First, I don't think it's fair to say your product will never be exposed to accelerated temperature and humidity. Products are not always held under labeled conditions. Unless you are distributing the product all over the world in reefer trucks, and have signed agreements with your distributors and end-users that they will use temperature controlled warehouses, it will sit in trucks on hot tarmac and uncontrolled warehouses in tropical regions. I would want to know / quantify that risk.
Second, it's generally recognized that the high temperature and humidity of accelerated stability studies may induce failures that will not be seen in real world use of the product. That's why stability studies are always both accelerated and ambient. Accelerated stability gets you to market quicker (at risk) while the ambient stability study is the foundation for your shelf life.
Lots of ways to handle this. You could:
1. Document scientific justification why humidity will not have an impact on your packaging/product. I think you're poking around this, but personally I'd run the study as-is, gather the data, and deal with the outcome. You may learn something you want to know.
2. Document in the protocol that the accelerated temperature/humidity combination may induce failures, even calling out specific ones that you are aware of based on your risk management documentation. Again, this in my experience is not required since it's expected that accelerated can induce artificial failure.
3. Document the accelerated failures in the report and indicate that, based on your engineering knowledge and risk management documentation, they were induced by the accelerated temperature and humidity. Compare to the ambient study at that point, and release at risk. Need to be really confident here between Engineering and QA; if you release to market and later there are ambient failures in your study you have a major problem.
4. Run at a lower temperature / humidity for a longer time frame so that it is less likely to induce artificial failures - but this will delay your market launch.
Good Luck!
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Joshua Lust
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Original Message:
Sent: 29-Jun-2022 02:38
From: Saschka Busch
Subject: Latest ASTM F1980-21 - Aging studies with controlled humidity
Hello together,
the new version of ASTM F1980-21 specifically requires the addition of controlled humidity (45-55% RH) in aging studies when there is concern for an impact on the packaging or material of the medical device.
It is not easy to determine the influence of humidity for each material by literature research or supplier information. A simple example is stainless steel, which is often used in medical devices. Here the opinions are divided between moisture has no influence on stainless steel and stainless steel can oxidize at high humidity, especially if they have been processed previously and not passivated again.
The new passage with the addition of moisture raises questions, and the reported high humidity at the standard 55°C aging temperature can lead to new problems that would never occur under the specified storage conditions of the medical devices. We would like to know and discuss how other persons/companies deal with the question and new requirement and whether controlled humidity has become a must for accelerated aging, if an influence on materials cannot be excluded (acceptance by notified bodies)?
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Saschka Busch
Germany
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