JPS62137065A - Syringe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a syringe. In particular, it relates to a syringe that can withstand gamma ray sterilization.

[Prior Art] Conventionally, syringes are used to inject various types of pharmaceuticals into the body, so they are required to have excellent chemical resistance, and their outer cylinders are made of polypropylene, polymethylpentene, etc. It was used.

Polypropylene has poor transparency due to its high degree of crystallinity, so nucleating agents such as dibenzylidene sorbitol and its alkyl derivatives are added to improve transparency. That is, by adding a nucleating agent, small crystals were generated and transparency was improved. Sterilization also depends on the material of the syringe.

It was sterilized using ethylene oxide gas.

[Problems to be Solved by the Invention] In recent years, sterilization using gamma rays has become desirable because it is superior to sterilization, considering the safety of sterilization, the ease of operation, and the negative effects of adsorbed residual ethylene oxide gas. ing. However, when polypropylene is irradiated with gamma rays, the polypropylene molecules decompose and its strength is extremely reduced, so syringes made of polypropylene cannot be sterilized with gamma rays. In addition, polypropylene syringes have poor transparency and are difficult to collect, so in order to make the contents of the drug solution easier to see and to improve the product image, dibenzylidene sorbitol and its alkyl derivatives are used. A nucleating agent was added to improve its transparency. Syringes made of polypropylene to which nucleating agents such as dibenzylidene sorbitol and its alkyl derivatives have been added are unfavorable to living organisms because the added nucleating agents tend to elute. Furthermore, in terms of moldability, the nucleating agent contaminates the mold as foreign matter, requiring frequent cleaning of the mold with a solvent such as toluene, and in addition, molded products containing a nucleating agent are susceptible to static electricity. Molding problems such as adhesion of dust and mold release problems have occurred.

Polymethylpentene is an olefin resin that has excellent transparency and is relatively good in terms of eluates, but it has poor impact resistance and is expensive, so it is not suitable for use in the outer cylinder of a syringe.

[Means for Solving the Problems] The present invention provides a syringe composed of an outer cylinder, a separator, and a gas get, in which at least the outer cylinder is made of a synthetic resin mainly composed of a linear ethylene-α olefin copolymer. The above problems were solved by providing a syringe made with.

Generally, when a polymer is irradiated with gamma rays, decomposition and crosslinking occur through ionization and excitation. Produced by gamma irradiation. ions, radicals, and excited species.

Dissociation of covalent bonds and formation of bonds occur in complex ways through ionic and molecular reactions and radical reactions. The main processes are cleavage of polymer chains, dissociation of side chains, and cross-linking between polymer chains. In many polymers, main chain scission and crosslinking occur simultaneously, but there are some polymers in which only main chain scission occurs preferentially, and polymers in which crosslinking occurs preferentially. With γ-ray irradiation, the molecular weight and distribution of the polymer changes, resulting in one-separation type polymers.

The molecular weight gradually decreases, and cross-linked polymers gradually form a network structure, turning into three-dimensional macromolecules. Among various polymers, generally vinyl type polymers belong to the crosslinked type, and vinylidene type polymers belong to the collapsed type.

Polypropylene is a vinyl type polymer, but 1 normal γ
Under wire sterilization conditions, main chain decomposition takes priority and strength decreases.

γ-ray sterilization was not possible.

As a result of intensive research by the present inventors, the linear ethylene-α olefin copolymer has transparency, excellent impact resistance, strength as a syringe, and γ-rays. It was found that the resin did not decompose and no decrease in strength was observed even when irradiated with .

That is, the linear ethylene-α olefin copolymer belongs to the crosslinked type, and irradiation with gamma rays causes partial crosslinking and increases the mechanical strength.

Furthermore, the linear ethylene-α olefin copolymer has less transparency than polypropylene or high-density polyethylene produced by a low-pressure process. Furthermore, the linear ethylene-α olefin copolymer basically does not contain any components that are highly eluting, so it is highly safe.

That is, according to the present invention, it has excellent transparency and impact resistance,
It is possible to provide a syringe that does not contain highly eluted components and can withstand gamma ray sterilization.

