Patent Application
20080021419
The present invention relates to a single-use medical device and more particularly to a two-piece ophthalmic drug delivery device with a disposable tip end containing an improved plunger linkage and seal.
Several diseases and conditions of the posterior segment of the eye threaten vision. Age related macular degeneration (ARMD), choroidal neovascularization (CNV), retinopathies (e.g., diabetic retinopathy, vitreoretinopathy), retinitis (e.g., cytomegalovirus (CMV) retinitis), uveitis, macular edema, glaucoma, and neuropathies are several examples.
These, and other diseases, can be treated by injecting a drug into the eye. Such injections are typically manually performed using a conventional syringe and needle.
In using such a syringe, the surgeon is required to pierce the eye tissue with the needle, hold the syringe steady, and actuate the syringe plunger (with or without the help of a nurse) to inject the fluid into the eye. Fluid flow rates are uncontrolled. Reading the vernier is also subject to parallax error which affects the precision and accuracy of the injected volume. Tissue damage may occur due to an “unsteady” injection. Reflux of the drug may also occur when the needle is removed from the eye.
An effort has been made to control the delivery of small amounts of liquids. A commercially available fluid dispenser is the ULTRA™ positive displacement dispenser available from EFD Inc. of Providence, R.I. The ULTRA dispenser is typically used in the dispensing of small volumes of industrial adhesives. It utilizes a conventional syringe and a custom dispensing tip. The syringe plunger is actuated using an electrical stepper motor and an actuating fluid. With this type of dispenser, the volumes delivered are highly dependent on fluid viscosity, surface tension, and the specific dispensing tip. Parker Hannifin Corporation of Cleveland, Ohio distributes a small volume liquid dispenser for drug discovery applications made by Aurora Instruments LLC of San Diego, Calif. The Parker/Aurora dispenser utilizes a piezo-electric dispensing mechanism. While precise, this dispenser is expensive and requires an electrical signal to be delivered to the dispensing mechanism.
U.S. Pat. No. 6,290,690 discloses an ophthalmic system for injecting a viscous fluid (e.g. silicone oil) into the eye while simultaneously aspirating a second viscous fluid (e.g. perflourocarbon liquid) from the eye in a fluid/fluid exchange during surgery to repair a retinal detachment or tear. The system includes a conventional syringe with a plunger. One end of the syringe is fluidly coupled to a source of pneumatic pressure that provides a constant pneumatic pressure to actuate the plunger. The other end of the syringe is fluidly coupled to an infusion cannula via tubing to deliver the viscous fluid to be injected.
It would be desirable to have a portable hand piece for injecting a drug into the eye. Such a hand piece includes a limited reuse assembly attachable to and removable from a disposable tip segment. The disposable tip segment contains the drug, a needle for administering the drug, a plunger, and various other components. The limited reuse assembly includes a mechanism for driving the plunger to expel the drug from the disposable tip segment. The actuation of the plunger in the disposable tip segment is controlled by the limited reuse assembly. It would be desirable to have a plunger linkage and seal that maintains the sterility of the disposable tip segment and prevents reflux when the needle is removed from the eye after an injection.
In one embodiment consistent with the principles of the present invention, the present invention is a method of injecting a substance into an eye. An input is received. In response to the input, a mechanical linkage interface is advanced until a mating surface on an end of the mechanical linkage interface contacts a plunger interface on an end of the plunger. The mechanical linkage interface is further advanced, thereby advancing the plunger to expel a substance contained in a dispensing chamber. The mechanical linkage interface is retracted without substantially retracting the plunger to prevent reflux of the substance.
In another embodiment consistent with the principles of the present invention, the present invention is a method of operating an ophthalmic injection system. A connection between a disposable tip segment and a limited reuse assembly is recognized. A temperature control device is activated to alter the temperature of a substance contained in a dispensing chamber. Dosage information is read. In response to the dosage information, a mechanical linkage interface is advanced to advance a plunger to expel the substance from the dispensing chamber. The mechanical linkage interface is retracted without substantially retracting the plunger to prevent reflux of the substance. Reuse of the disposable tip segment is prevented. The removal of the disposable tip segment from the limited reuse assembly is recognized.
In another embodiment consistent with the principles of the present invention, the present invention is a method of injecting a drug into an eye. A connection between a disposable tip segment and a limited reuse assembly is recognized. A temperature control device is activated to alter the temperature of a drug contained in a dispensing chamber. An input from a thermal sensor is received. The temperature control device is controlled based on the input from the thermal sensor. An indication that the drug is at the proper temperature and ready to be delivered into an eye is provided. A mechanical linkage interface is advanced until a mating surface on an end of the mechanical linkage interface contacts a plunger interface on an end of the plunger. The mechanical linkage interface is further advanced to advance the plunger to expel a substance contained in a dispensing chamber. The mechanical linkage interface is retracted without substantially retracting the plunger to prevent reflux of the substance. Removal of the disposable tip segment from the limited reuse assembly is recognized.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed. The following description, as well as the practice of the invention, set forth and suggest additional advantages and purposes of the invention.
