Best Practices in Sterilization of Rubber Articles
Pharmaceutical closures used in aseptic environments must be introduced in a sterile state. The most common methods to sterilize rubber closures (e.g., stoppers) are autoclaving (saturated steam) and gamma irradiation. Both methods can influence chemical (e.g., extractables profile) and physical/functional properties (e.g., break-loose and extrusion forces). Therefore, it is important to choose the right method.
To meet the diverse needs of customers, West offers a broad portfolio of rubber stoppers and plungers, as either:
- Westar® Ready-to-Use (RU) sterile components – washed and ready to use in a STERIlizableBAG™ or ported bags (sterilized by autoclave), or
- Westar® Ready-to-Sterilize (RS) components – washed and ready to sterilize in a STERIlizableBAG™ or ported bags
For Westar RU sterile components, assurance is to a sterility level (SAL) of 10-6 or better, i.e., probability of microbial contamination is no greater than one component per one million (Guidance for Industry: Container Closure System Integrity Testing Lieu of Sterility Testing as a Component of the Stability Protocol for Sterile Products – https://www.fda.gov/RegulatoryInformation/Guidances/ucm146074.htm)
Westar RS components must be sterilized by the pharmaceutical company. West typically recommends autoclaving: (a) a steam cycle at a minimum temperature of 121.1°C (not to exceed 123°C) for a maximum of 60 minutes, followed by (b) a drying cycle at 105°C for a maximum of 8 hours. For select applications, gamma irradiation may be the right choice. Whatever method is used, the pharmaceutical company must ensure that sterilized components meets sterility and compendial standards (USP <381> and EP 3.2.9).
West Technical Customer Support can assist in selecting the right sterilization method, and in collaboration with Analytical Laboratory Services, to perform compendial tests.
STERIlizableBAG™ and Westar® are registered trademarks or trademarks of West Pharmaceutical Services, Inc. in the United States and other jurisdictions.