WO2001000261A1

WO2001000261A1 - Syringe for transfer of medication from a prefilled medication container

Info

Publication number: WO2001000261A1
Application number: PCT/US2000/017765
Authority: WO
Inventors: Thomas E. Dudar; Ronald A. Tomlinson; Dustin C. Cawthon
Original assignee: Baxter International Inc.
Priority date: 1999-06-30
Filing date: 2000-06-28
Publication date: 2001-01-04
Also published as: AU5774500A; EP1107806A1

Abstract

A liquid transfer device (10) for use with a medication container (16) is used in the delivery of medication. It includes a plunger (12) having a discharge end (13), a loading end (26), and interior space configured for receiving the medication container, and a through connector (30) for engaging an engaging end (20) of the medication container (16). The through connector (30) has an opening (36) defining a medication flow path from the container to the discharge end. A check valve (32) prevents medication backflow. A barrel (14) defines a bore (34) and has a discharge end (28), a loading end (26), and is dimensioned for slidably accommodating the plunger (12) such that the plunger is movable between a depressed and a retracted position. A piston (37) is on the plunger (12) to slidingly and sealingly engage the barrel. A tip protector (38) is disposed at the barrel discharge end (28) to create a vacuum in the barrel when the plunger is retracted. Upon the engagement of the medication container (16) by the through connector (30), and the plunger (12) being moved toward the retracted position with the tip protector (38) in place, the medication is withdrawn into the barrel. When the tip protector (38) is removed and the plunger (12) depressed, the medication is propelled from the barrel (14).

Description

SYRINGE FOR TRANSFER OF MEDICATION FROM A PREFILLED MEDICATION CONTAINER

DESCRIPTION

The present invention is a combination of a medication container and a delivery device configured to facilitate aseptic fluid transfer first from the medication container to the delivery device and then from the delivery device to a receiver. More specifically, the delivery device preferably possesses attributes of a standard syringe. Medication containers suitable for use with the present delivery device preferably possess attributes of a standard medication container, such as a plastic ampule.

BACKGROUND ART Syringes are widely used to deliver medical fluids directly to a patient or other receiver, such as an i.v. bag, bottle, tubing or catheter. Most syringes are supplied empty and the user must aseptically transfer fluid from a medication container, such as a vial or ampule, into the syringe prior to dispensing.

Although prefilled syringes are commercially available, they are difficult to manufacture, and hence expensive. Prefilled syringes pose sterility challenges during production, shipping and storage. They also pose stability issues due to chemical and physical interactions between the stored solution and the materials of the various syringe components, such as rubber pistons, and lubricous coatings, such as silicone. Many prefilled syringes require either placement into reusable holders or assembly of disposable plunger rods, both inconvenient and time-consuming for the end user. Those prefilled syringes that come with preassembled plunger rods are bulky and raise concerns about piston movement during shipping and storage.

For all of the above reasons, most syringes are supplied empty. In addition, pharmaceutical companies prefer to supply their drugs in simple, inexpensive standard packaging such as vials or ampules. Pharmacies prefer to simply stock and dispense these compact ampules and vials, relying on the end user to stock all other necessary supplies and to perform the transfer and delivery steps. Hence, the end user is burdened with performing various transfer steps prior to dispensing. This process is fraught with risks to both the patient and care provider.

Patients are subject to a variety of clinical risks. Medication errors can occur if an empty syringe is not properly labeled after being filled. Catheters can be ruptured or veins can be damaged due to excessive pressure if an inappropriately sized syringe is used to bolus a patient. This also can occur with small prefilled syringes. Solutions can become contaminated with microorganisms, leading to patient infections if aseptic techniques are not employed during transfer and dispensing. For example, microorganisms can be pushed into a vial if the rubber stopper is not adequately disinfected prior to accessing with a needle and syringe. Also, the routine practice of injecting a volume of ordinary room air into the vial prior to withdrawing an equal volume of liquid can result in contaminating the vial=s contents. This is even more of an issue with multidose vials, which can infect multiple patients if they become contaminated. Glass or rubber particles can be introduced into the medication when the neck of a glass ampule is snapped open or when a needle cores the rubber stopper of a vial. Also, precious time can be lost if an emergency situation arises and medication must be drawn up from a vial or ampule.

Likewise, care providers are subject to risks associated with the transfer process. Glass ampules pose a laceration risk and needle stick injuries can occur when accessing vials and ampules. Needle stick injuries can be avoided by using needleless i.v. access systems; however, the prevalence of empty syringes with preattached needles still poses a risk to those who choose not to consistently employ these safety devices. Also, certain drugs can cause serious injury if inadvertently contacted or inhaled. This can occur when a vial=s contents become over-pressurized and leak during the routine practice of injecting a volume of air into the vial prior to withdrawing an equal volume of liquid. For these reasons, expensive chemotherapy vial dispensing pins with air venting filters are available to reduce the risk of exposure during the transfer process.

While not as serious as the above mentioned health risks, care providers are inconvenienced by this transfer process. They must gather supplies from two different sources: vials (or ampules) from the pharmacy, and empty syringes, needles (or needleless accessories) and alcohol wipes from central supply. They must perform time consuming multiple transfer steps, taking care to avoid the risks previously mentioned. After dispensing, they must then dispose of the considerable packaging waste in the regular trash, and the used syringe, needle and vial (or ampule) in a sharps container.

These risks are magnified if the care provider is not a trained medical professional, as is often the case in a home care environment.

Recently, plastic ampules have been commercialized as an alternative medication container to glass ampules and vials. These plastic ampules still require the use of a separate syringe, but needles are eliminated from the transfer process. The user must aseptically break off a frangible cover and carefully press fit the sterile luer tip of the syringe into the sterile open neck of the ampule. If the user does not perfectly align the luer tip during this docking step, the tip will contact the non-sterile exterior surfaces immediately adjacent the neck interior. The transfer process is further complicated by the resiliency of the ampule. Unless the user forcibly restrains the syringe plunger, liquid will be drawn back into the ampule. Most of the other issues identified previously are not resolved by this system.

Finally, Vital Signs Inc., has introduced VASCEZE ™, a blow, fill, seal plastic medication container that doubles as the delivery device. Like a prefilled syringe, no transfer steps are required. However, unlike a prefilled syringe, the VASCEZE™ device lacks many of the clinically necessary attributes of a syringe.

