Bioequivalence and Bioavailability Forum

Hi John,

❝ I have a question. If somewhere down the road someone wants to analyze the samples beyond long term stability, is it possible? For research purposes, not regulatory. It is doable to extend the long term stability right?

Sure, it is. It just takes time, that's all
If you still have old QC samples, that's quite easy. If you don't: well, you'll have to prepare stability samples, analyse your study samples, and wait for your stability samples to become old enough...

If you still aim for the same analyte, and if it's only for research purposes, you can also just compare the new results to the old ones. If you still find the same result, the samples were (probably) stable. If the result is systematically lower, either the analyte was not stable, or you screwed up somewhere. If the result is systematically higher, either an unstable metabolite got back-converted, or you screwed up somewhere

If you go for a new analyte (metabolite, etc.), first check what information was given to the subjects in the informed consent form. You may have to re-consent them first !