Patent Application
20080243077
1. Field of the Invention
The present invention relates generally to fluid dispensing devices. More particularly, the invention concerns medicament dispensers for dispensing medicinal fluids to ambulatory patients at a precise rate.
2. Discussion of the Prior Art
A number of different types of medicament dispensers for dispensing medicaments to ambulatory patients have been suggested in the past. Many of the devices seek either to improve or to replace the traditional gravity flow and hypodermic syringe methods which have been the standard for delivery of liquid medicaments for many years.
The prior art gravity flow methods typically involve the use of intravenous administration sets and the familiar flexible solution bag suspended above the patient. Such gravimetric methods are cumbersome, imprecise and require bed confinement of the patient. Periodic monitoring of the apparatus by the nurse or doctor is required to detect malfunctions of the infusion apparatus. Accordingly, the prior art devices are not well suited for use in those instances where the patient must be transported to a remote facility for treatment.
As will be fully appreciated from the discussion that follows, the devices of the present invention are particularly useful in combat situations. The ability to quickly and efficaciously treat wounded soldiers, especially in unpredictable or remote care settings, can significantly improve chances for patient survival and recovery. Accurate intravenous (IV) drug and fluid delivery technologies for controlling pain, preventing infection, and providing a means for IV access for rapid infusions during patient transport are needed to treat almost all serious injuries.
It is imperative that battlefield medics begin administering life saving medications as soon as possible after a casualty occurs. The continuous maintenance of these treatments is vital until higher echelon medical facilities can be reached. A compact, portable and ready-to-use infusion device that could be easily brought into the battlefield would allow medics to begin drug infusions immediately. Additionally, it would free them to attend to other seriously wounded patients who may require more hands-on care in the trauma environment following triage. In most serious trauma situations on the battlefield, IV drug delivery is required to treat fluid resuscitation, as well as both pain and infection. Drug infusion devices currently available can impede the timely administration of IV infusions in remote care settings.
Expensive electronic infusion pumps are not a practical field solution because of their weight, cumbersome size and power requirements. Moreover, today's procedures for starting IV infusions on the battlefield are often dangerous because the attending medic must complete several time consuming steps. The labor intensive nature of current gravity solution bag modalities can prevent medics from attending to other patients also suffering from life threatening injuries. In some cases, patients themselves have been forced to hold infusion bags elevated in order to receive the medication by gravity drip.
With regard to the prior art, one of the most versatile and unique fluid delivery apparatus developed in recent years is that developed by one of the present inventors and described in U.S. Pat. No. 5,205,820. The components of this novel fluid delivery apparatus generally include: a base assembly, an elastomeric membrane serving as a stored energy means, fluid flow channels for filling and delivery, flow control means, a cover, and an ullage which comprises a part of the base assembly.
Another prior art patent issued to one of the present applicants, namely U.S. Pat. No. 5,743,879, discloses an injectable medicament dispenser for use in controllably dispensing fluid medicaments such as insulin, anti-infectives, analgesics, oncolylotics, cardiac drugs, bio-pharmaceuticals, and the like from a pre-filled vial at a uniform rate. The dispenser, which is quite dissimilar in construction and operation from that of the present invention, includes a stored energy source in the form of a compressively deformable, polymeric, elastomeric member that provides the force necessary to controllably discharge the medicament from a pre-filled container which is housed within the body of the device. After having been deformed, the polymeric, elastomeric member will return to its starting configuration in a highly predictable manner.
By way of brief summary, one form of the of the present invention for dispensing medicaments to a patient comprises a supporting structure, a semi-rigid, uniquely configured, collapsible unitary container carried by the supporting structure and defining a reservoir having an outlet, a first portion, a second portion and a tapered sidewall interconnecting the first and second portions, the sidewall varying in wall thickness from the first portion to the second portion, a stored energy source operably associated with the unitary container for controllably collapsing the container and an administration set including an administration line interconnected with the outlet port of the reservoir.
With the forgoing in mind, it is an object of the present invention to provide a compact, easy-to-use dispensing device that includes a uniquely configured fluid reservoir having a collapsible sidewall of progressively varying wall thickness that will deliver an injectable parenteral fluid contained within the fluid reservoir to the patient at a substantially constant flow rate.
