MEDICAMENT CARTRIDGE

Abstract: The present invention discloses a medicament cartridge (10) for an injection device, such as a syringe or a jet injector. The medicament cartridge (10) according to the present invention includes a tubular member (12) having a lumen (18), a needle (20) operatively associated with an end of the tubular member (12) and having a piercing end (22) extending into the lumen (18), a first stopper (28) located within the lumen near the other end of the tubular member (12) and slidable within the lumen (18), and a flexible member (26) located within the lumen (18) and covering the piercing end (22) of the needle (20). Examples of suitable flexible members include a flexible membrane (26), a cap (46) having a base (48) with a collapsible portion (50), and the like. The compression of the medicament flexes the flexible member (26) into contact with the piercing end (22) of the needle (20) so that the piercing end pierces the flexible member (26) to thereby create a fluid pathway for the medicament through the needle (20).

Description: MEDICAMENT CARTRIDGE Field of the Invention The present invention is directed to a device for delivery of medicament, and in particular to a medicament cartridge for use with a medicament injector, such as a syringe or needle assisted jet injector. Background of the Invention Medicament cartridge having three stoppers are useful for a number of applications, including separation of the needle from a colloid or particulate drug until injection to prevent needle clogging. Three stopper designs can be used in any situation in which there is reason not to have the needle bearing stopper in contact with the drug prior to the injection. This could be required for drug stability reasons - either because the drug was inherently unstable or because stability data existed for the drug but without a needle. In prior three stopper designs, a first stopper is located at one end of the medicament cartridge with an end of the needle protruding from both sides of the stopper. The second stopper is located at the other end of the medicament cartridge and the third stopper is located between the first and second stoppers, with the medicament filling the space between the second and third stoppers. Upon activation of the injector, an energy mechanism urges the second stopper toward the first stopper. This movement results in the creation of fluid pressure due to incompressibility of the medicament. This fluid pressure forces the third stopper toward the first stopper causing the needle end to puncture the third stopper, thereby creating a fluid pathway for the medicament. An inherent challenge to the three stopper design is the complexity added to the manufacturing process, and in particular, to aseptically filling the medicament cartridge. The requirement for placing all three stoppers in specific locations will add both handling complexity and costs to the process. A major concern associated with handling complexity associated with aseptic filling is that every manipulation step is a potential for introducing contamination. Having a significant amount of failure due to contamination represents a large health and economic risk to the filler. An additional complication to three stopper designs in which one stopper contains a double ended needle is the handling of the needle-stopper combination after it is manufactured. In some commercially available designs, the designs anticipate sterilization after manufacture followed by shipment in appropriate containers to the filling facility. Packaging of such an article with two sharp needle ends is complicated. The needle points have to be preserved in their manufactured form to be functionally optimal. Also, the handling of such needles by manual assembly processes or by automated processes requires packaging to allow safe shipment and handling. This adds complexity and cost to the piece in addition to adding the complexity of requiring the packaging to be removed as part of the final device assembly process. Thus, there exists a need for an improved three stopper medicament cartridge. Summary of Invention The present invention relates to a medicament cartridge for an injection device for delivering a medicament. The medicament cartridge according to the present invention comprises a tubular member having first and second ends and a lumen with a longitudinal axis for retaining the medicament therein, a needle operatively associated with the second end of the tubular member and having a piercing end, a first stopper located within the lumen near the first end of the tubular member and moveable within the lumen along the longitudinal axis, and a flexible member located within the lumen near the second end of the tubular member and covering the piercing end of the needle. Relative movement between the first stopper and the flexible member compresses the medicament and urges the flexible member toward the second end of the tubular member such that the piercing end of the needle pierces the flexible member to create a fluid pathway for the medicament through the needle. In one embodiment, the relative movement between the first stopper and the flexible member results from the first stopper moving toward the second end of the tubular member to compress the medicament. The needle is located in a second stopper with the piercing end extending from the second stopper and at least a portion of the second stopper inserted in the lumen near the second end of the tubular member. The piercing end of the needle can be beveled to facilitate puncturing the flexible member. In an exemplary embodiment, the flexible member is a flexible membrane attached to the second stopper with at least a portion of the flexible membrane located between the second stopper and the tubular member. The