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"Using Multiple EO Cycles in Performance and Stability Validations"

How many EO cycles should samples be subject to during Performance and Stability validations?

Last Updated On May 1, 2014

Common practice is a single cycle. However, during performance and stability validations of a medical device the MDM may elect to plan for possible re-sterilization. For a variety of reasons, this may occur as a planned or unplanned step in the product life cycle. For example, kit packaging or double packaging is commonly exposed to two cycles. This is done as a contingency plan. If an issue occurs in the secondary packaging, the inner primary package can be repackaged in a new outer package. In this case the inner will be exposed to a second cycle. Additional cycle exposure(s) can result in testing to failure.

Since testing attempts to simulate real-world conditions, for performance and stability it is important to recognize when testing is not representative of a possible actual sterilization cycle. Repetitive sterilization conditioning often becomes a test to failure. For example, in stability studies, environmental conditioning in a chamber can create humidity-to-temperature ratios that can result in failures caused by unrealistic parameters. In performance testing where events can compromise sterile barrier system integrity, a typical sequence of events may involve sterilization followed by environmental conditioning and distribution cycles, but for testing purposes the sequence also includes accelerated aging. Such testing, combining performance evaluations with stability protocols and effectively compounding extreme methods, no longer represents realistic events. Performance and stability testing have different objectives and are conducted using different sterile barrier system samples for these reasons. Performance testing is event related and stability protocols challenges material degradation over time.