Gasket using medical silicone rubber having slidability, and syringe using said gasket

• US 10,456,527 B2
• Filed: 04/24/2015
• Issued: 10/29/2019
• Est. Priority Date: 10/07/2014
• Status: Active Grant

• Current Assignee: Coki Engineering Inc.
• Original Assignee: Coki Engineering Inc.
• Inventors: Yotsutsuji, Akira
• Primary Examiner(s): Osinski, Bradley J
• Application Number:
  US15/501,377
• Publication Number:
  US 20170232202A1
• Time in Patent Office: 1,649 Days
• CPC Class Codes: A61L 31/028 Other inorganic materials not covered by A61L31/022 - A61L31/026
• CPC Class Codes: A61L 31/041 Mixtures of macromolecular compounds
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/14 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• 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 2205/025 Materials providing resistance against corrosion
• CPC Class Codes: A61M 5/28 Syringe ampoules or carpules, i.e. ampoules or carpules provided with a needle
• CPC Class Codes: A61M 5/315 Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
• CPC Class Codes: A61M 5/31513 Piston constructions to improve sealing or sliding
• CPC Class Codes: C08L 2203/02 for biomedical use
• CPC Class Codes: C08L 2205/14 containing polymeric additives characterised by shape
• CPC Class Codes: C08L 2207/068 Ultra high molecular weight polyethylene
• CPC Class Codes: C08L 23/06 Polyethene
• CPC Class Codes: C08L 83/04 Polysiloxanes

Abstract

A syringe is to be obtained by using PTFE for a gasket main body that makes a direct contact with an injection solution and using a slidable silicone rubber at a portion that does not make contact with the injection solution.

A syringe A includes a syringe barrel 1, a gasket 10 press-fitted within the syringe barrel 1, and a plunger rod 5 mounted in the gasket 10. In the gasket 10, a concaved groove 18 is formed over the whole circumference of a slide-contact surface 11 of a main body portion 26 that is formed of a rigid plastic having a drug solution-resistant property against a drug solution 30 to be loaded in the syringe barrel 1 and that is configured to slidingly contact an inner circumferential surface 2 of the syringe barrel 1. In a slide-contact ring 19 that is to be fitted in the concaved groove 18 and that is configured to slidingly contact the syringe barrel inner circumference surface 2, a silicone oil and a spherical ultrahigh molecular weight fine powder are added to a silicone rubber base material 19c.

Claims

1. A gasket, for syringes, to be press-fitted in a syringe barrel and used in a slidable manner, the gasket comprising:

a main body portion that is formed of a rigid plastic having a drug solution-resistant property against a drug solution to be loaded in the syringe barrel, and that has a slide-contact surface that slidingly contacts an inner circumferential surface of the syringe barrel; and

a slide-contact ring that is fitted in a concaved groove formed over a whole circumference of the slide-contact surface, and is configured to slidingly contact the inner circumferential surface of the syringe barrel, wherein

within the slide-contact surface, at least a slide-contact surface adjacent to a liquid contact surface with respect to the drug solution is formed to be in contact with the inner circumferential surface and liquid-tight with respect to the inner circumferential surface,

the main body has a liquid-contact side sliding part having the liquid contact surface, the slide-contact surface adjacent to the liquid contact surface, and a back surface contacting the slide-contact ring,

the slide-contact ring is disposed in contact with the back surface of the liquid-contact side sliding part so as to back up the liquid-contact side sliding part,

the slide-contact ring is formed of a slidable silicone rubber obtained by adding a spherical ultrahigh molecular weight polyethylene fine powder to a silicone rubber base material, a filler being added to the silicone rubber base material, wherein a silicone oil is optionally added to the slidable silicone rubber of the slide-contact ring,

when the silicone oil is not added, the slidable silicone rubber contains, in volume ratio, the ultrahigh molecular weight polyethylene fine powder by 44.5 to 60% and the silicone rubber base material containing the filler for a remaining portion, and

when the silicone oil is added, the slidable silicone rubber contains, in volume ratio, the ultrahigh molecular weight polyethylene fine powder by 30 to 65%, the silicone oil by 7 to 40%, a total of the ultrahigh molecular weight polyethylene fine powder and the silicone oil being 37 to 72%, and the silicone rubber base material containing the filler for a remaining portion.

2. The gasket for syringes according to claim 1, wherein

the silicone oil is added to the slidable silicone rubber of the slide-contact ring.

3. The gasket for syringes according to claim 1, wherein a range of particle sizes of the ultrahigh molecular weight polyethylene fine particles is from 10 to 300 μ

m.

4. The gasket for syringes according to claim 1, wherein a material of the silicone rubber base material is obtained by thermally curing an amorphous polysiloxane having a vinyl group incorporated in a molecule thereof and an amorphous polysiloxane having a reactive hydrogen incorporated at a molecule terminal thereof, through a reaction using, as a catalyst, any one of platinum, rhodium, or an organic compound of tin.

5. The gasket for syringes according to claim 1, wherein a material of the silicone rubber base material is obtained through a curing reaction of a polysiloxane having a vinyl group incorporated therein by using a peroxide as a curing catalyst.

6. The gasket for syringes according to claim 1, wherein, the filler including a fine-particle silica as a main component and at least one of a PTFE fine powder, glass beads, talc, a titanium powder, or carbon, is added to the silicone rubber base material.

7. The gasket for syringes according to claim 1, wherein the slide-contact ring is obtained by heating at a temperature not higher than 130°

C. for 4 to 24 hours.

8. The gasket for syringes according to claim 1, wherein a width of the slide-contact surface of the liquid-contact side sliding part is 0.1 to 2 mm.

9. The gasket for syringes according to claim 1, wherein the main body portion of the gasket is a closed-cell PTFE.

10. A syringe comprising a syringe barrel to be filled with a drug solution, the gasket, according to claim 1, press-fitted inside the syringe barrel, and a plunger rod mounted in the gasket.