Piston for a syringe and a prefilled syringe using the same

• US 7,927,315 B2
• Filed: 09/23/2004
• Issued: 04/19/2011
• Est. Priority Date: 12/17/2003
• Status: Expired due to Fees

• Current Assignee: Daikyo Seiko, Ltd.
• Original Assignee: Daikyo Seiko, Ltd.
• Inventors: Sudo, Masamichi, Sudo, Morihiro
• Primary Examiner(s): Sirmons; Kevin C.
• Assistant Examiner(s): Anderson; Michael J
• Application Number:
  US10/947,258
• Publication Number:
  US 20050137533A1
• Time in Patent Office: 2,399 Days
• Field of Search: 604/218, 604/187, 604/230, 604/110, 604/222, 604/15, 604/18, 604/38
• US Class Current: 604/218
• CPC Class Codes: A61M 2205/0222 Materials for reducing friction
• CPC Class Codes: A61M 2205/0238 the material being a coating or protective layer
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/31513 Piston constructions to improve sealing or sliding
• CPC Class Codes: A61M 5/5013 Means for blocking the piston or the fluid passageway to prevent illegal refilling of a syringe
• CPC Class Codes: A61M 5/502 for blocking the piston

Abstract

A sealing stopper or piston for a syringe which includes a skirt part that is capable of serving as a backstop device, and a prefilled syringe using the same. The skirt part provides a backstop function, i.e. it prevents reverse movement of the piston, without increasing production costs.

Claims

1. A piston for sealing an injection barrel of a syringe filled with medicament, said piston comprising a skirt part shaped and arranged so as to contact an inner wall of the injection barrel to allow motion of said piston in a direction along a longitudinal axis of the injection barrel, and to restrict movement of said piston in an opposite direction along the longitudinal axis of the injection barrel.

2. The piston as claimed in claim 1, wherein:

said piston is subjected to film lamination and/or lubricant coating;

said skirt part has a rubber exposed surface for contacting the injection barrel;

at least a part of said skirt part is inside a maximum outer diameter of said piston; and

said skirt part has an outer diameter which is greater than an inner diameter of the injection barrel.

3. The piston as claimed in claim 1, wherein an angle of said skirt part is in a range of 30 to 80°

measured from a surface that is perpendicular to a direction in which said piston is slidably moved in the injection barrel.

4. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as claimed in claim 1.

5. The piston as claimed in claim 2, wherein an angle of the skirt part is in a range of 30 to 80°

based on a standard surface perpendicular to such a direction that the piston is slidably moved in the injection barrel.

6. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as claimed in claim 2.

7. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as claimed in claim 3.

8. A piston for sealing an injection barrel of a syringe filled with medicament, said piston comprising:

a piston body; and

a skirt part extending outwardly from said piston body to contact the injection barrel;

wherein said skirt part is shaped and arranged so as to allow movement of said piston in a direction along a longitudinal axis of the injection barrel, and to effectively prevent movement of said piston in an opposite direction along the longitudinal axis of the injection barrel.

9. The piston as claimed in claim 8, further comprising an outer layer covering a portion of said piston body.

10. The piston as claimed in claim 9, wherein said outer layer comprises a film laminate and/or a lubrication coating.

11. The piston as claimed in claim 8, wherein said piston body comprises rubber, thermoplastic elastomer, or plastic material.

12. The piston as claimed in claim 8, wherein said skirt part extends from said piston body at an angle that ranges from 30 degrees to 80 degrees with respect to a longitudinal axis of said piston body.

13. The piston as claimed in claim 8

wherein said skirt part has an exposed rubber surface for contacting the injection barrel;

wherein at least a part of said skirt part is inside a maximum outer diameter of said piston; and

wherein said skirt part has an outer diameter which is greater than an inner diameter of the injection barrel.

14. The piston as in claim 13, further comprising an outer layer covering a portion of said piston body;

wherein said outer layer comprises a film laminate and/or a lubrication coating;

wherein said piston body is formed of rubber, thermoplastic elastomer, or plastic material;

wherein said skirt part extends from said piston body at an angle that ranges from 30 degrees to 80 degrees with respect to a longitudinal axis of the piston body;

wherein at least a part of said skirt part is inside a maximum outer diameter of said piston; and

wherein said skirt part has an outer diameter which is greater than an inner diameter of the injection barrel.

15. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as in claim 8.

16. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as in claim 9.

17. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as in claim 10.

18. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as in claim 12.

19. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as in claim 13.

20. A prefilled syringe comprising an injection barrel filled with medicament, and sealed by a piston as in claim 14.