LLOQ: higher or lower? [Bioanalytics]

posted by cakhatri – India, 2017-12-04 10:52 (2011 d 22:52 ago) – Posting: # 18033
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Any LLOQ you select, should be based on justification. In general it is 1/32 of the reported Cmax (Cmax*1/32). This is assumed based on the standard calculation of 5 half lives and usually will be sufficient.

Regarding which Cmax to select - You should consider the reported Cmax or if range is available, consider the lower range (if 80-100 ng/mL Cmax, consider 80 and calculate 1/32)

You also should look at the sampling time points in protocol. if that is beyond 5 half lives, the LLOQ should be lowered accordingly

If you are conducting a study with truncated design, the LLOQ need not be 1/32 but higher (1/16 or 1/8) because usually for truncated design the sampling is restricted to 1 or 2 half life and hence LLOQ can be taken higher.

With proper selection of LOQ, you will be able to minimize the BLQ (Below limit of Quantification) values and proper estimation of AUC0-t and AUC0-inf.


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