The FDA defines medical device shelf life as, “the term or period during which a device remains suitable for its intended use.” Fitness for use can be impacted by both maintaining sterility of the medical device package and ensuring the device performs as specified after aging. A risk-based approach should be used to determine the potential impact of using a device that may no longer be fit for use. Some medical devices will experience degradation over time and the risk of that degradation to the device’s fitness for use must be assessed when determining specifications and tolerances for manufacturing and components.
A stability study must be conducted on the sterile barrier system. Packaging samples (not containing the product) typically undergo both accelerated and real-time testing to establish the shelf life of the seal. Accelerated testing is allowed for market launch but must be followed up by real-time data. Accelerated aging should follow ASTM F1980, which details the Arrhenius equation that is commonly used. This equation is based on the principle that every 10°C increase in temperature doubles the reaction rate. Both accelerated and real-time aging should be done on medical device packages that have undergone worst-case sterilization.
Stability testing can take many avenues including material strength testing as well as visual inspection and functional testing. The medical device stability tests should be conducted on a packaged product that underwent worst-case sterilization and simulated distribution.