Another object of the invention is to provide a fluid dispenser of the aforementioned character in which the collapsible sidewall is generally conical in shape.
Another object of the invention is to provide a fluid dispenser of the aforementioned character in which the collapsible sidewall is generally rectangular in shape.
Another object of the invention is to provide a fluid dispenser of the aforementioned character in which the collapsible sidewall is generally oval in shape.
Another object of the invention is to provide a dispenser in which a stored energy source is provided in the form of an elastic body, such as a coil spring that provides the force necessary to continuously and uniformly expel fluid from the uniquely shaped reservoir.
Another object of the invention is to provide a fluid dispenser as described in the preceding paragraphs which embodies a semi-rigid, pre-filled, unitary container that is constructed by a blow-fill-seal process and contains within the sealed reservoir of the container the beneficial agents to be delivered to the patient.
Another object of the invention is to provide a compact fluid dispenser as described in the preceding paragraph for use in controllably dispensing from the container reservoir, fluid medicaments, such as, antibiotics, blood clotting agents, analgesics, and like medicinals at a uniform rate.
Another object of the invention is to provide a fluid dispenser of the class described which is compact and lightweight, is easy for ambulatory patients to use, is fully disposable following its use and is extremely reliable in operation.
Another object of the invention is to provide a fluid dispenser of the character described in the preceding paragraphs in which the collapsible sidewall is tapered.
Another object of the invention is to provide a fluid dispenser of the character described in the preceding paragraphs in which the collapsible sidewall has a selectively varying fold depth.
Another object of the invention is to provide a fluid dispenser of the character described in the preceding paragraph in which the collapsible sidewall has a selectively varying fold pitch.
Another object of the invention is to provide a fluid dispenser of the character described in the preceding paragraphs in which the collapsible sidewall has a selectively varying fold angle.
Another object of the invention is to provide a fluid dispenser of the character described that is of a simple construction that can be used in the field with a minimum amount of training.
Another object of the invention is to provide a fluid dispenser of the class described that will permit infusion therapy to be initiated quickly, at will, at point of care on the battlefield so that the attending medic or medical professional can more efficiently deal with triage situations in austere environments.
Another object of the invention is to provide a fluid dispenser that, due to its pre-filled and self-contained packaging, is inherently less likely to result in an unintentional medication error by the attending pharmacist, nurse or other medical clinician.
Another object of the invention is to provide a fluid dispenser as described in the preceding paragraphs that is easy and inexpensive to manufacture in large quantities.
Definitions: As used herein, the following terms have the following meanings:
A closed container formed from a single component.
A wall having no break in uniformity or continuity.
An object or device that substantially recovers its original shape when released after being distorted.
A collapsible, expandable mechanical device constructed from metal, plastic or composite materials that recovers its original shape after being collapsed or extended
A virus, therapeutic serum, toxin, antitoxin, vaccine, blood, blood component or derivative, allergenic product, or analogous product applicable to the prevention, treatment or cure of diseases or injuries of the human or animal body.
A container that is designed and intended to be secure against the entry of microorganisms and to maintain the safety and quality of its contents after sealing.
As defined by the Food, Drug and Cosmetic Act, drugs are “articles (other than food) intended for the use in the diagnosis, cure, mitigation, treatment, or prevention of disease in man or other animals, or to affect the structure or any function.”
A finished dosage form (e.g. tablet, capsule, or solution) that contains the active drug ingredient usually combined with inactive ingredients.
Blood Substitutes are used to fill fluid volume and/or carry oxygen and other gases in the cardiovascular system. These include volume expanders for inert products, and oxygen therapeutics for oxygen-carrying products.