Accordingly, it is an object of this invention to provide an improved medication delivery system that enhances the transfer and delivery of fluid from a prefilled medication container.

It is another object of this invention to provide an improved medication delivery system that retains the clinical and manufacturing benefits of a standard medical syringe as the delivery device.

It is another object of this invention to provide an improved medication delivery system that retains the clinical and manufacturing benefits of standard medication containers.

It is a further object of this invention to provide an improved medication delivery system that reduces the clinical risks to the patient and/or care providers associated with using standard medication containers and syringes. It is still another object of this invention to provide an improved medication delivery system that reduces the inconveniences to the care provider associated with using standard medication containers and syringes, including providing a separate medication container and a separate syringe in a single compact device that requires less space during shipping, storage, dispensing, use and disposal.

It is yet another object of this invention to provide an improved medication delivery system capable of mixing two pre -measured doses of medication within the syringe. DISCLOSURE OF INVENTION The above-listed objects are met or exceeded by the present contamination-resistant medication delivery system which features a syringe with a plunger designed to receive a medication container. The unit is activated by pushing the medication container against a through connector inside the plunger. When the plunger is retracted, the medication is drawn into the syringe barrel and is ready to be administered. Thus, a sterilized medication container or ampule may be loaded and the contents emptied into a syringe without being subject to contamination, since only the end of the container opposite the delivery end is contacted by the care provider.

More specifically, a liquid transfer device for use with a medication container in the delivery of medication includes a plunger having a discharge end, a loading end, an interior space configured for receiving the medication container, and a through connector for engaging a mating end of the medication container. The through connector has an opening which is placed in fluid communication with the medication container, and a one-way valve in the opening for preventing backflow of the medication. The plunger is configured such that when the medication container is engaged with the through connector, the medication flows from the medication container and into a barrel.

Also provided is a barrel defining a bore and having a discharge end, a loading end, and being dimensioned for slidably accommodating the plunger therein between a depressed and a retracted position. A seal or piston is disposed on an exterior of the plunger at the plunger discharge end and is configured to slidingly and sealingly engage the barrel. A tip protector is sealingly disposed at the discharge end of the barrel, such that when the plunger moves within the barrel toward the retracted position, a vacuum is created in the barrel. Upon the establishment of fluid communication between the medication container and the through connector, and the plunger being moved toward the retracted position with the tip protector in place, the medication is withdrawn from the medication container into the barrel. When the tip protector is removed and the plunger is pushed toward the depressed position, the medication is propelled through the discharge end of the barrel.

Features of this system enhance the transfer and delivery of fluid from a prefilled medication container by providing a transfer system that is sterile, yet does not require the use of needles by care providers. When a sharp edge is used to puncture the medication container and establish fluid communication, it is contained deep within the plunger, safely enclosed within its walls. Care providers can therefore safely handle the device without likelihood of needle stick injuries.

The design of the present invention allows the medication container to fit inside the plunger of the syringe, forming a more compact unit than those of the prior art. The syringe and the medication container need not be stored or shipped separately. The devices can be pre-packaged from the manufacturer with the medication container in place within the plunger. Thus, the loaded syringe will take up little to no more storage and shipping space than the syringe alone. Further, the entire assembly can be sterilized as a unit. An alternative embodiment allows the end user to aseptically load a separate medication container into an empty plunger bore. In yet another embodiment, the syringe does not contain a separate plunger. Instead, the medication container is configured to allow it to also serve as the plunger.

Risks to patients are reduced by this delivery system as well. Contamination risks are reduced because the medication and the delivery system is received sterilized. Use of this system allows for few opportunities to introduce contaminants into the system. The patient is protected from dosage errors because the medication containers are premeasured. In emergency situations, the patient also gains precious time, because this system eliminates the time-consuming steps of measuring out dosages, lining up particular fittings or installing a needle to effect the transfer.

Yet another feature of this delivery system is its ability to mix medications within the delivery system. The device of this invention can be manufactured with a second medication in either liquid or powdered form, premeasured and loaded into the barrel of the syringe. This second medication is then mixed, activated or diluted with the liquid medication in the medication container. The present design also provides a system that is easy to use and still maintain sterility of the medication. Because the plunger acts as physical barrier between the medication container and the barrel, any nonsterile exterior surface of the medication container never touches any surface that is contacted by the medication. The medication flows directly from the medication container into the barrel. Thus, the medication container can be easily handled and placed into the plunger without risk of contacting and contaminating surfaces that will be placed in contact with the medication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the present syringe and a medication container;

FIG. 2 is a vertical sectional view of the syringe and medication container of FIG. 1, shown assembled;

FIG. 3 is a vertical sectional view of an alternate embodiment of the syringe and medication container of FIG. 1; FIG. 4 is a vertical sectional view of another alternate embodiment of the syringe and medication container of FIG. 1;

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 2 and in the direction generally indicated; FIG. 6A is a vertical sectional view of the present syringe and container as received from the manufacturer;

FIG. 6B is a vertical sectional view of the present syringe and container with the protective cap removed and the medication container pushed into the plunger for effecting fluid communication;

FIG. 6C is a vertical sectional view of the present syringe and container after the medication has been transferred into the syringe barrel;

FIG. 6D is a vertical sectional view of the present syringe and container after the protective tip cover has been removed and the syringe is ready to deliver the medication;

FIG. 6E is a vertical sectional view of the present syringe and container after the medication has been delivered

FIG. 7A is a vertical sectional view of still another alternate embodiment of the present syringe as received from the manufacturer; FIG. 7B is a vertical sectional view of the syringe of FIG. 7 A shown with the plunger retracted and the medication forced into the barrel;

FIG. 7C is a vertical sectional view of the syringe of FIG. 7A shown with the plunger depressed and the medication administered;

FIG. 8A is a vertical sectional view of a further alternate embodiment of the present syringe shown as received from the manufacturer;

FIG. 8B is a vertical sectional view of the syringe of FIG. 8A shown with the plunger retracted and the medication forced into the barrel;

FIG. 8C is a vertical sectional view of the syringe of FIG. 8 A shown with the plunger depressed and the medication administered; FIG. 9A is a vertical section of yet a further alternate embodiment of the present syringe shown as received from the manufacturer;

FIG. 9B is a vertical section of the syringe of FIG. 9B shown with the medication container punctured; FIG. 9C is a vertical section of the syringe of FIG. 9 A shown with the plunger retracted; and

FIG. 9D is a vertical section of the syringe of FIG. 9 A shown with the plunger depressed and the medication administered.

