Abstract

Bioavailability/Bioequivalence (BA/BE) studies are often conducted in support of marketing applications for drugs and biologics. The Hatch-Waxman Act particularly enhanced the generic drug marketing and the evolution of BE studies after 1984. The Code of Federal Regulations lists pharmacokinetic (PK) study, pharmacodynamic (PD) study, clinical endpoint study, and in vitro study as methods for determining BA/BE. In PK studies, three approaches are used to demonstrate BE: average BE, population BE, and individual BE. With the development of generic products for highly variable drugs and narrow therapeutic index drugs, reference-scaled BE approaches are employed. For certain types of drugs, clinical endpoint studies may be the most appropriate way to demonstrate BE, for which the approaches to demonstrating BE are also well developed.