Infusion of hyperosmotic-hyperoncotic solutions such as hypertonic saline dextran (HSD) as used for resuscitation of traumatic shock and perioperative volume support or as an adjunct to other conventional isotonic crystalloid solutions. Where hypotension is caused by myocardial depression, pathological vasodilatation and extravascation of circulating volume due to widespread capillary leak, a resuscitative effort is attempted to correct the absolute and relative hypovolemia by refilling the vascular tree. Here resuscitation with a small volume of hypertonic-hyperoncotic solution allows systemic and splanchnic hemodynamic and oxygen transport recovery without an increase in pulmonary artery pressure. Alternate types of normotonic, hyperoncotic, hypertonic, and hypertonic-hyperoncotic solutions can be used for systemic hemodynamic recovery.
KVO—keeping-the-vein-open—in an IV set up. A phrase that refers to the flow rate of a maintenance IV line established as a prophylactic access.
Dietary supplemental enteral nutrition support feeding solutions used for nasoenteric application typically used in nasogastric, nasoduodenal, nasojejunal, or intravenous routes of administration.
The term ‘beneficial agent’ can include any substance or compound that is biologically active and includes any physiologically or pharmacologically active substance that produces a localized or systemic effect in humans or animals and that can be delivered by the present invention to produce a beneficial and useful result.
A liquid that which dilutes, as in an inert solution used to dilute a medicament. An inert liquid carrier of a beneficial agent.
A dispensing device in which one or more walls of the container are made of a material, which will deform (collapse) when pressure is applied thereto, or a dispensing device having a collapsible or telescoping wall structure.
The term ‘aseptic processing’ as it is applied in the pharmaceutical industry refers to the assembly of sterilized components and product in a specialized clean environment.
A sterile product is one that is free from all living organisms, whether in a vegetative or spore state.
The concept of aseptic blow-fill-seal (BFS) is that a container is formed, filled, and sealed as a unitary container in a continuous manner without human intervention in a sterile enclosed area inside a machine. The process is multi-stepped; pharmaceutical grade resin is extruded into a tube which is then formed into a container. A mandrel is inserted into the newly formed container and filled. The container is then sealed, all inside a sterile shrouded chamber. The product is then discharged to a non-sterile area for packaging and distribution.
An article of one-piece construction, or several parts that are rigidly secured together and is smoothly continuous in form and that any such components making up the part have been then rendered inseparable.
Referring now to the drawings and particularly to
Carried within reservoir housing 36 is a semi-rigid, reservoir-defining assembly, or unitary, pre-filled, hermetically sealed fluid container 40. As best seen by also referring to
As indicated in
In the preferred form of the invention unitary container 40 is formed in accordance with an aseptic blow-fill-seal manufacturing technique which is of a character well understood by those skilled in the art. This technique involves the continuous plastic extrusion through an extruder head of a length of parison in the form of a hollow tube between and through two co-acting first or main mold halves. The technique further includes the step of cutting off the parison below the extruder head and above the main mold halves to create an opening which allows a blowing and filling nozzle assembly to be moved downwardly into the opening in the parison for molding the molded container. Further details concerning the technique are available from Rommelag GMBH of Stuttgart, Germany and Weiler Engineering of Elgin, Ill.
As will be described in greater detail hereinafter, the reservoir 40a of the collapsible unitary container 40 is accessible via a penetrating member 58 that is adapted to pierce closure wall 50a as well as a pierceable slit septum 60, which is positioned within neck 54 and over closure wall 50a by means of a closure cap 62, which is affixed to the neck portion 54 of the container assembly by any suitable means such as adhesive bonding or sonic or heat welding.
The fluid contained within the pre-filled unitary container 40 can comprise by way of non-limiting example, a beneficial agent, a drug, a drug substitute, a blood volume expander, a resuscitation fluid, a biologic, blood, an artificial blood substitute, a blood plasma, a nutritional solution, a diluent and a saline solution.
Before discussing further the manner by which the reservoir 40a is accessed, a brief explanation of the importance of the unique shape of the unitary container 40 is in order. Referring to
As indicated in
In the apparatus of the present invention, the problem illustrated in
As depicted in
A1>A2>A3 and F1>F2>F3
Where the effective cross-sectional area of the container that the spring 65 is acting upon is continuously reduced as the container collapses. The unique design of the container and, in particular, the slope of the bellow-shaped sidewall 48 thereof will be configured according to the stress-strain profile of the stored energy source, or spring 65.
