In Reply to Parent Post by phloQS
First of all, thanks for all the responses. Maybe I described my validation approach a bit too short. We will do several test for seal integritiy as well as packaging integrity. The seal integrity is testted trough peel-test, dye-test and burst-test, each with 5 samples where the peeltest is done on each side of the blister so there are four samples for each blister, 20 in alltogether. It is NOT the sterility testing, just the test for packaging (and seal) integrity. We perfom all the described test in five stages: before sterilisation, after sterilisation, after transport simulation after accelerated aging and the last tests after real time aging. What we want to show is, that sterilisation and transport have no bad influence on the packaging. We already have studies for another system with the same study design. The results on each stage are very similar, so the influence of the sterilisation and the transport seem to be very low. The data overall looks very good. Seal strength is far above the limit suggested in standards (DIN EN 868-5:2009). So again from your point of view: would that studydesign be sufficient for an FDA inspection, although we only use five samples for each test (but in total there are 100 samples, twenty in each stage) and have no statisticsal rationale beyond this?
A few remarks:
1. The only thing that statistically counts is repetitions
, i.e. the number of test samples from the exact same configuration
. The fact that you repeat the process at various stages (or repeat the sampling & testing at different pouch locations) does not add to the statistical rigour, unless you analyse them as one "population" (which will also increase the within-sample variation).
2. From all I've seen from the FDA, "no statistical rationale" is bad practice
3. When I referred to "sterile barrier validation" I didn't only relate to the "narrow" aspect of sterility tests; I also related to what you call seal testing or seal validation. It has (IMO) the same level of criticality because it directly afects the end result - sterility of the device when put into use.
4. Seal strength (as demonstrated, for example, in peel tests) is important, but it's not the most important factor (understatement
) when considering sterile barrier quality / reliability. You could have a perfect, consistent strong "seal" (e.g. weld) which is in fact not properly sealing, i.e. not a sterile barrier. I'd put more emphasis on burst / dye tests. BTW, both these last tests are not trivial in terms of establishing the test methods, analysis and pass/fail criteria.
5. Perhaps instead of sampling all 4 sides of the pouch for peel testing, consider getting validation data / certification from the original pouch manufacturer, for the originally sealed 3 sides, and redirect some of your resources into enlarging the sample size from the side you seal (or other tests you perform).