BEST MODE OF CARRYING OUT THE INVENTION

Referring to FIGs. 1 and 2, a liquid delivery device or syringe, generally designated 10, is provided for the transfer of sterile, dosage-controlled medication. The syringe 10 is preferably provided with a plunger, generally designated 12, nested inside a barrel, generally designated 14, of the syringe in a compact, depressed position (best seen in FIG. 2). A pre-filled medication container, such as an ampule, generally designated 16, is inserted into the plunger before use.

The medication container 16 is defined by at least one wall 18 and at least one preferably puncturable engaging end 20. The container 16 is obtainable from a variety of pharmaceutical or medical supply sources, and can be made of rigid materials such as glass, or of flexible or semi-rigid plastics or elastomers. It may be cylindrical or any shape that will conveniently fit inside the plunger 12. The wall 18 is preferably made of a flexible material, so that it will collapse when a medication 22 is drawn from the medication container 16. However, when the wall 18 is constructed of a rigid material, such as glass, then the medication container 16 will need either to be vented through the container or to contain a sterile air space in order to efficiently remove the entire dose of medication 22, as is known in the art. The puncturable engaging end 20 must be made of a plastic material, such as an elastomer, that can be punctured when engaged with the plunger 12 as described below.

Plastic blow, fill, seal containers 16 are preferred. It is desirable to offset a parting line 23 on the end of the blow, fill, seal container 16 to avoid the parting line interfering with the engagement of a through connector 30. Glass or plastic vials or cartridges incoφorating elastomeric closures as the engaging end 20 are also contemplated. Furthermore, glass or plastic tubes with internal sliding or fixed piston members may also be used. Extruded, filled and sealed plastic tubing, bags or balloons could also be used as a medication container 16. It is also contemplated that the choice of the medication container 16 will require modification of the plunger 12 and the through connector 30 to insure compatibility.

The plunger 12 has a smaller diameter discharge end 13 with an opening 24. Preferably, the plunger 12 may be made of any material that will form a suitable barrier with the barrel 14, and which will withstand the stress and pressure when the plunger 12 is retracted toward a loading end 26 of the barrel and depressed toward a discharge end 28 of the barrel. Various plastics may be used to make the plunger 12. Glass can also be used. Use of plastics will result in a lighter weight and less expensive product, but other materials can be used where warranted. The plunger 12 can be made in any general shape that will conveniently fit inside the barrel 14 and will accommodate the medication container 16. Preferably, the plunger 12 can be designed to accept various sizes and types of medication containers 16. The main functions of the plunger 12 are to separate the outside of the medication container 16 from the inside of the barrel 14, and to provide the force necessary to withdraw the medication 22 from the container and also to push the medication 22 through an opening 29 in the discharge end 28 of the barrel. In handling the medication container 16, it is difficult to maintain sterile conditions on the exterior of the container while inserting it into the plunger 12. Because the plunger 12 acts as a sterile barrier between the exterior of the container 16 and part of the barrel 14 which will contact the medication 22, it is not necessary to keep the outside of the medication container sterile except for the engaging end 20. However, the medication 22 must be sterile within the container 16. The plunger 12 also preferably provides a sterile barrier at the interface between a loading end 40 of the plunger 12 and the barrel 14. This can be accomplished in a variety of ways, such as by molding a sealing ring 41 (FIG. 3) onto the outer surface of the plunger 12 at its loading end 40 or on the inner surface of the barrel 14, and dimensioning it to provide a sterile barrier which protects the gap between the plunger and the barrel. Alternatively, the outside dimension of the loading end 40 of the plunger 12 can be shaped such that it press fits into the opening of the barrel 14 when fully depressed. Likewise, the surface of the plunger 12 can form a butt seal against a finger flange 31. Also, an extension can be molded into the finger flange 31 of the plunger 12 that seals against the outside of the barrel 14.

The plunger 12 also preferably provides a sterile barrier 41a (best seen in FIG. 3) at the interface between the plunger 12 and the medication container 16. This can be accomplished in a variety of ways, such as by molding a sealing ring onto the inner surface of the plunger 12 near the finger flange 31 , and by dimensioning it to provide a sterile barrier at this point. Alternatively, the medication container 16 can include a similar feature that interfaces with the interior surface of the plunger 12 to protect the gap or space between the container 16 and the inside surface of the plunger 12. Such structure is also preferably configured to properly position the medication container 16 during storage to prevent premature engagement.

When the medication 22 leaves the medication container 16, it does not flow into the plunger 12, but rather follows a flow path defined by the through connector 30 (best seen in FIG. 2), a check valve 32 and through the plunger opening 24. Only then does it flow into the barrel 14. Thus, except for the engaging end 20, the outside of the medication container 16 never touches any part of the syringe 10 that touches the medication 22.

The discharge end 28 of the barrel 14 can be any useful type of nozzle, such as a standard medical luer slip or luer lock. Alternatively, it could include an integral or preattached sharp or blunt needle or sharp or blunt cannula. The discharge end 28 can also include any special device to access drug vial stoppers.

Functionally, the through connector 30 engages the medication container 16 and serves as a fluid conduit between the medication container 16 and the barrel 14. In the preferred embodiment, the through connector 30 has a tip 35 configured for puncturing the engaging end 20 of the medication container 16. Because the through connector 30 is enclosed completely by the plunger 12, a sharp instrument, such as a short needle or a sharp cannula, can be used without fear of a care provider coming into contact with the tip 35.

As an alternative, a blunt tube could press fit into the open neck of a medication container 16 whose frangible cover has been removed, or the through connector 30 could receive a mating connector on the medication container 16 to effect fluid communication as is known in the art. The through connector 30 is preferably made of metal, glass, rigid plastic, or any other material that will hold a sharp point and is rigid enough to puncture the medication container 16.

Referring now to FIG. 5, a groove 39 or standing rib formed on the through connector 30 can also be used to vent the medication container 16, if needed, such as when the present device 10 is used with a rigid container. Referring again to FIGs. 1 and 2, in the preferred embodiment, the through connector 30 is integral with the end of the plunger 12. More specifically, the through connector has relatively thickened walls which form an opening 36 defining a portion of the flow path of the liquid from the medication container 16.

In this embodiment, the tip 35 takes the form of a sharpened tubular needle which is inserted into the opening 36.