second stopper can include a first section with a wall defining a cavity having an opening and the first stopper has a medicament contacting surface configured and dimensioned to mate with the opening of the cavity to minimize volume of medicament remaining in the lumen after the first stopper has reached the second end of the tubular member. The shape of the cavity can be frustroconical or any other suitable configuration. The second stopper can also include a second section extending beyond the tubular member and a shoulder located between the first and second sections of the second stopper and contacting the second end of the tubular member. The needle can have an injecting tip opposite the piercing end and the medicament cartridge can include a needle guard covering this injecting tip. To facilitate handling during assembly, the needle guard has an enlarged end larger than the opening of the cavity of the second stopper or the needle guard is configured and dimensioned to be insertable in the opening without contacting the needle. In another embodiment, the flexible member comprises a cap and a base with a collapsible portion that flexes upon compression of the flexible member. The first stopper has a medicament contacting surface and the cap has a surface with a dimple configured and dimensioned to mate with at least a portion of the medicament contacting surface to minimize volume of medicament remaining in the lumen after the first stopper has reached the second end of the tubular member. The piercing end of the needle pierces the dimpled surface of the cap. Brief Description of the Drawings Preferred features of the present invention are disclosed in the accompanying drawings, wherein similar reference characters denote similar elements throughout the several views and wherein: Figure 1 is a cross sectional view of an embodiment of the medicament cartridge according to the present invention; Figure 2 is a cross sectional view of the medicament cartridge of Figure 1 upon activation of an energy mechanism to commence an injection; Figure 3 is a cross sectional view of the medicament cartridge of Figure 1 near completion of the injection; Figure 4 is a cross section view of a portion of the medicament cartridge of Figure 1 prior to completion of assembly (e.g. without a flexible member covering the needle) and fill; Figure 5 is a cross sectional view of another embodiment of the medicament cartridge according to the present invention; Figure 6 is a cross sectional view of the medicament cartridge of Figure 5 upon activation of an energy mechanism to commence an injection; and Figure 7 is a cross sectional view of the medicament cartridge of Figure 5 near completion of the injection. - 3 Description of the Preferred Embodiments As shown in Figure 1, a medicament cartridge 10 according to the present invention comprises a tubular member 12 having a distal or first end 14 and a proximal or second end 16. The terms proximal and distal are used with respect to the injection site so that distal or first end 14 is the end of tubular member 12 farthest from the injection site and the proximal or second end 16 is nearest to the injection site. Tubular member 12 defines a lumen 18 that has a cylindrical shape with a longitudinal axis. When cartridge 10 is filled with medicament, lumen 18 will be in contact with the medicament. Therefore, tubular member 12 should be made of a material compatible with the medicament. Alternatively, the walls of lumen 18 could be coated with such a material. An example of a material known to be compatible with most medicaments is borosilicate glass and other examples of suitable materials are well known to those of ordinary skill in the art. A needle 20 is operatively associated with second end 16 of tubular member 12. Needle 20 has a piercing end 22 that extends into lumen 18 and, in an exemplary embodiment, an injecting tip 24 extending beyond second end 16 of tubular member 12 and inserted into the person receiving the injection. The length of injecting tip 24 can be selected based on the injection device and particular application that cartridge 10 is intended for use with. For example, if the injection device is a conventional auto-injector, the length of injecting tip 24 should be at least about 5 mm. If the injection device is a needle-assisted jet injector, the length of injecting tip 24 is about 5 mm or less. If the injection device is a jet injector, then injecting tip 24 does not extend substantially beyond second end 16. As is the case with most injection devices and medicament cartridge, a sheath or needle cap 25 (shown in Figure 4) typically covers injecting tip 24 to keep it clean and free from debris. Prior to use, the sheath is removed. Cartridge 10 also has a flexible member, a flexible membrane 26, that covers piercing end 22 of needle 20. When cartridge 10 is assembled and filled, membrane 26 is located within lumen 18 near second end 16 of tubular member 12. The medicament in lumen 18 is located between membrane 26 and a first stopper 28, which is near first end 14 of tubular member 12. As membrane 26 covers piercing end 22 of needle 20, membrane 26 prevents contact between the medicament and needle 20 until use. Membrane 26 also protects piercing end 22 against contamination during manufacturing and fill of cartridge 10. In an exemplary embodiment, needle 20 is located in a second stopper 30 with piercing end 22 extending from second stopper 30 and at least a portion of the second stopper 30 inserted in lumen 18 near second end 16 of tubular member 12. Injecting tip 24 extends beyond second end 16 of tubular member 12. Second stopper 30 comprises a first section 32 with a wall 34 defining a cavity 36. Cavity 36 is shown having a frustroconical shape, although other shapes are envisioned