Plunger Covers and Plungers for Use in Syringes and Methods of Fabricating Plunger Covers and Plungers for Use in Syringes

• US 20070219508A1
• Filed: 03/14/2007
• Published: 09/20/2007
• Est. Priority Date: 03/15/2006
• Status: Active Grant

• Current Assignee: Bayer Healthcare LLC (Bayer AG)
• Original Assignee: Medrad Incorporated (Bayer AG)
• Inventors: Bisegna, Joseph E., Neff, Jared
• Granted Patent: US 8,926,569 B2
• Time in Patent Office: Days
• US Class Current: 604/218
• CPC Class Codes: A61M 5/31513 Piston constructions to improve sealing or sliding
• CPC Class Codes: A61M 5/31515 Connection of piston with piston rod

Abstract

A plunger cover for use with a syringe includes a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe. The central portion can, for example, be more rigid than the sealing portion. The sealing portion and the central portion are connected in an overmolding process. The sealing portion can, for example, be formed from a thermoplastic elastomer or a thermoplastic polyurethane. The central portion can, for example, be formed from polypropylene, acrylonitrile butadiene styrene, polycarbonate or copolymers thereof.

Claims

1. A plunger cover for use with a syringe comprising a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process.

2. The plunger cover of claim 1 wherein the sealing portion is formed from a thermoplastic elastomer or a thermoplastic polyurethane.

3. The plunger cover of claim 1 wherein the central portion is formed from polypropylene, acrylonitrile butadiene styrene or polycarbonate.

4. The plunger cover of claim 1 wherein the sealing portion is injection molded first and the central portion is injection overmolded thereon.

5. The plunger cover of claim 4 wherein the material for the sealing portion and the material for the central portion are selected so that molecular bonding occurs between the sealing portion and the central portion.

6. The plunger cover of claim 1 wherein the central portion is injection molded first and the sealing portion is injection overmolded thereon.

7. The plunger cover of claim 6 wherein the material for the central portion and the material for the sealing portion are selected so that molecular bonding occurs between the central portion and the sealing portion.

8. A plunger for use with a syringe comprising:

a plunger cover comprising a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process, the plunger further comprising a support attached to the plunger cover.

9. The plunger of claim 8 wherein the sealing portion is formed from a thermoplastic elastomer or a thermoplastic polyurethane.

10. The plunger of claim 8 wherein the central portion is formed from polypropylene, acrylonitrile butadiene styrene or polycarbonate.

11. The plunger of claim 8 wherein the sealing portion is injection molded first and the conical portion is injection overmolded thereon.

12. The plunger of claim 11 wherein the material for the sealing portion and the material for the central portion are selected so that molecular bonding occurs between the sealing portion and the central portion.

13. The plunger of claim 8 wherein the central portion is injection molded first and the sealing portion is injection overmolded thereon.

14. The plunger of claim 13 wherein the material for the central portion and the material for the sealing portion are selected so that molecular bonding occurs between the central portion and the sealing portion.

15. The plunger of claim 8 wherein the sealing portion includes a radially inward projecting flange that is seated within a seating formed on the support to connect the plunger cover to the support.

16. The plunger of claim 8 wherein the support includes a forward surface adapted to abut the plunger cover to prevent rearward motion of the central portion relative to the support.

20. The method of claim 16 wherein the central portion is injection molded first and the sealing portion is injection overmolded thereon.

17. A syringe comprising:

a syringe body and a plunger slidably positioned within the syringe body, the plunger comprising a plunger cover comprising a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process, the plunger further comprising a support attached to the plunger cover.

18. A method of fabricating a plunger cover for use in a syringe, comprising:

connecting a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe in an overmolding process, the central portion being more rigid than the sealing portion.

19. The method of claim 18 wherein the sealing portion is injection molded first and the central portion is injection overmolded thereon.

21. A plunger cover for use with a syringe comprising a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe, the central portion having at least one physiochemical property that differs from the sealing portion, the sealing portion and the central portion being connected in an overmolding process.

22. A plunger cover for use with a syringe comprising a sealing portion adapted to form a seal with the syringe and a central portion, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process.

23. The plunger cover of claim 22 wherein the central portion is positioned forward of at least a portion of the sealing portion and is adapted to contact fluid within the syringe.

24. The plunger cover of claim 23 wherein the central portion is overmolded upon the sealing portion.

25. The plunger cover of claim 22 wherein the central portion is positioned rearward of a generally central section of the sealing portion and does not contact fluid within the syringe.

26. The plunger cover of claim 24 wherein the central portion is overmolded upon the sealing portion.

27. A plunger for use with a syringe comprising:

a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process.

28. The plunger of claim 27 wherein the sealing portion is adapted to form an operative connection with a drive member.