Referring now to FIG. 3, in an alternate embodiment, generally designated 10a, like features found in the syringe 10 are designated with like reference numbers. One difference between the syringe 10a and the syringe 10 is that the connector 30a is now provided as a separate piece which is inserted into the plunger 12 at the discharge end 13 and lodged therein by a sealed friction fit. The connector 30a has a tip 35a which is integrally formed with the connector. It is also contemplated that the connectors 30, 30a may be provided in other alternate configurations combining integrally formed and attached components. Referring again to FIGs. 1 and 2, once the engaging end 20 is punctured by the tip 35, the medication 22 flows through both the opening 36 in the through connector 30 and the check valve 32 before entering the barrel 14. The through connector 30 is thus in fluid communication with the container 16 and the medication 22 upon puncturing by the tip 35. Upon puncturing by the tip 35, the direction of flow of the medication 22 is controlled by the check valve 32. The check valve 32 is preferably an integral part of an annular wiping seal or piston 37. In the depicted embodiment, the check valve 32 is a slit type formed in the piston 37. The check valve 32 allows the medication 22 to flow from the medication container 16 and into the barrel 14, but closes to prevent backflow of the medication from the barrel back into the container 16.

Referring now to FIG. 3, a disk-type check valve 32a is disclosed which is disposed on the through connector 30a at the opposite end from the tip 35a. The disk-type check valve 32a may be tack welded at spaced points about its periphery to the through connector 30a. In this manner, liquid can flow from the container 16 towards the barrel 14 by going around the disk 32a in the areas not tack welded. However, liquid cannot flow backwards in this scenario because upon exposure to back flow, the disk collapses against the opening 36 to seal it.

In another variation of the check valve, the disk 32a freely floats between the through connector 30a and the discharge end 13 of the plunger 12. In this manner, liquid can flow past the disk 32a by pushing it away from the opening 36. Again, backflow into the opening 36 is prevented because any backflow will force the disk 32a against the opening, sealing it. To prevent the disk 32a from also sealing the opening 24, at least one and preferably two or three teats 33 are formed on the inside of the discharge end 13 to maintain the disk a spaced distance away from the opening 24. In this manner, the flow path from the medication container 16 is maintained in an open condition. Aside from the check valves disclosed above, duckbill-type valves or other known equivalent check valves are also contemplated. It is also contemplated that the check valve 32, 32a is provided as a separate component which is sealingly secured to the plunger 12 or anywhere in the fluid flow path of the through connector 30, 30a. This arrangement assures delivery of the complete dose of medication 22 that has been transferred into the barrel 14.

The plunger 12 is dimensioned to slidably fit inside the barrel 14 with the piston 37 securely disposed on an exterior of the plunger at the discharge end 13. Elastomeric or plastic materials may be used to form the seal 37. As an alternative, the function of the piston 37 can be incorporated into the design of the plunger 12. For example, concentric sealing rings could be molded onto the outer surface of the plunger near the discharge end 13.

Proper operation of the syringe 10 depends on being able to create a vacuum when the plunger 12 is pulled into the retracted position toward the loading end 26 of the barrel 14 to draw the medication 22 out of the medication container 16. That sealing relationship is partially created by the seal 37. Any type of conventional construction may be utilized, including O-rings, a fin or flap on the plunger 12 that wipes the surface of the barrel 14. Such seals 37 are well known in the syringe art.

An optional feature that can be designed into the piston 37 is a pressure control mechanism. This mechanism could be used to prevent catheter rupture or vein damage if excessive force is used to depress the plunger 12. In a preferred embodiment, the diameter of the piston 37 is dimensioned so that under specified normal or satisfactory pressures, the seal would be maintained. When a specified maximum pressure is exceeded, the fluid will leak around or through the piston 37, relieving the pressure, and providing the care provider with a visual indication of the excessive pressure, since liquid is leaking behind or backward of the piston into the plunger 12. Another method of reducing pressure is to design the piston 37 and the barrel 14 to be a larger than usual diameter. According to the formula: Pressure = Force/ Area, as the diameter increases, the same force exerted by the care provider will result in less pressure in the syringe 10. Pressure generated is inversely proportional to the diameter squared. A tip protector 38 is also needed at the discharge end 28 of the barrel

14 to create sufficient vacuum. Without the tip protector 38, ambient air will enter the barrel 14 when the plunger 12 is moved toward the loading end 26 of the barrel. It is necessary that the tip protector 38 form an airtight seal, provide a sterile barrier, and be removable. The tip protector 38 may be provided in a variety of configurations, as long as the discharge end 28 is releasably sealed off and, upon removal of the tip protector, can be re-opened for delivery of the medication 22. Preferred types of tip protectors 38 include the use of a tip protecting cap, a check valve, an adhesive seal or a break-away tab that can be snapped off after the barrel 12 is filled with medication 22, but before the plunger is moved toward the discharge end 28 of the barrel 14. By incorporating a oneway check valve into the tip protector 38, the syringe 10 could be loaded and primed without removing the seal. Use of a tip protecting cap or an adhesive seal as the tip protector 38 will have the additional advantage of maintaining sterility of the discharge end 28 of the barrel 14 until ready for use. It may also be desirable to tack weld the tip protector 38 in place to provide a tamper evident feature.

The shape of the barrel 14 defines the bore 34, which is the space within the barrel in which the plunger 12 moves. The plunger 12 and the barrel 14 must be shaped in a manner that allows the plunger 12 to be able to slidingly and reciprocally move within the bore 34 toward the loading end 26 or the discharge end 28 while keeping the piston 37 in position and maintaining the seal it creates. This requirement is preferably met by having the barrel 14 and the plunger 12 generally cylindrical in shape, with the plunger 12 having a smaller diameter than the barrel 14. However, the shapes are not limited to cylinders, and there is no reason why the plunger 12 and barrel 14 could not be generally rectangular, or formed in any other shape. Either or both the barrel 14 or the plunger 12 can optionally be marked with graduation marks to indicate the volume of the dosage. It is also preferred that the barrel 14 and the plunger 12 fit into standard syringe pumps. Before use, the entire interior of the syringe 10, 10a and all of its components, including the medication container and its contents must be sterilized. The medication container 16 can be filled with the medication 22 and sterilized before use using standard pharmaceutical manufacturing techniques. Blow, fill, seal technology is especially attractive because it uses a single inert polymeric material and is inexpensive. The medication container 16 may be sterile filled or terminally sterilized by a variety of methods. Sterilization of the medication container 16 and the liquid medication 22 can occur separately. The medication container 16 must then be filled with the medication 22 and sealed aseptically. As an alternative, the medication container 16 can be filled with medication 22 and sealed, then the sealed unit can be sterilized. The syringe 10, 10a must also be sterilized, and this can be done either before or after the medication container 16 is inserted into the plunger 12. Any known method of sterilization can be used that does not cause unacceptable physical deterioration to the medication container 16 or the medication 22 itself. It is anticipated that the medication container 16 can be inserted into a loading end 40 of the plunger 12 at any time before its use. Preferably, the loading end 40 is configured to receive containers 16 provided by a variety of pharmaceutical and medical supply sources. The syringes 10 can be shipped and stored empty and loaded with a medication container 16 only just prior to use. Pre-loaded syringes 10 can also be loaded with the medication container 16 at the manufacturer, then shipped and stored at the medical facility with the medication 22 in place and ready to use.