The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.
Reference is now made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying figures. Wherever possible, the same reference numbers are used throughout the figures to refer to the same or like parts.
Tip segment 205 is capable of being connected to and removed from limited reuse assembly 250. In this embodiment, tip segment 205 has a threaded portion on an interior surface of housing 215 that screws onto the threaded portion 260 of limited reuse assembly 250. In addition, lock mechanism 265 secures tip segment 215 to limited reuse assembly 250. Lock mechanism 265 may be in the form of a button, a sliding switch, or a cantilevered mechanism. Other mechanisms for connecting tip segment 205 to limited reuse assembly 250, such as those involving structural features that mate with each other, are commonly known in the art and are within the scope of the present invention.
Needle 210 is adapted to deliver a substance, such as a drug, into an eye. Needle 210 may be of any commonly known configuration. Preferably, needle 210 is designed such that its thermal characteristics are conducive to the particular drug delivery application. For example, when a heated drug is to be delivered, needle 210 may be relatively short (several millimeters) in length to facilitate proper delivery of the drug based on thermal characteristics.
Switch 270 is adapted to provide an input to the system. For example, switch 270 may be used to activate the system or to turn on a heater. Other switches, buttons, or user-directed control inputs are commonly known and may be employed with limited reuse assembly 250 and/or tip segment 205.
Optional light 275 is illuminated when tip segment 205 is ready to be used. Optional light 275 may protrude from housing 215, or it may be contained within housing 215, in which case, optional light 275 may be seen through a clear portion of housing 215. In other embodiments, optional light 275 may be replaced by an indicator, such as a liquid crystal display, segmented display, or other device that indicates a status or condition of disposable tip segment 205. For example, optional light 275 may also pulse on and off to indicate other states, such as, but not limited to a system error, fully charged battery, insufficiently charged battery or faulty connection between the tip segment 205 and limited use assembly 250. While shown on tip segment 205, optional light 275 or other indicator may be located on limited reuse assembly 250.
In the embodiment of
In various embodiments of the present invention, temperature control device 450 is a heating and/or a cooling device. Temperature control device 450 is in thermal contact with dispensing chamber housing 425. As such, temperature control device 450 is capable of changing the temperature of the substance in dispensing chamber 405.
Assembly 555 can include any of a number of different components. In one embodiment, assembly 555 contains a fuse that is blown when the heat button is activated or after disposable tip segment 205 is used. In this manner, the fuse prevents reuse of disposable tip segment 205. In another embodiment, assembly 555 includes a memory device that stores information about the type of disposable tip segment 205, dosage information, temperature information, plunger movement information, or any other type of information that identifies a characteristic of disposable tip segment 205 or a manner in which disposable tip segment 205 is operated. In other embodiments, assembly 205 includes a hard-wired memory device, like a NAND flash IC, an RFID tag, a hard-wired wired circuit that can store a representation of data, like a series of fuses and resistors connected in parallel, or other type of device.
A substance to be delivered into an eye, typically a drug, is located in dispensing chamber 405. In this manner, the substance is contacted by the inner surface of dispensing chamber housing 425 and one face of plunger 415. Typically, dispensing chamber 405 is cylindrical in shape. Temperature control device 450 is in thermal contact with dispensing chamber housing 425. In this manner, temperature control device 450 is adapted to control the temperature of the contents of dispensing chamber 425. Thermal sensor 460 provides temperature information to assist in controlling the operation of temperature control device 450.
In one embodiment of the present invention, the substance located in dispensing chamber 405 is a drug that is preloaded into the dispensing chamber. In such a case, disposable tip segment 205 is appropriate as a single use consumable product. Such a disposable product can be assembled at a factory with a dosage of a drug installed.
When a drug is preloaded into dispensing chamber 405, a set quantity of the drug can be preloaded. For example, 100 microliters of a drug can be loaded into dispensing chamber 405, and any quantity up to 100 microliters can be dispensed. Information about the amount of drug in dispensing chamber 205 and other dosage information can be stored in assembly 555. In such a case, the plunger 415 can be moved a precise distance to deliver a precise dosage of drug from the dispensing chamber 405, through the needle 210, and into an eye. This provides for flexibility of dosing and for ease of assembly.
In tip segment 205, plunger interface 420 is located on one end of plunger 415. The other end of plunger 415 forms one end of dispensing chamber 405. Plunger 415 is adapted to slide within dispensing chamber 405. An outer surface of plunger 415 is fluidly sealed to the inner surface of dispensing chamber housing 425. Dispensing chamber housing 425 surrounds the dispensing chamber 405. Typically, dispensing chamber housing 425 has a cylindrical shape. As such, dispensing chamber 405 also has a cylindrical shape. In tip segment 205, assembly 555 includes any number of components as previously described.
Needle 210 is fluidly coupled to dispensing chamber 405. In such a case, a substance contained in dispensing chamber 405 can pass through needle 210 and into an eye. Temperature control device 450 at least partially surrounds dispensing chamber housing 425. In this case, temperature control device 450 is adapted to heat and/or cool dispensing chamber housing 425 and any substance contained in dispensing chamber 405. Interface 530 connects temperature control device 450 with tip interface connector 520.