The linear ethylene-α olefin copolymer that can be used for the outer cylinder has a density of 0.930 g/c nf
~0.980 g/cnf is preferred. Density is 0.930 g/c-rr? An outer cylinder made of a linear ethylene-α olefin copolymer having a molecular weight of less than 100 ml is soft and easily deforms under the pressure of injecting a chemical solution or the like.

In the airtightness test, water leaked from the contact surface between the outer cylinder and the gasket when a certain pressure was applied, and the product did not meet disposable syringe standards. The airtightness test shall be conducted in the following manner.

After thoroughly wiping off water, inhale the syringe to its maximum scale, 3/4 of the maximum scale, and 1/2 of the maximum scale, and fix it horizontally to prevent water from coming out of the cylinder mouth. When the pressure listed in the following table is applied to the tube mouth for 10 seconds,
There should be no water dripping from the fit.

The density of the linear ethylene-α-olefin copolymer can be increased by decreasing the molar ratio of the α-olefin in the copolymer.

The α-olefins of the linear ethylene-α-olefin copolymer are butene-1, which has 4 carbon atoms, and hexene-1, which has 6 carbon atoms.
1 and 4 methylpentene-1, octene with 8 carbon atoms-
It is preferable that it be the 1st grade.

More preferably, the α-olefin is 4-methylpentene-
1, octene-1 is preferred.

That is, a linear ethylene-α-olefin copolymer in which the α-olefin is 4-methylpentene-1°octene-1 has excellent tensile strength and impact resistance.

A syringe constructed with an outer cylinder made using a linear ethylene-α olefin copolymer having such characteristics can be produced at low cost and is transparent.

It has excellent impact resistance, contains almost no highly leachable components, is highly safe, and can be sterilized by gamma rays.

[Example] The present invention will be explained in more detail below with reference to Examples.

Example 1 By injection molding using a copolymer of ethylene and octene-1 with a density of 0.935 g/cnf.
Outer cylinder 1 and Seiko 2 for 5 m1 were produced. The wall thickness of the produced outer cylinder was 1.5 mm. A natural rubber gasket 3 was attached to the tip of the syringe to assemble the syringe.

After this syringe was sterilized with gamma rays at a sterilization dose of 2.5 Mrad, there was almost no change in the impact resistance of the syringe.

In addition, as a result of conducting an airtight test according to the above method, 2
．． There was no leakage of water even when a pressure of 5 kg/cm'' was applied.

Example 2 By injection molding using a copolymer of ethylene and octene-1 with a density of 0.950 g/CTTI'
Outer cylinder 1 and Seiko 2 for 10 ml were produced. The outer cylinder had a wall thickness of 1+nn+, and a gasket 3 made of natural rubber was attached to the tip of the six suckers to assemble a syringe.

After this syringe was sterilized with gamma rays at a sterilization dose of 2.5 Mrad, there was almost no change in the impact resistance of the syringe.

In addition, as a result of conducting an airtight test according to the above method, 3k
Even when a pressure of g/cm2 was applied, no water leaked.

[Effects of the Invention] One - As described above, the syringe of the present invention has the following advantages.

■ Gamma ray sterilization is possible because the resin does not deteriorate even when irradiated with gamma rays.

■It is safe as it contains almost no substances that are easily eluted.

■It is economical because the price of resin is low.

[Brief explanation of drawings]

The attached figure is a front view showing one embodiment of a syringe according to the present invention.

Claims (3)

[Claims] (1) A syringe consisting of an outer cylinder, a sucker, and a gasket, characterized in that at least the outer cylinder is made of a synthetic resin whose main component is a linear ethylene-α olefin copolymer. syringe. (2) Density of ethylene-α olefin copolymer is 0.9
The syringe according to claim 1, which has a weight of 30 g/cm^3 to 0.980 g/cm^3. (3) The syringe according to claim 1 or 2, wherein the α-olefin of the ethylene-α-olefin copolymer has a carbon number in the range of 4 to 8.