Bioequivalence and Bioavailability Forum

Ahoy d_labes,

❝ • What do you think where to locate Tlag? Between 0 and 0.5 h or between 1.5 and 2 h?

❝ • Is it reasonable to state a definition like: Tlag was defined as the time prior to (or at the first of) two consecutive Concentrations >LLOQ?

I do not have a really useful input to your question, but as often before I have an unqualified opinion.
I think your situation would merit a case-by-case assessment. I do not consider it likely that the true concentration rises to 12 after a <LLOQ and then truly drops back to <LLOQ twice and then skyrockets.
Assay variability may cause a concentration truly <LLOQ to be measured as >LLOQ etc, and that could be a likely explanation in your case. Along the same lines it could also be that the last <LLOQ is truly >LLOQ but recorded <LLOQ due to assay variation.
I am thus sure in your dataset random variation plays a role. If I were a regulator I'd probably have accepted if an applicant argued that lag time should be reflecting the time of the last <LLOQ before the median Tmax . Or sumfin like that.

❝ • Do you know of any software which has implemented such?

You are equipped with the power to write clever scripts ?


Best regards from the Behring Sea
EM.