Bioequivalence and Bioavailability Forum

Dear Heema,

❝ [...] overall extent of absorption is of importance for such NTIs.

No, in BE we are interested in the difference of absorption between formulations. Elimination is specific for the drug. After 2-4× t_max the AUC-ratio does not change any more, only variability increases (just saw Kamal Midha walking 'round the corner ). In other words AUC_72(T)/AUC_72(R) ~ AUC_504(T)/AUC_504(R) ~ AUC_inf(T)/AUC_inf(R), but AUC's CV_intra,72<CV_intra,504<CV_intra,inf. Please search the forum for examples and references.

Above said is only true for immediate relase formulations (elimination = slowest phase). For some MR formulations (CR, but not DR) the slowest phase is absorption - the one we are interested in: in such a case truncation does not make sense. Luckily there are only a few stupid controlled release formulations of drug with a long half-life on the market.