RE : Statistical powerfor AUC and Cmax

From: "Masson, ric" Subject:RE : [NMusers] Statistical powerfor AUC and Cmax Date:Sat, 29 Jun 2002 22:10:42 -0400 BE are typically powered based on the intra-subject CV of Cmax, and AUC. In most cases, Cmax exhibits greater variability than AUC since it is affected by not only F and Clearance, but also V and Ka; this is true for most drugs but there is exception. Thus, typically BE studies usually fails on Cmax. For US, since the criteria (90% CI within 80-125%) is based on both Cmax, and AUC, the study should be powered on the most variable parameters, usually Cmax. For regulatory approval, Cmax and AUC are considered as two separate outcomes. Cmax not only provide a matrix comparing rate of absorption but also maximum exposure, whereas AUC reflects total exposure. ?ric Masson, Pharm.D. Senior Director, Scientific and Regulatory Affairs Anapharm Inc.