within the scope of the current invention. Piercing end 22 of needle 20 extends into cavity 36. As described in more detail below, the sliding of first stopper 28 in lumen 18 toward second end 16 of tubular member 12 expels medicament from lumen 18 through needle 20, i.e. injection of the medicament. In order to minimize the volume of medicament remaining in lumen 18 after the injection is complete, first stopper 28 has a medicament contacting surface 38 that mates with cavity 36 as best seen in FIG. 3. Second stopper 30 also has a second section 40 that extends beyond tubular member 12. A shoulder 42 contacts second end 16 of tubular member 12 and is located between first and second sections 32, 40 of second stopper 30. In order to ensure that piercing end 22 is covered by flexible member 26 during manufacturing and fill, membrane 26 can be attached or otherwise affixed to second stopper 30 either before needle 20 is inserted into second stopper 30 or shortly thereafter. Once assembled, at least a portion of membrane 26 is located between first section 32 of second stopper 30 and tubular member 12. As previously noted, membrane 26 prevents contact between the medicament and needle 20 until use and protects piercing end 22 against contamination during manufacturing and fill of cartridge 10. Additionally and as best seen in Figure 4, needle cap 25 is configured and dimensioned so that even prior to placement of flexible membrane 26 to cover piercing end 22, there is no risk of contact with piercing end 22. Specifically, needle cap 25 has an enlarged end 44 that has a width or diameter (w) that is larger than the width or diameter (o) of cavity 36 shielding piercing end 22 of needle 20. Furthermore, the depth (d) that needle 20 is recessed in cavity 36 is chosen so that enlarged end 42 cannot contact any part of needle 20. The other dimensions of cartridge 10 have also been selected such that protruding features cannot extend deep enough into cavity 36 to damage or impinge piercing end 22. In particular, the width and length of wall 34 and shoulder 42 are selected such that neither wall 34 or shoulder 42 can extend into cavity 36 to come in contact with any part of needle 20. The operation of medicament cartridge 10 will now be described. Prior to use, first stopper 28 is located in lumen 18 near first end 14 of tubular member 12. The medicament is contained in lumen 18 of tubular member 12. The boundaries of the medicament are defined by tubular member 12 in the longitudinal axis and first stopper 28 at first end 14 and membrane 26 at second end 16. The portion of membrane 26 covering piercing end 22 of needle 20 has a dome-like shape. Upon movement of first stopper 28, which can occur by activation or firing of an injection device (not shown) to commence an injection, a force acts on first stopper 28 to urge first stopper 28 toward second end 16 of tubular member 12. The movement of first stopper 28 toward second end 16 causes compression of the medicament in lumen 18 between first stopper 28 and membrane 26. Medicament cartridge 10 is contained in an injection device (not shown) so that second stopper 30 at second end 16 cannot be pushed away from medicament cartridge 10. Shoulder 42, which contacts second end 16 of tubular member 12 when anchored in the injection device, prevents second stopper 30 from detaching from tubular member 12 as the result of the movement of first stopper 28. As the medicament is incompressible to at least some degree, the compression of the medicament causes membrane 26 to flex toward second end 16 of tubular member 12. This flexing of membrane 26 brings membrane 26 into contact with piercing end 22 of needle 20. Piercing end 22 of needle 20 pierces membrane 26 to create a fluid pathway for the medicament. The injection continues as first stopper 28 continues to slide within lumen 18 until surface 38 of first stopper 28 contacts second stopper 30. The present invention encompasses any manner of causing compression of the medicament. Relative movement between first and second stoppers 28, 30 would result in compression of the medicament. Compression could be caused, for example, by movement of second stopper 28 toward first end 14 of tubular member 12. One mechanism that could cause this movement is twisting or pushing second stopper 30 toward first stopper 28 to further "seat" second stopper 30. Figures 5-7 show another embodiment of a medicament cartridge according to the present invention in which the flexible member is a cap 46 with a base 48 extending therefrom. Base 48 has a collapsible portion 50 that flexes upon application of a pressure. In particular, the compression of medicament in lumen 18 between first stopper 28 and cap 46 (in response to movement of first stopper 28 toward second end 16 of tubular member 12 upon activation or injection device firing) causes collapsible portion 50 to flex sufficiently so that piercing end 22 of needle 20 pierces cap 46 to create a fluid pathway for the medicament through needle 20. Cap 46 has a dimple 52 that mates with medicament contacting surface 38 of first stopper 28 to minimize volume of medicament remaining in lumen 18 after completion of the injection. Dimple 52 also reduces the cross section of cap 46 that must be pierced by piercing end 22. A number of materials, including polymers and elastomers, can be used for the flexible member (membrane 26 or cap 46 and base 48) as long as: (1) the flexible member can be punctured by piercing end 22; (2) the flexible member has the desired flexibility; (3) the flexible member is compatible with the medicament; and (4) possesses the appropriate barrier properties required for a drug container. Although piercing end 22 of needle 20 is shown having a beveled end, any geometry capable of piercing membrane 26 can be used.