As previously discussed, another highly important feature of the present invention resides in the tailoring of the blow-fill-seal process used for making the container 40 to provide a unitary container having a tapered sidewall that exhibits a strategically varying wall thickness. More particularly, the blow-fill-seal process is tailored to provide a unitary container having a tapered sidewall that will be the thinnest at the widest part of the container. This aspect of the blow-fill-seal injection molding process uniquely yields a container that naturally collapses following an applied force starting at the widest portion, that is, the largest area. This will allow the container to exhibit novel collapse dynamics that are appropriately tuned to have an effective area to match the changing magnitude of the spring force.
Considering next the relationships between the various parameters required to design a container that will deliver fluid at constant pressure in the case that the force generating the pressure in the container varies linearly as the fluid is delivered from the container. For these considerations, it is assumed that the collapsing force is generated by a simple coiled spring as it extends from a compressed state. It is further assumed, for the purposes of this general example, that the container is circular in cross-section and that the force delivering the fluid decreases by a factor of 2 as the fluid is delivered from the container. Referring to
Assume that the relationship between the force and the extension of the spring is given by the expression:
F(y)=ky (1)
Where: the variable y represents the extension of the spring and k is the spring constant. For any value of y the relationship between the pressure, force and area is given by:
P=F(y)/A(y) (2)
Where: F(y) is the force delivered by the spring when the top of the bottle is at position y. A(y) is the cross-sectional area of the bottle at position y. P, the pressure, is independent of y.
The relationship between the cross-sectional area of the bottle and its radius as a function of the variable y is given by:
A(y)=πr(y)2 (3)
Using Equations (1), (2) and (3) it we may write:
y=πPr(y)2/k (4)
Rearranging Equation (3) yields an expression for r(y):
r(y)=(k/πP)1/2y1/2 (5)
This Equation shows that the radius varies as the square root of the position along the axis.
It can be shown that the volume, V0, of a container of the present invention (a container with the shape given by Equation (5)) between two values of y (y1 and y2) is given
V
0=(k/2P)(y12−y22) (6)
Where: P is the pressure in the system. Equations (4), (5) and (6) completely specify the container in terms of its shape and length. This can best be illustrated by way of the following two examples:
In Example 1, the delivery system design inputs consist of a particular spring (with a specified spring constant), a required container radius and a chamber pressure at which the dispenser will be operated. Therefore, a set of parameters defining the system can be set forth as follows:
The force constant of the spring: k=5 N/cm2
The radius of the container at the position y1:r1=2.54 cm
The pressure at which the system will operate: ½ atm=5 N/cm2
With these values Equation (4) yields a value of y1 as:
y
1=π(Pr12)/k=π(5)(2.54)2/5=20.3 cm
If we choose a second value of y, y2, to be the position where the force is ½ its value at y1 then we have using Equation 1 that y2=½ y1. So that:
y2=20.15 cm
And the length of the container, L, is then:
L=y
1
−y
2=10.15 cm.
Equation (5) gives the shape of the container as:
r(y)=(k/πP)1/2y1/2=(5/π5)1/2y1/2=(1/π)1/2y1/2 cm.
Equation (6) gives the volume of the container:
V
0=(½P)(y12−y22)=( 5/2)(⅕)(20.302−10.152)=½(411−103)=154 cm3
Thus, the fluid delivery system would have to have a length of 10.15 cm and a volume of approximately 154 ml—given that the designer wished to use a container with a radius of 2.54 cm, a spring with k=5 N/cm2 and a chamber pressure of 0.5 atm.
In Example 2, the delivery system design inputs consist of a particular spring (with a specified spring constant), a required container volume and a chamber pressure at which the dispenser will be operated. Therefore, the set of parameters can be set forth as follows:
The volume to be delivered: V0=250 cm3
The force constant of the spring: k=5 N/cm
The pressure at which the system will operate: P=½ atm=5 N/cm2
For this example we must first solve for y1 in terms of V0 We have assumed that: y2=(½)y1. So that Equation (6) yields:
V
0(k/2P)(y12−y22)=(k/2P)(y12−(½)2y12)=(⅜)(k/P)y12
This gives the value of
y
1=( 8/3)1/2(V0P/k)1/2=( 8/3)1/2(250(5)/5)1/2=((8)( 250/3))1/2=25.82 cm.
