessel holder 38 which holds a seated vessel 80. Although
After the first processing at the first processing station (which processing can comprise molding of the vessel, a first inspection of the vessel for defects, coating of the interior surface of the vessel and a second inspection of the vessel for defects, for example of the interior coating), the vessel holder 38 is transported together with the vessel 80 to a second vessel processing station 5502. This transportation is performed by a conveyor arrangement 70, 72, 74. For example, a gripper or several grippers can be provided for gripping the vessel holder 38 and/or the vessel 80 in order to move the vessel/holder combination to the next processing station 5502. Alternatively, only the vessel can be moved without the holder. However, it can be advantageous to move the holder together with the vessel in which case the holder is adapted such that it can be transported by the conveyor arrangement.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.
2, 0.9
Above force measurements are the average of 4 samples.
This is a continuation of U.S. Ser. No. 15/409,165, filed Jan. 18, 2017, now pending, which is a continuation of U.S. Ser. No. 14/305,202, filed Jun. 16, 2014, now U.S. Pat. No. 9,572,526, which is a divisional of U.S. Ser. No. 13/941,154, filed Jul. 12, 2013, now U.S. Pat. No. 8,834,954, which is a continuation of U.S. Ser. No. 13/169,811, filed Jun. 27, 2011, now U.S. Pat. No. 8,512,796, which is a divisional of U.S. Ser. No. 12/779,007, filed May 12, 2010, now U.S. Pat. No. 7,985,188, which claims the priority of U.S. Provisional Ser. Nos. 61/177,984 filed May 13, 2009; 61/222,727, filed Jul. 2, 2009; 61/213,904, filed Jul. 24, 2009; 61/234,505, filed Aug. 17, 2009; 61/261,321, filed Nov. 14, 2009; 61/263,289, filed Nov. 20, 2009; 61/285,813, filed Dec. 11, 2009; 61/298,159, filed Jan. 25, 2010; 61/299,888, filed Jan. 29, 2010; 61/318,197, filed Mar. 26, 2010, and 61/333,625, filed May 11, 2010. These applications are incorporated here by reference in their entirety. Also incorporated by reference in their entirety are the following European patent applications, all filed May 12, 2010: EP10162755.2; EP10162760.2; EP10162756.0; EP10162758.6; EP10162761.0; and EP10162757.8.
| Number | Date | Country | |
|---|---|---|---|
| 61177984 | May 2009 | US | |
| 61222727 | Jul 2009 | US | |
| 61213904 | Jul 2009 | US | |
| 61234505 | Aug 2009 | US | |
| 61261321 | Nov 2009 | US | |
| 61263289 | Nov 2009 | US | |
| 61285813 | Dec 2009 | US | |
| 61298159 | Jan 2010 | US | |
| 61299888 | Jan 2010 | US | |
| 61318197 | Mar 2010 | US | |
| 61333625 | May 2010 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13941154 | Jul 2013 | US |
| Child | 14305202 | US | |
| Parent | 12779007 | May 2010 | US |
| Child | 13169811 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15409165 | Jan 2017 | US |
| Child | 16504636 | US | |
| Parent | 14305202 | Jun 2014 | US |
| Child | 15409165 | US | |
| Parent | 13169811 | Jun 2011 | US |
| Child | 13941154 | US |
