Bioequivalence and Bioavailability Forum

Dear EKY,

❝ Which concentration should be use for bracket study in this experiment? It is need to be at ULOQ and LLOQ concentration, or not?

❝

❝ Can use high and low QC concentration (HQC, LQC) for this experiment as same as the other stability evaluations (in matrix)?

Well, a bracketing approach validates whatever is between the brackets... If you use HQC and LQC working solutions you will not validate the stability of the working solutions below LQC and above HQC. So I would definitely recommend to use LLOQ and ULOQ.

This may seem illogical compared with the stability in matrix, where LQC and HQC are used, not LLOQ and ULOQ. But there is no other choice: when you analyse LLOQ samples, part of your results will be BLQ. Same for ULOQ samples: part of the results will be above the ULOQ. You would need to extrapolate on both sides of the curve, with no information on the resulting precision and accuracy. Not something you want to do to generate pivotal information.