Process Validation Before/After Sterilization?

ga2qa23

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Hi All, I have a prototype medical device that's a single-use medium-risk handheld tool. It has buttons on the outside and a battery on the inside. I send parts to the vendor who assembles it, does packaging, and does sterilization (via Ethylene Oxide) so it can be sold to customers.

The vendor is already able to do full process validation for the packaging and sterilization, but they only test the product afterwards to ensure that the sterile container isn't compromised (maintains sterility). It's up to my team to determine how to test for functionality. We need to confirm that the product remains functional after shipping testing, and also after sterilization & accelerated aging (for shelf life). Our 'functionality' is basically to prove the buttons work and that the battery lasts for 3 hours of continuous operation.

The FDA regulation 21 CFR § 820.75 "Process validation" requires that "Where the results of a process cannot be fully verified by subsequent inspection and test, the process shall be validated". There are two problems here...
  • I cannot test the functionality of products by 100% inspection because the 'battery test' would be to literally use up the battery by running it for 3 hours.
  • I also cannot test the functionality of products by 100% inspection after the entire process is over, because it would be 'destructive' testing to tear open the sterile container.
Could anyone please help me or point out some resources to read? I already tried reading through the GHTF SG3 Process Validation Guidance for Medical Devices (recognized by FDA): https://www.imdrf.org/sites/default...g3-n99-10-2004-qms-process-guidance-04010.pdf
  1. If our design input requirement states that the battery must last for 3 hours then do I need to literally have a huge batch of devices running for 3 hours? Can I instead just test that the battery is working at all (pass/fail) and also state that the battery OEM has validated the battery to have a certain capacity, which would last 3 hours for the power drawn by my device design?
  2. Am I required to perform a 100% inspection ('functional test') of the product immediately after assembly, before packaging/sterilization?
  3. Or can I instead just 'validate' the functionality of the product after it's been packaged/sterilized/aged?
  4. If I only 'validate' the functionality after packaging/sterilization/aging, then what should my "control plan" look like? Would I have to re-test a small sample size from every future batch manufactured, or could I instead provide some justification that re-testing for functionality isn't necessary until a design change / etc. occurs?
 

ECHO

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I don't have any reading I can point you to but I used to work on a very similar device (minus the battery).

1. For us, all of our design verification was done post sterilization. Therefore, question number 1 was met by pointing to the DVer.
2. Next, after each device was built, we had a quick performance test to make sure everything was working before we sent it to packaging/sterilization.
3. I am not sure what you mean by this. For us, we did all of the functionality testing after sterilization with out aging. We then did it again after accelerated aging, half aged and full. The testing also showed that the functionality of the device was equivalent through out the different durations.
4. I won't retest the functionality unless there was a change in design. You will need a "control plan" to make sure that your design is being "manufactured consistently". For this, I think it will depend on what your volume and manufacturing process looks like.
 

ga2qa23

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Thanks for your reply! I really appreciate getting advice from someone who has this experience. Could I please get some clarification on what you meant by some things...

1. For us, all of our design verification was done post sterilization. Therefore, question number 1 was met by pointing to the DVer.
So did you get a single product post-sterilization and use that for design verification?
Does "DVer" stand for "Design Verification Engineering Report"?

2. Next, after each device was built, we had a quick performance test to make sure everything was working before we sent it to packaging/sterilization.
Was your "quick performance test" different than your full functionality test? (I'm guessing it's limited in-process 100% check and related to an actual process validation).

3. I am not sure what you mean by this. For us, we did all of the functionality testing after sterilization with out aging. We then did it again after accelerated aging, half aged and full. The testing also showed that the functionality of the device was equivalent through out the different durations.
Why did you do functionality testing before accelerated aging, if you did it anyway after accelerated aging? I thought that you could just do functional testing after accelerated aging and it automatically tell you that the device is functional before the aging. (I want to cut down on test samples because we may possibly need to run each unit for at least 4 hours of continuous operation).

4. I won't retest the functionality unless there was a change in design. You will need a "control plan" to make sure that your design is being "manufactured consistently". For this, I think it will depend on what your volume and manufacturing process looks like.
How did you have a "control plan" if you weren't re-testing the functionality periodically? I thought that a "control plan" required periodic sample testing. Forgive me if I'm misunderstanding the term. I thought that "control plan" was synonymous with FDA Performance Qualification (PQ). I attached document someone forwarded me that describes it.
 

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ECHO

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So did you get a single product post-sterilization and use that for design verification?
Does "DVer" stand for "Design Verification Engineering Report"?

Dver = Design Verification. We always pointed to the Verification Protocol since we had multiple instances of the report and we didn't want to update documents every time we reran the protocol.
Not sure what you mean by "single product post-sterilization". We packaged all the devices individually and a "lot" got sterilized using e-beam. We then tested ~30 devices for the verification (I can't remember the exact number). We had a document that had some statistical analysis that showed how many we should test for a particular confidence number.


Was your "quick performance test" different than your full functionality test? (I'm guessing it's limited in-process 100% check and related to an actual process validation).

Yes, we just checked that the buttons were working.

Why did you do functionality testing before accelerated aging, if you did it anyway after accelerated aging? I thought that you could just do functional testing after accelerated aging and it automatically tell you that the device is functional before the aging. (I want to cut down on test samples because we may possibly need to run each unit for at least 4 hours of continuous operation).

Mainly because our accelerated aging took 90 days. We didn't want to wait 90 days to find out we needed to fix something.
We also used the pre-aging data to show equivalence (I am not sure if this was a must).

How did you have a "control plan" if you weren't re-testing the functionality periodically? I thought that a "control plan" required periodic sample testing. Forgive me if I'm misunderstanding the term. I thought that "control plan" was synonymous with FDA Performance Qualification (PQ). I attached document someone forwarded me that describes it.

I feel like every company uses these terms differently :)
Maybe this website will clear things up for you: A Basic Guide to IQ, OQ, PQ in FDA-Regulated Industries
 
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