And
y
2=(½)(y1)=25.82/2=12.91 cm
Thus, the length of the container is: L=25.82−12.91=12.91 cm
The shape of the container is given by Equation (4):
r(y)=(k/πP)1/2y1/2=(5/π5)1/2y1/2=(1/π)1/2y1/2
The radius of the container at position #1 can be obtained using Equation (5) and setting y=25.82:
r(y1)=(1/π)1/2(25.82)1/2=(25.82/π)1/2=2.86 cm
And the radius of the container at position #2 is:
r(y2)=(1/π)1/2(12.91)1/2=(12.91/π)1/2=2.03 cm
Thus, the container decreases in radius from 2.86 cm to 2.03 cm from the base of the container (contacting the spring) to the tip of the container. In either example, the basic outer shape of the container could also be realized by employing Equation (5).
Referring once again to
The reservoir accessing means, which will be discussed in greater detail hereinafter, here comprises a septum-penetrating assembly 70, which includes the previously identified penetrating member 58 (
Selector member housing 72 is retained in its first position by a tear strip 79 that is removably receivable between a circumferentially extending rib 72a formed on housing 72 and the upper extremity 76b of guide sleeve 76. When the tear strip 79 is removed in the manner illustrated in
Considering now in greater detail the rate control assembly 80 of this latest form of the invention, as shown in
As best seen by referring to
With the device in the configuration shown in
In the manner previously described, movement within guide sleeve 76 of the selector member housing 72, along with septum-penetrating assembly 70 from the first position shown in
To recover any medicament that may remain in reservoir 40a following the fluid delivery step, a pierceable septum 116, which is carried by selector member 92, can be conveniently pierced using a conventional syringe or like device (not shown). Piercing of septum 116 opens communication between reservoir 40a and the syringe via central passageway 118 of the selector member 92, via the rate control assembly 80 and via passageway 58a of penetrating member 58 so that any remaining medicament can be readily recovered from reservoir 40a.
Turning now to
Carried within reservoir housing 36 is a semi-rigid, reservoir-defining assembly, or unitary, pre-filled, hermetically sealed fluid container 122 that is of a somewhat different configuration. More particularly, as will be described in greater detail hereinafter, 122 here comprises a unique tapered, generally bellows shaped, nestable sidewall generally designated by the numeral 124. As illustrated in
In this latest embodiment of the invention, for the effective area of the unitary container 122 to be reduced as the stored energy source, or spring 65 (
Referring to
Turning next to
It is also to be observed that the strategic taper angle of the unitary container 122 comprises the central feature that serves to change the effective area of the unitary container-spring interface. More particularly, each successive fold of the container sidewall uniquely nests in a manner previously described, the effective container diameter (and hence the area) increasingly reduces the effective container diameter, the chamber pressure will then be effectively tailored to accommodate the spring dynamics. In this regard, the interior taper, which is designated in
In addition to the thinner walled folds collapsing in priority, the design of a given fold, that is the varying radius of curvature of the fold and the varying fold angle (see
With the device in the configuration shown in
In the manner previously described, movement within guide sleeve 76 of the selector member housing 72, along with septum-penetrating assembly 70 from the first position shown in
As the sidewall of the unitary container collapses, the fluid contained within reservoir 124a will flow into passageway 58a of the penetrating member 58. From passageway 58a the fluid will flow, and the manner previously described through conventional particulate filter 82, and into the rate control assembly which is substantially of identical construction and operation to that previously described. From the rate control assembly, the medicinal fluid will flow into the various circumferentially spaced-apart fluid passageways formed in the selector housing 72 and then on to the patient via the administration set 68 (see
As was the case in the earlier described embodiment of the invention, to recover any medicament that may remain in reservoir 124a following the fluid delivery step, a pierceable septum 116, which is carried by selector member 92, can be conveniently pierced using a conventional syringe or like device (not shown).
Referring next to
Turning to
Having now described the invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difficulty in making changes and modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.
