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US-12622985-B2 - Sterilization method for medical rubber part

US12622985B2US 12622985 B2US12622985 B2US 12622985B2US-12622985-B2

Abstract

A sterilization method for a medical rubber part is a sterilization method for a medical rubber part that can include a body made from an elastic material and that can include an inactive resin film stacked on at least a portion of a surface of the body, where the sterilization method can include irradiating a packaging article with gamma ray, the packaging article accommodating a plurality of the medical rubber parts and having an oxygen concentration not higher than 5%.

Inventors

  • Yogun KIDA
  • Kei Tajima
  • Kazuki NOJIRI
  • Yuichiro MATSUTANI
  • Shumpei Morita

Assignees

  • SUMITOMO RUBBER INDUSTRIES, LTD.

Dates

Publication Date
20260512
Application Date
20231020
Priority Date
20221021

Claims (15)

  1. 1 . A sterilization method for a medical rubber part that includes a body made from an elastic material and that includes an inactive resin film stacked on at least a portion of a surface of the body, the sterilization method comprising: irradiating a packaging article with gamma ray, the packaging article accommodating a plurality of the medical rubber parts and having an oxygen concentration not higher than 5%, wherein the elastic material is a cured product of a medical rubber composition containing a (a) base polymer containing a halogenated isobutylene-isoprene rubber and a proportion of the halogenated isobutylene-isoprene rubber contained in the (a) base polymer is not lower than 90% by mass.
  2. 2 . The sterilization method for the medical rubber part, according to claim 1 , further comprising irradiating a packaging article with the gamma ray, the packaging article having an oxygen concentration not higher than 3%.
  3. 3 . The sterilization method for the medical rubber part, according to claim 1 , wherein the packaging article having an oxygen concentration not higher than 5% is a packaging article in which nitrogen is sealed.
  4. 4 . The sterilization method for the medical rubber part, according to claim 1 , wherein the packaging article having an oxygen concentration not higher than 5% is a packaging article in which an oxygen adsorber is sealed.
  5. 5 . The sterilization method for the medical rubber part, according to claim 1 , further comprising performing irradiation with the gamma ray such that an absorbed dose of the gamma ray is not lower than 15 kGy.
  6. 6 . The sterilization method for the medical rubber part, according to claim 1 , wherein the elastic material has a JIS-A hardness not lower than 30 and not higher than 70, and has a compression set not higher than 20%.
  7. 7 . The sterilization method for the medical rubber part, according to claim 1 , wherein the inactive resin is polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer, or ultrahigh-molecular-weight polyethylene.
  8. 8 . The sterilization method for the medical rubber part, according to claim 1 , wherein the inactive resin film has a thickness of 10 μm to 150 μm.
  9. 9 . The sterilization method for the medical rubber part, according to claim 1 , wherein the medical rubber part is a rubber plug for a vial, a cap or a plunger stopper for a syringe, or a rubber plug for a vacuum blood collection tube.
  10. 10 . The sterilization method for the medical rubber part, according to claim 1 , wherein the (a) base polymer consists essentially of the halogenated isobutylene-isoprene rubber.
  11. 11 . The sterilization method for the medical rubber part, according to claim 10 , wherein the medical rubber composition contains a triazine derivative as a (b) crosslinking agent.
  12. 12 . The sterilization method for the medical rubber part, according to claim 11 , wherein the (b) crosslinking agent consists essentially of the triazine derivative.
  13. 13 . The sterilization method for the medical rubber part, according to claim 12 , wherein the medical rubber composition contains no vulcanization accelerator.
  14. 14 . The sterilization method for the medical rubber part, according to claim 12 , wherein the triazine derivative includes a compound represented by a formula (1): wherein in the formula (1): R represents —SH, —OR 1 , —SR 2 , —NHR 3 , or —NR 4 R 5 , where R 1 , R 2 , R 3 , R 4 , and R 5 each represent an alkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkylaryl group, or a cycloalkyl group, M 1 and M 2 each represent H, Na, Li, K, ½Mg, ½Ba, ½Ca, an aliphatic primary, secondary, or tertiary amine, a quaternary ammonium salt, or a phosphonium salt.