Claims: While it is apparent that the illustrative embodiments of the invention herein disclosed fulfil the objectives stated above, it will be appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments which come within the spirit and scope of the present invention. - 7 THE CLAIMS What is claimed is: 1. A medicament cartridge for an injection device for delivering a medicament, the medicament cartridge comprising: a tubular member having first and second ends and a lumen with a longitudinal axis for retaining the medicament therein; a needle operatively associated with the second end of the tubular member and o having a piercing end; a first stopper located within the lumen near the first end of the tubular member and moveable within the lumen along the longitudinal axis; and a flexible member located within the lumen near the second end of the tubular member and covering the piercing end of the needle, 5 wherein relative movement between the first stopper and the flexible member compresses the medicament and urges the flexible member toward the second end of the tubular member such that the piercing end of the needle pierces the flexible member to create a fluid pathway for the medicament through the needle. 0 2. The medicament cartridge of claim 1 wherein the piercing end of the needle has a bevel. 3. The medicament cartridge of claim 1 wherein the first stopper moves toward the second end of the tubular member to compress the medicament. 5 4. The medicament cartridge of claim 3 wherein the needle is located in a second stopper with the piercing end extending from the second stopper and at least a portion of the second stopper inserted in the lumen near the second end of the tubular member. 0 5. The medicament cartridge of claim 4 wherein the flexible member is a flexible membrane. 6. The medicament cartridge of claim 5 wherein at least a portion of the flexible membrane is located between the second stopper and the tubular member. 5 7. The medicament cartridge of claim 5 wherein the flexible membrane is attached to the second stopper. 8. The medicament cartridge of claim 4 wherein the second stopper comprises a first section with a wall defining a cavity and wherein the piercing end of the needle extends into the cavity. 9. The medicament cartridge of claim 8 wherein the cavity has a frustroconical shape. 10 10. The medicament cartridge of claim 9 wherein the first stopper has a medicament contacting surface configured and dimensioned to mate with the frustroconical shape of the cavity to minimize volume of medicament remaining in the lumen after the first stopper has reached the second end of the tubular member. 15 11. The medicament cartridge of claim 8 wherein the needle has an injecting tip extending beyond the second end of the tubular member and the medicament cartridge further comprises a needle guard covering the injecting tip. 12. The medicament cartridge of claim 11 wherein the cavity has an opening and the 20 piercing end is recessed from the opening. 13. The medicament cartridge of claim 12 wherein the needle guard has an enlarged end larger than the opening of the cavity. 25 14. The medicament cartridge of claim 12 wherein the needle guard is configured and dimensioned to be insertable in the opening without contacting the needle. 15. The medicament cartridge of claim 8 wherein the second stopper further comprises a second section extending beyond the tubular member and a shoulder located between the 30 first and second sections of the second stopper and contacting the second end of the tubular member. 16. The medicament cartridge of claim 4 wherein the second stopper comprises a first section with a wall defining a cavity having an opening and the first stopper has a 35 medicament contacting surface configured and dimensioned to mate with the opening of the

Inventors: LESCH PAUL R JR, SADOWSKI PETER L, LESCH, PAUL, R., JR., SADOWSKI, PETER, L.
Applicants: MEDI JECT CORP, MEDI-JECT CORPORATION
Application year: 2000
Main classification: A61M5
IPC codes: A61M5