Rather than a preassembled configuration, the medication container 16 and syringe 10 could be supplied unassembled, either separately or packaged together in a kit. The care provider would aseptically load the medication container 16 into the empty plunger 12 at the time of use. Various ways are envisioned to insure that the loading is done aseptically. For example, an alcohol swab can be used to disinfect the end of the medication container 16 that engages the through connector 30. Alternatively, the medication container 16 can be manufactured with the tip protector 38, consisting of a peelable adhesive tab or a tip protecting cap. Once removed at the time of loading, a sterile engagement surface is exposed. Alternatively, the medication container 16 can be manufactured with sterile secondary packaging intended to maintain the exterior of the medication container 16 sterile during storage and to allow, at the time of loading, an aseptic transfer from the package into the barrel 14 without contaminating the engagement surface. This packaging may include a flexible blister or a rigid hard pack.

Yet another approach would be to design a medication container 16 with a frangible cover which, upon removal, exposes a sterile opening into the sterile interior. In this case, the exterior surface of the container does not have to be sterile and the container is actually open as it is being loaded into the barrel 14 and engaged with the through connector 30. The opening can be designed so that surface tension will prevent fluid from leaking out prior to engagement. Also, the exterior shape of the medication container 16, the opening and the barrel 14 can be designed to work together to prevent contamination of the opening prior to engagement. This differs from prior art ampules, which require precise manual alignment of a syringe tip into the sterile opening without the benefit of any alignment mechanisms. In the preferred embodiment, when the medication container 16 is pre-loaded into the plunger 12, an endcap 42 (best seen in FIG. 1) is preferably provided and is dimensioned to cover the loading end 40 of the plunger 12 and the loading end 26 of the barrel 14. The endcap 42 prevents premature puncturing and/or engagement of the medication container 16 with the through connector 30. In addition, the endcap 42 also maintains the cleanliness of the unit by covering the barrel 14 and plunger 12 such that contaminants cannot get inside. The end endcap 42 may be tack welded to the barrel 14 as a tamper evident feature.

Two different spaces must be protected from microbial contamination. The first is the annular space between the syringe barrel 14 and the plunger 12. The second is the annular space between the plunger 12 and the medication container 16. A single endcap 42 may be provided to protect both spaces, or separate caps may be provided to protect each space individually.

Referring now to FIGs. 2 and 3, the endcap 42 may be rigid or flexible. An advantage of a flexible endcap 42 (best seen in FIG. 3) is that the care provider can cause engagement of the medication container 16 upon the through connector tip 35, without having to open or remove the endcap. Although the embodiment of FIG. 3 is shown with both the membrane seal 41a and the flexible endcap 42, it will be understood that only one of such anti-contamination devices would be used at a time. If desired, a filter 44 may be included on the endcap 42 to provide a supply of sterile air. Where venting of the medication container 16 is necessary, such a sterile air vent provides additional protection against contamination, since only sterile air is drawn into the medication container. It is also contemplated that sterile air vents could be provided to other components of the syringe 10, 10a. However, it will be appreciated that the filtered endcap 42 must be secured on the loading end 40 of the plunger 12 to permit the plunger to be retracted, thus drawing in filtered air to provide the needed venting to the medication container 16. Aside from providing a flexible, filtered endcap, the space between the plunger 12 and the medication container 16 can also be protected with a plug. Preferably, the plug would be dimensioned to be press fit into the bore of the loading end 40. Another option is to provide the endcap 42 with a hinge attachment which is secured to either the barrel 14 or the plunger 12. By hinging the endcap 42, disposal of the syringe 10, 10a is simplified.

A sealing film can be used to cover the respective loading ends 26, 40 of the barrel 14 and the plunger 12. The film could either be removed or punched through when loading the medication container 16. Also, an elastomeric slit diaphragm can seal the loading ends 26, 40, yet allow the container 16 to be inserted into the loading end 40.

Referring again to FIG. 2, mixing of the medications 22 in situ can also be accomplished through the use of the present invention. A second medication 46, consisting of a powder or a liquid, can be pre-loaded in the barrel 14 of the syringe 10 by the manufacturer. The medication 22 would be contained between the tip protector 38 and the piston 37. In this embodiment, when the plunger 12 is retracted through the bore 34 of the barrel 14, the liquid medication 22 from the medication container 16 will be drawn into the bore 34. Turbulence from the flow of medication 22 into the bore 34 will cause mixing of the two substances 22, 46 in preparation for delivery. Manual shaking is also contemplated.

The medication 22 of the medication container 16 can be any medically useful liquid. For example, sterile saline could be used in the medication container 16 for mixing with the powdered medication 46 pre-loaded in the barrel 14 to effect the reconstitution of the powdered medication 46 or the dilution of a concentrated liquid medication 46. At the time of use, the care provider would transfer the medication 22 from the medication container 16 into the second medication 46 in the barrel 14, shake to mix the combined medications 22, 46, and deliver as previously described. Often, multiple medications must be given to a patient. Many of these drugs are unstable if stored together for long periods of time. However, many drug combinations are stable for short periods of time. These combinations would be suitable for the system described here where the second medication 46 is stored in the barrel 14 of the syringe 10, and the first medication 22 is stored in the medication container 16.

