Mold for gasket for prefilled syringe

Abstract

The present invention aims to provide a gasket for a pre-filled syringe which has excellent air-tightness and liquid-tightness and a mold for forming the gasket. The present invention relate to a mold for a gasket laminated with an inactive film for a pre-filled syringe, wherein at least a surface of the mold which forms a seal sliding surface of an annular protrusion of the gasket is mirror finished to have an arithmetic mean roughness Ra of less than 0.03 μm.

Description

TECHNICAL FIELD[0001]The present invention relates to a mold for a gasket for a pre-filled syringe and a gasket for a pre-filled syringe produced using the mold.BACKGROUND ART[0002]Recently, the use of pre-filled syringes, which are syringes already filled with a drug, has become popular due to their good user-friendliness and in view of preventing medical accidents such as mix-up of drugs (Patent Document 1). The front end portion of a pre-filled syringe to which a needle is to be attached is sealed with a nozzle cap. Prior to injection, the nozzle cap is removed from the front end portion and a needle is attached thereto. A gasket is then slid by pushing a plunger rod toward the front end portion so that the drug is expelled.[0003]For such pre-filled syringes, silicone lubricants are widely used. However, they cannot be used for those intended for biopharmaceuticals and the like because they cause inactivation of these drugs. Therefore, recently, in order to secure the stability o...

AI Technical Summary

Benefits of technology

[0013]In the mold for a gasket laminated with an inactive film for a pre-filled syringe of the present invention, at least a surface of the mold which forms a seal sliding surface of an annular protrusion of the gasket is mirror finished to have an arithmetic mean roughness (Ra) of less than 0.03 μm. The use of this mold enables the production of a molded product including an inactive film that is laminated thereon and adjusted to have a small surface roughness. Thus, the present invention provides gaskets having excellent air-tightness and liquid-tightness.

Problems solved by technology

However, they cannot be used for those intended for biopharmaceuticals and the like because they cause inactivation of these drugs.

However, when used with a glass or resin syringe, gaskets laminated with a fluororesin film problematically exhibit poorer air-tightness and liquid-tightness than conventional, non-laminated rubber ones.

Even in the case that such a gasket is designed to have an annular protrusion that provides a wider sealing width to improve its sealing performance, the air-tightness and the liquid-tightness are not improved.

Moreover, in the approach to increase the annular rib diameter to increase compressibility, some problems may arise such as difficulty in setting the gasket in a syringe and creases on the stacked film around an annular sealing portion of the gasket.

Still another problem is high resistance against sliding of a piston.

Thus, such approach cannot provide an effective solution.Patent Document 1: JP 2005-185747 A

Images