Bioequivalence and Bioavailability Forum

Dear Ohlbe!

❝ ❝ 'Incurred Sample Re-analysis' (is this really English?)

❝ US English, it seems

I guess so; quoting Nick Holford at David Bourne’s PKPD-list:
“I have no opinion about ‘incurred samples’ – an expression which has no easily understandable meaning for me in the English language.”

❝ I attended the AAPS/FDA workshop in Crystal City last year.

Was it as ‘lively’ as the first Crystal City Conference (people shouting at each other…)?

❝ FDA only stated that they wanted precision to be demonstrated on "incurred samples", not just on artificial, spiked samples.

Nice, but what’s the use of it?
To be honest, I’m not interested in the precision of ‘real-world’ samples, but in their accuracy, which can’t be determined anyway – simply because we don’t know the true concentration.
It sounds a little bit hypocritical to me- just imagine the situation of a precise but inaccurate measurement, which will would satisfy the FDA, but yield in ‘rubbish’ data…

At least for bioequivalence studies analytical variability hardly matters at all; if you were able to demonstrate BE – despite an awful analytical method – all questions regarding analytics should subside!
In real life analytical variability is just negligible compared to biological variability (intra- and inter-subject).*

❝ They declined to detail how they wanted it to be done,...

I want to start a little survey:
[ ] Yes: I want to waste precious samples to satisfy the FDA
[ ] No : I want to keep samples, in case I have to re-analyse them (invalid run, etc.)

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• Gaffney M. Variance Components in Comparative Bioavailability Studies. J Pharm Sci 1992;81(4):315–7. doi:10.1002/jps.2600810402.