Testing Programs for Sterilization Packaging Systems Used in Health Care Facilities
The FDA regulates sterilization packaging used for medical devices intended for use in health care facilities. This includes sterilization wraps, sterilization packs, sterilization pouches, sterilization containers, sterilization trays, sterilization cassettes and related components such as trays, holders or mats.
A manufacturer must demonstrate that the packaging system allows for sterilization of the enclosed medical device and is able to maintain sterility of the device until it is used.
The FDA Draft Guidance document entitled “Premarket Notification [510(k)] Submissions for Medical Sterilization Packaging Systems in Health Care Facilities” defines the performance information and testing requirements necessary for packaging systems. LexaMed has extensive background and knowledge in this area and years of experience in conducting the testing. Our testing programs comply with ANSI/AAMI ST79 Comprehensive guide to steam sterilization and sterility assurance in health care facilities and with the Association of Operating Room Nurses (AORN) standard.
LexaMed offers both Ethylene Oxide and steam sterilization capabilities in-house and can duplicate typical hospital sterilization cycles as defined in AAMI standards. LexaMed can also coordinate product exposures in the STERRAD sterilization system. This study program includes the following and can be performed in-house and/or coordinated through an outside approved vendor:
- Sterilant Penetration – Using a maximum load configuration, Biological Indicators (BIs) are placed inside packaged products in the most difficult areas to reach, processed in a sterilization half cycle then tested for lethality to demonstrate sufficient sterilant penetration. In some cases temperature probes are used in the chamber and in the packages to show adequate sterilant penetration.
- Package Integrity (Physical Properties) – Physical properties of the packaging are evaluated pre and post sterilization to demonstrate properties such as tensile strength, thickness, tear resistance, burst value and seal strength.
- Package Integrity (Microbial Barrier Properties) – Microbial barrier properties of packaging are evaluated following sterilization. Replicates of the packaging material are subjected to an aerosol challenge of Bacillus atrophaeus spores, any spores that may pass through the material are collected on membrane filters and enumerated. This procedure is based on the ASTM F1608 Standard Test Method for Microbial Ranking of Porous Packaging Materials document.
- Maintenance of Package Integrity (MPI) – This study is designed to evaluate the performance of the packaging material and its ability to maintain sterility under simulated typical hospital conditions. Packs are prepared with the test product following hospital wrapping procedures as defined in AAMI ST79. Negative and positive control packs are prepared to evaluate the effectiveness of the sterilization process Bioburden packs are prepared to evaluate the storage conditions and test packs are prepared to evaluate the ability of the packaging material to maintain an effective sterilization barrier over a specified storage time.
Following sterilization the test packs are subjected to a 3 day handling event designed to simulate how packs are handled in a hospital setting. After this event the packs are stored in a storage area designed to simulate storage in a Hospital Central Supply area. The room is a dedicated, clean area that is temperature and humidity controlled as specified in ST79 and environmentally monitored for viable contamination. While in storage the packs are subjected to weekly handling events meant to simulate hospital use until they are moved to the LexaMed Class 100 cleanroom for sterility testing.
- Drying Time – Drying of the contents inside the packages is necessary to prevent contamination during storage. For steam sterilized products a wet pack evaluation is conducted on 5 packs processed in the steam sterilization cycle. Packs are weighed pre and post sterilization to determine the amount of moisture present in the pack. As stated in AAMI ST79, if <3% weight increase occurs the dry time is considered acceptable.
- Aeration Time and EO Residuals – For EO processed products, an EO residual analysis is conducted, following the specified aeration time, to determine if the time is sufficient to remove EO residuals. AAMI ST79 suggests 12 hours at 48°C as appropriate aeration conditions for health care EO sterilizers.