Referring now to FIG.4, an alternate embodiment of the syringe 10 is generally designated 50. Shared components of the syringes 10, 10a are designated with identical reference numerals. A main distinguishing feature of the syringe 50 is that a medication container 52 has been designed to also serve as the plunger. Accordingly, the container 52 will have a diameter which allows it to be slidingly reciprocated within the barrel 14. Naturally, it is contemplated that the barrel diameter may also be modified to provide this result. In addition, the container 52 will preferably be provided with a finger flange 31 to allow retraction of the container from the barrel 14 in the manner of the plunger 12.

At the engaging end 20 of the medication container 52, a securing formation is preferably provided to couple the medication container to the piston during the engagement step. In the embodiment depicted in FIG. 4, the securing formation takes the form of at least one preferably annular barb 54 on the tip 35. Another modification of the syringe 50 is that the piston 37 and the through connector 30 are provided as a separate component 56, made up of a piston 58 and a through connector 60, which is dimensioned to sealingly and wipingly engage the inside of the barrel 14.

Thus, upon engagement of the container 52 upon the tip 35 to establish the fluid communication described above, the barb 54 holds the container to the tip as the container is retracted, thus pulling the piston/connector 56 away from the discharge end 28. It is also contemplated that the securing formation 54 could be placed on the container 52 as well. Both the finger flange 31 and the securing formation 54 could easily be added to the blow molding process as the medication container 16 structure is formed.

Another preferred feature of the syringe 50, which might also be applied to the syringes 10, 10a, is that the medication container 52 may be provided with its own vent 62. Such a vent 62, contemplated as an air vent or a one-way check valve, facilitates flow of the medication 22 from the container 52 by allowing for the introduction of air into the container as the medication is removed under vacuum. In the preferred embodiment, the vent 62 is a one-way check valve, such as a slit diaphragm, a duckbill, or other one-way check valves known in the art.

The concept of a combined container/plunger would best be utilized where the medication container 16 comes pre-loaded in the syringe 10. When the unit is assembled by the user, sterile packaging would be required that enabled the combined sterile medication container 16 and plunger 12 to be loaded into the barrel 14 without contaminating the exterior surfaces of the medication container until engaged.

Referring now to FIGS. 6A-6E, the method of operation of the present syringe 10, 10a and 50 will be described. FIG. 6 A shows the syringe 10 pre-loaded with the medication container 16 and protected with the endcap 42. The first step is to remove the endcap 42. At this point, the medication container 16 is still intact and separates the medication 22 from the rest of the syringe 10. In FIG. 6B, the endcap 42 has been removed and the user has pushed the medication container 16 deep into the plunger 12 to engage the tip 35 of the through connector 30 to engage and puncture the medication container at the puncturable engaging end 20. This puts the medication 22 in fluid communication with the barrel 14 through the tip 35 of the through connector 30. It will be appreciated at this point that in the event the endcap 42 is provided of a flexible material, the care provider will not remove the endcap, but will press the medication container 16 upon the tip 35 to create the fluid communication. Referring now to FIG. 6C, the care provider next retracts the plunger 12, moving it toward the loading end 26 of the barrel 14, creating a vacuum in the bore 34 of the barrel. The vacuum, created by the piston 37 and the tip protector 38, draws the medication 22 from the medication container 16 into the flow path defined by the check valve 32a, the opening 36 in the through connector 30 and the bore 34 of the barrel 14, as depicted in FIG. 6C. The check valve 32a prevents the medication 22 from returning back into the container 16. This is best accomplished with the discharge end 28 of the barrel 14 oriented downward, as shown in FIG. 6C. FIG. 6D shows that the tip protector 38, in this case the tip protecting cap, has been removed. The syringe 10 has also been preferably rotated so that the discharge end 28 of the barrel 14 is oriented upward. Any air present in the barrel 14 may be primed out by depressing the plunger 12 slightly.

Referring now to FIG. 6E, after checking that the correct medication 22 and desired volume are present in the barrel 14, the plunger 12 is depressed in the usual manner, and the medication is forced through the opening 29 in the discharge end 28 of the barrel. The syringe 10 is then ready to be disposed of in the usual manner.

Another feature of the present invention is that a partial or full dose of the medication 22 may be withdrawn from the medication container 16, depending on the amount of plunger 12 retraction. In this scenario, only a portion of the medication 22 is transferred from the container 16 into the barrel. A partial dose can then be administered by full depression of the plunger 12. Successive partial doses may be administered by repeating the partial retraction of the plunger with the tip protector 38 in place (to withdraw a desired volume of medication from the container 16), and the full depression of the plunger 12, as described above.

Referring now to FIGs. 7A-7C, another alternate embodiment of the present syringe is generally designated 70. Components shared with prior embodiments are designated with identical reference numbers. The syringe 70 differs in one aspect from the prior embodiments in that several components have been eliminated, thus saving steps for the end user and eliminating complexity.

In one aspect, previously described embodiments required the user to push down on the fluid container or ampule 16 to activate a piercing of the fluid container. However, a feature of the syringe 70 is that it is designed to be pierced as it is primed, thus eliminating a step.

Another feature of the syringe 70 is that previously described embodiments required a negative pressure to be generated within the syringe component in order to draw solution out of the medication container. The syringe

70 expels solution into the barrel 14, eliminating the need for a negative pressure

(and for an airtight cap).

Still another feature of the syringe 70 is that previous embodiments required the syringe to be oriented in a particular direction in order to draw solution out with the previously mentioned negative pressure. The syringe 70 eliminates the need for this orientation by mechanically expelling the contents of the fluid container regardless of orientation.

Referring now to FIG. 7A, the syringe 70 includes a syringe barrel 72 with a small tab 74 on the loading end 26, a hollow plunger 76 with a longitudinal slot 78 extending down its side that will accommodate the tab 74 on the syringe barrel, and a medication container 80 preferably of the blow/fill/seal variety. In the present embodiment, the medication container 80 is provided with a baffled or accordion fold configuration, including a plurality of folds 82 which will facilitate its collapsing upon the exertion of an axial force thereon during operation of the syringe 70. An important aspect of the design of the container 80 is that the fluid container stays in a stable collapsed position after the fluid is expelled and does not revert back to its original position.

Another alternative way of getting a medication container 80 to stay in the collapsed position would be to provide a snap-fit between a top portion 84 and a bottom portion 86 of the container. As the container 80 collapses, one end portion would snap into the other, and the snap-fit would hold the container in the collapsed position.

Note that a rubber piston 37, 58 is not shown on these drawings, but it is contemplated that a piston could be added, depending on the application.

