Bioequivalence and Bioavailability Forum

Hi again ssussu,

❝ Then if I choose truncated AUC0-72 instead of AUClast and AUCinf in the protocol，while most of the subjects half-life is not long enough (i.e 18hr) , actually, in this situation, it is possible the time point of 72hr sample concentration is BQL or can not be detected, then what I shoud do?

Well... it would be a bit unusual to this often when the drug generally has an excessive long half-life but OK it might happen. Between-subject variability etc.
You may need to invest at least 90 seconds of your time in figuring this one out with pen and paper. You have some subjects that go below the LLOQ, which means they comfortably display an elimination phase. From those subjects you can routinely derive an elimination constant and extrapolate AUClast (least measurable) to AUCinfinity. This is where you sadly need to invest this obscenely large amount of your precious time: use the same logic and jommetry and extrapolate areas to 72 hrs. in stead of infinity. You'll end up with a full data listing of AUC72 estimates, and Bob's your uncle.
Good luck.