The components of tip segment 205, including dispensing chamber housing 425, temperature control device 450, and plunger 415 are at least partially enclosed by tip segment housing 215. In one embodiment consistent with the principles of the present invention, plunger 415 is sealed to the interior surface of dispensing chamber housing 425. This seal prevents contamination of any substance contained in dispensing chamber 405. For medical purposes, such a seal is desirable. This seal can be located at any point on plunger 415 or dispensing chamber housing 425.
In limited reuse assembly 250, power source 310 provides power to actuator 515. An interface (not shown) between power source 310 and actuator 515 serves as a conduit for providing power to actuator 515. Actuator 515 is connected to actuator shaft 510. When actuator 515 is a stepper motor, actuator shaft 510 is integral with actuator 515. Mechanical linkage interface 545 is connected to actuator shaft 510. In this configuration, as actuator 515 moves actuator shaft 510 upward toward needle 210 mechanical linkage interface 545 also moves upward toward needle 210.
Controller 305 is connected via interface 535 to limited reuse assembly interface connecter 525. Limited reuse assembly interface connecter 525 is located on a top surface of limited reuse assembly housing 255 adjacent to mechanical linkage interface 545. In this manner, both limited reuse assembly interface connector 525 and mechanical linkage interface 545 are adapted to be connected with tip interface connector 520 and plunger interface 420 respectively.
Controller 305 and actuator 515 are connected by an interface (not shown). This interface (not shown) allows controller 305 to control the operation of actuator 515. In addition, an interface (not shown) between power source 310 and controller 305 allows controller 305 to control operation of power source of 310. In such a case, controller 305 may control the charging and the discharging of power source 310 when power source 310 is a rechargeable battery.
Controller 305 is typically an integrated circuit with power, input, and output pins capable of performing logic functions. In various embodiments, controller 305 is a targeted device controller. In such a case, controller 305 performs specific control functions targeted to a specific device or component, such as a temperature control device or a power supply. For example, a temperature control device controller has the basic functionality to control a temperature control device. In other embodiments, controller 305 is a microprocessor. In such a case, controller 305 is programmable so that it can function to control more than one component of the device. In other cases, controller 305 is not a programmable microprocessor, but instead is a special purpose controller configured to control different components that perform different functions. While depicted as one component in
Tip segment 205 is adapted to mate with or attach to limited reuse assembly 250 as previously described. In the embodiment of
In operation, when tip segment 205 is connected to limited reuse assembly 250, controller 305 controls the operation of actuator 515. Actuator 515 is actuated and actuator shaft 510 is moved upward toward needle 210. In turn, mechanical linkage interface 545, which is mated with plunger interface 420, moves plunger 415 upward toward needle 210. A substance located in dispensing chamber 405 is then expelled through needle 210.
In addition, controller 305 controls the operation of temperature control device 450. Temperature control device 450 is adapted to heat and/or cool an outside surface of dispensing chamber housing 425. Since dispensing chamber housing 425 is at least partially thermally conductive, heating or cooling dispensing chamber housing 425 heats or cools a substance located in dispensing chamber 405. Temperature information can be transferred from thermal sensor 460 through interface 530, tip interface connector 520, limited reuse assembly interface connector 525, and interface 535 back to controller 305. This temperature information can be used to control the operation of temperature control device 450. When temperature control device 450 is a heater, controller 305 controls the amount of current that is sent to temperature control device 450. The more current sent to temperature control device 450, the hotter it gets. In such a manner, controller 305 can use a feed back loop utilizing information from thermal sensor 460 to control the operation of temperature control device 450. Any suitable type of control algorithm, such as a proportional integral derivative (PID) algorithm, can be used to control the operation of temperature control device 450.
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The plunger 415 of
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The various configurations of
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When dispensing chamber 405 contains a drug that is to be delivered into an eye, the various configurations of
From the above, it may be appreciated that the present invention provides an improved system and methods for delivering precise volumes of a substance into an eye. The present invention provides a single use, disposable delivery device tip segment that is capable of delivering a precise dosage. The tip segment interfaces with a limited reuse assembly. The disposable tip segment has a plunger interface that mates with a mechanical linkage interface. The plunger interface and mechanical linkage interface are designed to prevent reflux of the substance when the needle is removed from the eye. The present invention is illustrated herein by example, and various modifications may be made by a person of ordinary skill in the art.
While the present invention is described in the context of a single-use drug delivery device, the present invention encompasses any single-use medical device that interfaces with a source of electric power. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
This Application is a continuation-in-part of U.S. patent application Ser. No. 11/581,629 filed Oct. 16, 2006, U.S. patent application Ser. No. 11/581,630 filed Oct. 16, 2006, U.S. patent application Ser. No. 11/581,591 filed Oct. 16, 2006, and U.S. patent application Ser. No. 11/435,906 filed May 17, 2006.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11435906 | May 2006 | US |
| Child | 11833518 | Aug 2007 | US |