As provided, the entire interior of the assembled syringe 70 and medication container 80 is sterile, including the medication container and its contents. The medication container 80 can be filled and sterilized using standard pharmaceutical manufacturing techniques. Blow/fill/seal technology is especially attractive because it uses a single inert polymeric material and is inexpensive. The medication containers or ampules 80 may be sterile filled or terminally sterilized by a variety of methods. The other elements of the device 70 may also be sterilized by a variety of methods. The medication container 80 and the syringe 70 may be sterilized individually and aseptically assembled or they may be sterilized together after assembly.

The first step in the operation of the syringe 70 is to remove the device from any external packaging. At this point, the medication container 80 is still intact and separates the fluid contents from the rest of the device.

Referring now to FIG. 7B, an operator pulls back on the plunger 76. The tab 74 holds the fluid container 80 in place while the spike 35 on the plunger 76 pierces the container to provide a path into the barrel 72 or body of the syringe. Pulling back on the plunger 76 also collapses the folds 82 or bellows of the fluid container 80, expelling solution into the body of the syringe. Because the container 80 is stable in its collapsed position, the container stays collapsed. Referring now to FIG. 7C, the operator then verifies that the correct medication and desired volume is in the syringe barrel 72 and subsequently delivers it by depressing the plunger 76 in the usual manner. The device 70 is then ready to be disposed of in the usual manner. Referring now to FIGs. 8A-8C, the syringe 70 is shown provided with an alternate medication container 88. The container 88 is representative of a type of fluid container that collapses and remains in the collapsed position, and in the preferred embodiment is referred to as a bi-stable (football shaped) container. The syringe 70 works the same as described above in relation to FIGs. 7A-7C, but the container 88 will collapse in the radial direction or laterally as it is engaged by the tab 74, which facilitates evacuation of the medicinal contents of the container 88.

Referring now to FIGs. 9A-9D, another alternate embodiment of the present syringe is generally designated 90. Shared components with the previously described embodiments are designated with identical reference numbers. An important feature of the syringe 90 is that by changing the design of the fluid container and the plunger, the device can now be primed in the upright (nose up) position that most clinicians are familiar with. Previously described embodiments require the syringe to be oriented in a direction (the nose of the syringe pointing down) that clinicians were unaccustomed to in order to draw solution out with the negative pressure generated inside the syringe. The syringe 90 makes it possible to orient the nose of the syringe in the "nose up" direction that clinicians are familiar with. The syringe 90 includes an end cap 38, a syringe barrel 14, a hollow plunger 92, a piston 94 preferably with an integral one-way check valve, and a medication container 96 preferably of the blow/fill/seal variety. A main distinguishing feature of the syringe 90 is that the hollow plunger 92 is provided with an integral passageway 98 disposed along the wall of the plunger. In addition, a rear end of the passageway is formed into a sharp piercing point 100 for puncturing the medication container 96. Further, it will be seen that the medication container 96 is generally "T"-shaped when viewed from the front, so that one arm formation 102 of the container is engageable upon the point 100. It is also contemplated that the container may be provided with only a single arm 102 which is spiked by the point 100. The plunger has a recess 103 to receive the arms.

As described above in relation to the syringe 70 and the other embodiments, the entire interior of the assembly is sterile, including the medication container and its contents. The medication container can be filled and sterilized using standard pharmaceutical manufacturing techniques.

In operation, the device 90 is removed from any external packaging.

At this point, the medication container 96 is still intact and separates the fluid contents from the rest of the device 90. Referring now to FIG. 9B, the operator next depresses the medication container 96 into a bore or cavity 104 of the plunger 92, preferably using the thumb. This creates engagement between the plunger 92 and the fluid container 96 as the point 100 punctures the arm 102. This puts the contents of the fluid container 96 in communication with the syringe. Referring now to FIG. 9C, the operator then pulls back on the plunger 92 with its attached piston 94, creating a negative pressure differential in the syringe barrel 14. Fluid is drawn from the medication container 96 into the syringe barrel 14 via the passageway 98 in the hollow plunger and the one-way valve in the piston 94. The one-way valve prevents the return of the fluid back into the medication container 96. A partial or full dose may be withdrawn, depending on the amount of plunger retraction. This step is accomplished with the syringe tip oriented upward.

Referring now to FIG. 9D, the next step is to remove the tip cap 38 and prime out any air in the syringe 90 in the usual manner. After verifying that the correct medication and desired volume is in the syringe barrel 14, the dose can be delivered by depressing the plunger 92 in the usual manner. The device 90 is then ready to be disposed of in the usual manner.

Those skilled in the art will also recognize that many optional features, while not necessary to function, will make the syringe 10, 50, 70, 90 easier and more convenient to use. The barrel 14 and the plunger 12 can have finger flanges 31 to prevent the barrel from slipping while force is being applied to the plunger to move it within the bore 34. There are also a number of fittings or connectors, such as a luer coupling, that can be molded or added to the discharge end 28 of the barrel 14 to simplify connecting the discharge end to a hypodermic needle, an infusion catheter or other device for delivery of the medication 22. In many cases, the medication 22 can be administered through an intravenous line or an infusion catheter. This minimizes the need for hypodermic needles and the risks of improper disposal or of care providers being injured with a used needle. It is expected that these and other options will be used in connection with this invention.

While a particular embodiment of the syringe for transfer of medication from a pre-filled medication container has been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the claims recited below.

Claims

What is claimed is:

1. A liquid transfer device for use with a medication container used in the delivery of medication, comprising: a plunger having a discharge end, a loading end, an interior space configured for receiving the medication container, and a through connector for engaging a mating end of the medication container; said through connector member having an opening in fluid communication with the engaged medication container to define a flow path of the medication from the container, through the connector opening, into the plunger and out said discharge end; a check valve is provided in the flow path for preventing backflow of the medication; said plunger is configured such that when said medication container is engaged with said through connector, the medication flows from the medication container and into a barrel; said barrel defines a bore and has a discharge end, a loading end, and is dimensioned for slidably accommodating the plunger such that the plunger is movable therein between a depressed and a retracted position; a piston is disposed on an exterior of the plunger at the discharge end and configured to slidingly and sealingly engage said barrel; a tip protector is sealingly disposed at the discharge end of the barrel, such that when the plunger moves within the barrel toward the retracted position, a vacuum is created in the barrel; wherein upon the engagement of the medication container by the through connector, and the plunger being moved toward the retracted position with the tip protector in place, the medication is withdrawn from the medication container into the barrel, and when said protector is removed and the plunger is pushed toward the depressed position, the medication is propelled through the discharge end of the barrel.

