3-Steps to Stability Testing Success
Aging your test samples doesn’t mean it has to age you
Stability testing is one of the components for being compliant with ISO 11607. Although the standard requirements may be black and white, how we go on this journey is grey. This blog will highlight the key requirements, as well as best practices to achieve success through aging studies.
Understand the Requirements
Not only is understanding the appropriate stability requirements key for a successful aging study, but also the logical application of those requirements as it applies to testing methodology.
Did you know, you may not need contents to conduct stability testing? ISO 11607-1:2019 states that stability testing and performance testing are separate entities. Performance testing evaluates the interaction between the packaging system and the products in response to the stress imposed by manufacturing, sterilization, and handling, storage, and distribution, therefore loss of sterility is regarded as event related rather than time related.
What does this mean to packaging engineers?
The standard allows for separation between performance and stability testing, subjecting stability test samples without contents. Aging of a specific sterile barrier system is independent of the physical configuration or contents. The materials and seals are expected to age the same regardless of their physical configuration or contents if processing of that sterile barrier system is the same. Building a strategy around this will save on resources while providing a higher confidence of successful outcomes and speed to market.
Project planning tools, such as test plans are most often overlooked and the driving force between any successful study.
Temperature boundaries based on characterization of the device and the sterile barrier system materials are considered to apply conservative aging factors appropriately. Using an elevated temperature to reduce aging durations can lead to false positives and failures.
Excessively high temperatures may have an effect on the material that may never occur in the real time or at room temperature. It is important to understand the materials glass transition temperatures (Tg) or the temperature point at which the material properties begin to structurally change, such as warping.
Select the appropriate tests for evaluating test samples for physical properties and integrity such as submersion leak testing, peel testing, etc. Plan to include label verification studies and other key components that are required to function as intended prior to use.
Accelerating aging is like baking a cake, a higher temperature will help bake your cake quicker, but doesn’t mean the cake is edible.
When determine the aging duration, the Q10 = 2 formula is the most often used conservative formula to determine aging durations. Temperature boundaries are considered to ensure the initial aging factors are applied appropriately. It is best practice to not exceed 60°C for the aging temperature. Temperature selection should be limited to prevent any physical material transitions, such as warping. Select a room temperature that represents typical product storage; typical room temperatures range between 20°C to 25°C. If accelerated aging is not applicable, then real time aging is the only option. It is important to define the aging intervals – the market may want to launch with a 3-year shelf life, however as a risk mitigation, consider creating test samples at each aging interval. No one wants to wait 3-years to find out if the study failed.
Ensure you have the correct tests and associated acceptance criteria for evaluation. Because ISO 11607-1 allows for separating performance testing from stability testing, it is vital to draw conclusions between both data sets. For example, comparing stability data should demonstrate over time that it meets or exceeds established performance specifications.
Remember to include real time aging. ISO 11607-1 states that real time aging shall be conducted within 3-months of accelerated aging unless a technical justification is documented. Any failures in real time aging will supersede accelerated aging data, affecting product on the market and must be investigated.
Having failures through stability testing? Need help planning for success and meeting ISO 11607 requirements? Reach out to Network Partners and speak to an industry leading expert who will partner with you for success.