  15. 15 . The sterilization method for the medical rubber part, according to claim 5 , wherein the irradiation is performed in a dose that falls within a range of not lower than 1.4 times 25 kGy and not higher than 2.0 times 25 kGy.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) The present application claims priority to Japanese patent application JP 2022-169472, filed on Oct. 21, 2022, the entire contents of which is incorporated herein by reference in its entirety. BACKGROUND Field The present disclosure relates to a sterilization method for a medical rubber part. Background Art Medical rubber plugs for tightly closing openings of syringes, vials, and the like may be required to have many characteristics such as non-eluting characteristics, high cleanability, chemical resistance, resistance to needle piercing, self-sealability, and high slidability. Quality characteristics that may be required of the medical rubber plugs may be required, in terms of use of the medical rubber plugs, to comply with the regulations stipulated in “Test for Rubber Closure for Aqueous Infusions” of the 17th edition of the Japanese Pharmacopoeia, as an example. There is an increasing demand for medical rubber products (syringe gaskets, vial plugs, and the like) to be delivered in a state of guaranteeing sterilization thereof, i.e., to be ready-to-use (RTU). As methods for guaranteeing sterilization, there are methods involving sterilization with high-pressure steam, sterilization with ethylene oxide gas (EOG), and sterilization with gamma ray. The method involving sterilization with gamma ray may have an advantage that a medical rubber product can be sterilized in a state of being packaged and thus can be delivered without opening the package. Meanwhile, the method involving sterilization with EOG may have environment-related issues. In view of this, the method for guaranteeing sterilization tends to be switched to the method involving sterilization with gamma ray. The method involving sterilization with gamma ray may guarantee sterilization by means of absorbed dose setting and actually measured values. If a plurality of medical rubber parts are put into a packaging bag and sterilization with gamma ray is performed, unevenness among the medical rubber parts might occur in the packaging bag. Thus, even when the packaging bag is irradiated with a predetermined radiation dose of gamma ray, variation in the absorbed dose of gamma ray may occur in the packaging bag. This can give rise to: medical rubber parts having low absorbed doses of gamma ray; and medical rubber parts having high absorbed doses of gamma ray. However, it may be necessary to ensure, for each medical rubber part, a minimum absorbed dose with which the medical rubber part can be sterilized. Thus, it may be necessary to irradiate the packaging bag with at least the minimum absorbed dose of gamma ray. This can give rise to medical rubber parts that absorb an excessive dose of gamma ray at the time of sterilization with gamma ray, in the packaging bag. Japanese Laid-Open Patent Publication No. 2002-301133 discloses: a rubber composition containing an isobutylene copolymer as a main component and having a density not higher than 0.95, the rubber composition being for use in a medical rubber plug or a medical rubber product on which radiation treatment is easily performed; and a crosslinked product of the rubber composition. Japanese Laid-Open Patent Publication (Translation of PCT Application) No. 2017-531604 discloses a method for packaging a part (1) made from an elastomer, such as a plug for a pharmaceutical agent container. The method includes: a step of packing the part (1) into a primary bag (10) made from a material substantially impermeable with air; and a step of applying an atmosphere with at least 80% of nitrogen to the inside of the primary bag (10). In the method, the primary bag (10) is put into a secondary bag (20), and the interval between the primary bag (10) and the secondary bag (20) is set to be in a vacuum state. When a medical rubber part is sterilized by being irradiated with gamma ray, cleavage and crosslinking can simultaneously occur in a polymer that forms the medical rubber part. If an excessive dose of gamma ray is absorbed, cleavage of the main chain of the polymer that forms the medical rubber part may be promoted, whereby low-molecular-weight components may be generated. Consequently, the non-eluting performance of the medical rubber part having been sterilized with gamma ray may deteriorate. As the medical rubber part, there is a medical rubber part that includes a body made from an elastic material and that includes an inactive resin film stacked on at least a portion of a surface of the body, from the viewpoint of enhancing non-eluting characteristics and/or slidability. However, if the medical rubber part that includes the body made from an elastic material and that includes the inactive resin film stacked on at least a portion of the surface of the body is irradiated with gamma ray, the inactive resin film may degrade. If the inactive resin film degrades, non-eluting characteristics of the medical rubber part may deteriorate. Therefore, a problem may arise in that