Gasket for prefilled syringe

Patent metadata

Field	Value
Publication number	US-2016101239-A1
Application number	US-201514879721-A
Country	US
Kind code	A1
Filing date	Oct 9, 2015
Priority date	Oct 10, 2014
Publication date	Apr 14, 2016
Grant date	—

Abstract

A gasket ( 10 ) for a prefilled syringe is provided, which has a generally cylindrical outer shape, and includes a liquid contact portion ( 13 ) provided on one of opposite end faces, a thread hole ( 15 ) provided in the other end face for attachment of a plunger, and at least two annular projections ( 17 A, 17 B) provided on a peripheral surface ( 16 ) and spaced from each other by an annular trough ( 18 ) in a gasket height direction (gasket axial direction) extending from the one end face to the other end face, wherein a diameter difference (A) (=a 1 −a 2 ) between a diameter (a 1 ) of the annular projections ( 17 A, 17 B) and a diameter (a 2 ) of the annular trough and a diameter difference (B) (=b 1 −b 2 ) between a thread root diameter (b 1 ) and a thread ridge diameter (b 2 ) of an internal thread portion of the thread hole satisfy a ratio relationship of A:B=1:(2 to 4).

First claim

What is claimed is:

1 . A gasket for a prefilled syringe, the gasket comprising:
a generally cylindrical main body having a liquid contact portion provided on one of opposite end faces thereof, and a thread hole provided in the other end face thereof for attachment of a plunger; and at least two annular projections provided on a peripheral surface of the main body and spaced from each other by an annular trough in a gasket height direction (gasket axial direction) extending from the one end face to the other end face; wherein a diameter difference A (=a 1 −a 2 ) between a diameter a 1 of the annular projections and a diameter a 2 of the annular trough and a diameter difference B (=b 1 −b 2 ) between a thread root diameter b 1 and a thread ridge diameter b 2 of an internal thread portion of the thread hole satisfy a ratio relationship of A:B=1:(2 to 4).

2 . The gasket according to claim 1 , wherein at least the liquid contact portion and the annular projections are covered with an inert film.

3 . The gasket according to claim 2 , wherein the inert film is made of a material comprising at least one of PTEF, ETEF, PFA, FEP, PCTFE, PVDF and PVF, modified fluororesins obtained by modifying these resins, nylons and ultrahigh molecular weight PE.

4 . The gasket according to claim 1 , wherein the annular projections provided on the peripheral surface have a total width that is 20 to 70% of a height of the gasket as measured axially of the gasket.

5 . The gasket according to claim 1 , wherein the internal thread portion of the thread hole has 1 to 3.5 thread turns.

Assignees

• Sumitomo Rubber Ind

Inventors

• Ishida Naoyuki
• Nakano Hiroaki
• Matsutani Yuichiro
• Kaneko Hiroyuki

Classifications

• A61M2205/0222

  Materials for reducing friction · CPC title

• A61M2205/19

  Constructional features of carpules, syringes or blisters · CPC title

• A61M5/31513 Primary

  Piston constructions to improve sealing or sliding · CPC title

• B29C43/021

  characterised by the shape of the surface · CPC title

• A61M2205/0238

  the material being a coating or protective layer · CPC title