Bioequivalence and Bioavailability Forum

Hi Nastia,

❝ Through "atavism" I meant something like a tail in human body - smthg that should be dissapeared while evolution.

OK, but atavism works the other way ’round. A baby born with a tail. An anachronism would be using a sliding rule instead of pocket calculator.

❝ May I clarify once more: for non-comparative PK trials of IR do we need only classical global C_min?

Not sure what you mean by “non-comparative PK trial of IR”. For IR you don’t need it at all (C_min,ss was suggested in the draft IR-GL but didn’t make it to the final version). In the comments we find the nice apples-and-oranges sentence:

“By C_min,ss we mean the concentration at the end of the dosage interval, i.e. C_trough.”

Given. Common understanding: C_min,ss = C_trough, which is ≠ C_τ,ss in case of a lag-time. Even without a lag-time due to variability C_min,ss can be observed at the beginning or the end of the dosing interval. Sigh.

In a hybrid application (no MR on the market; comparison to IR or even a solution) I would say C_ss,min. BTW, currently I’m dealing with a hybrid for Canada. It’s a biphasic product with a lag-time. After some to-and-fro: Both C_ss,min and C_τ,ss. Oh dear…

❝ Аnd for MR C_trough (as it is written in the article)?

Yep – if the two Lászlós meant C_τ,ss.