2. The liquid transfer device of claim 1 wherein said tip protector is a tip protecting cap.

3. The liquid transfer device of claim 1 wherein said device is preassembled with a medication container inside said plunger.

4. The liquid transfer device of claim 3 wherein a wall of said medication container is rigid.

5. The liquid transfer device of claim 3 wherein said medication container is vented.

6. The liquid transfer device of claim 5 wherein said through connector vents said medication container.

7. The liquid transfer device of claim 3 wherein a wall of said medication container is collapsible.

8. The liquid transfer device of claim 3 wherein said barrel and said plunger are covered by a cap to provide a sterile seal for the interior of said plunger and said barrel, and to prevent the premature engagement of the medication container with said through connector.

9. The liquid transfer device of claim 1 wherein said barrel is pre-filled with a second liquid medication.

10. The liquid transfer device of claim 1 wherein said through connector has a sharpened tip and is secured within a discharge end of said plunger.

11. The liquid transfer device of claim 1 further including a pressure relief valve in said piston, said relief valve configured to allow liquid flow behind said piston when a specified pressure is exceeded in said syringe.

12. A combination liquid transfer device and medication container for use in the delivery of medication to a patient, comprising: a medication container having an engagement end and a finger flange at an opposite end; a through connector for engaging said engagement end of said medication container, and having a piston therein; said through connector having an opening in fluid communication with said engaged medication container to define a flow path of the medication from the container, through said connector opening, into said connector and out said discharge end; a check valve disposed in said flow path for preventing backflow of the medication; said through connector being configured such that when the medication container is engaged with the through connector, said medication flows from the medication container and into a barrel; said barrel defines a bore and has a discharge end, a loading end and is dimensioned for slidably accommodating said through connector and said medication container such that said connector and said container unit is movable therein between a depressed and a retracted position; said piston is configured for slidingly and sealingly engaging said barrel; a tip protector sealingly disposed at said discharge end of said barrel, such that when said connector and said container unit moves within said barrel toward said retracted position, a vacuum is created in said barrel; upon said engagement of said medication container by said through connector, and said connector and said container unit being moved toward said retracted position with said tip protector in place, said medication is withdrawn from said medication container into said barrel, and when said tip protector is removed and said connector and said container is pushed toward said depressed position, said medication is propelled through said discharge end of said barrel.

13. A combination liquid transfer device and medication container for use in the delivery of medication, comprising: a medication container filled with medication and having an engaging end; a plunger having a discharge end, a loading end, an interior space configured for receiving said medication container, and a through connector for engaging a mating end of said medication container; said through connector having an opening in fluid communication with said engaged medication container to define a flow path of the medication from said container, through said connector opening, into said plunger and out said discharge end; a check valve in said flow path for preventing backflow of said medication; said plunger being configured such that when said medication container is punctured and engaged with said through connector, the medication flows from said medication container and into a barrel; said barrel defining a bore and having a discharge end, a loading end, being dimensioned for slidably accommodating said plunger such that said plunger is movable therein between a depressed and a retracted position; a piston on an exterior of said plunger at said discharge end is configured to slidingly and sealingly engage said baπel; wherein upon the puncturing of said medication container by said through connector, and said plunger being moved toward said retracted position, the medication is withdrawn from said medication container into said baπel, and when said plug seal is removed and said plunger is pushed toward the depressed position, the medication is propelled through said discharge end of said baπel.

14. The combination of claim 13 further including a tip protector sealingly disposed at said discharge end of said baπel, such that when said plunger moves within said baπel toward said retracted position, a vacuum is created in said baπel to facilitate withdrawal of the medication from the container and into said baπel.

15. The combination of claim 14 wherein said plunger is provided with an integral passageway having a piercing point located at a rear end and adjacent a loading end of said plunger.

16. The combination of claim 15 wherein said medication container is configured with a portion disposed to be punctured by said piercing point.

17. The combination of claim 13 further including a tab disposed on said baπel adjacent said loading end for engaging said medication container and stabilizing said container within said baπel.

18. The combination of claim 17 further including a longitudinal slot in said plunger configured for accommodating said tab and permitting sliding movement of said plunger relative to said baπel.

19. The combination of claim 17 wherein said medication container is provided with a baffled configuration for accommodating axial compression.

20. The combination of claim 17 wherein said medication container is provided with a bi-stable configuration.

21. A method for transferring medication from a medication container, comprising: inserting a medication container into a plunger defining a space configured for receiving the medication container, said plunger having a through connector for engaging an end of the medication container, said through connector having an opening in fluid communication with said medication container, said opening having a one-way valve preventing backflow of the medication into the medication container; providing a baπel defining a bore dimensioned for slidably accommodating said plunger and having a discharge end and a loading end, said discharge end having a tip protector sealingly engaged thereon; depressing the medication container into puncturing engagement with said through connector so that the medication is permitted to flow through said through connector and into said baπel; moving said plunger toward said loading end of said baπel such that a vacuum is created which draws the medication from the medication container, through said through connector and said one-way valve and into said baπel; removing said tip protector from said discharge end of said baπel; and moving the plunger toward said discharge end of said baπel, increasing the pressure in the bore such that the medication is propelled from said discharge end.

22. The method of claim 21 further including sterilizing said plunger, said through connector, said baπel and said tip protector before the medication container is inserted into said plunger.

23. The method of claim 21 further including sterilizing said plunger, said through connector, said baπel and said tip protector after the sealed medication container is inserted into said plunger.

24. The method of claim 21 further including prefilling said baπel with at least one of a second liquid medication and a powdered medication for mixing with said liquid medication in the medication container upon the passage of the liquid medication through said one-way valve.

25. The method of claim 21 further including preassembling said plunger with the medication container inserted therein.

26. The method of claim 21 further including placing a cap over said loading end of said baπel such that the medication container is not prematurely punctured by said through connector.

27. The method of claim 21 further including inserting the medication container into said plunger at the time of use.

28. The method of claim 21 further including transferring only portions of the medication container into said syringe and administering the portions by fully depressing the plunger.

29. The method of claim 28 further including providing repeat partial doses as described above until said medication in said medication container is used up.