PK Vs Analytical [Bioanalytics]

posted by Helmut Homepage – Vienna, Austria, 2007-07-24 15:42 (5722 d 21:08 ago) – Posting: # 931
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Dear Charl!

❝ Am looking for a more specific way to determine linearity, from PK point of view,.....

I’m still not getting your point – maybe since your are posting in the ‘Bioanalytics’-category.
You should define a calibration function (which must not be linear, but describing a continous function of detector response from known concentrations) within LLOQ and ULOQ.
LLOQ and ULOQ are defined by PK requirements, whereas the calibration function depends on the analytical method.

❝ If we combined data in a "mathmatical equation" such as Absorption, excretion, inter-subject variabilty, Dose, rate of release in body......

Can we finally have a Model that would give us a close estimation to what we usually end up by the end of the study.

How far can we predict to what degree of details can we go....

That’s an endless story – for sure nothing to be explained in a couple of posts (many people devote their entire lifetimes on small fractions of these topics). I’ll give you some keywords:Yes, there’s software outside; you may e.g., go with Globomax’ NONMEM/PDx-IVIVC, Pharsight’s WinNonlin/IVIVC Toolkit, or even simulations plus’ GastroPlus solving 80 simultaneous differential equations for $50,000…

Anyhow, if you are in doubt whether your method is suitable, why don’t you opt for a small pilot study? FDA states at III.A.2.:

If the sponsor chooses, a pilot study in a small number of subjects can be carried out before proceeding with a full BE study. The study can be used to validate analytical methodology, assess variability, optimize sample collection time intervals, and provide other information.

Edit: FDA-link corrected to latest archived copy. [Helmut]

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