Importance of the field: The ultimate goal of bioequivalence is to assess the expected in vivo equivalence of two drug products of the same active moiety.
Areas covered in this review: In this review, we present the classic approach of bioequivalence assessment, some situations of special importance such as the role of metabolites and highly variable drugs, and the current regulatory state in North America and Europe. Special emphasis is given to the methods proposed for solving the problems caused by high variability such as multiple-dose studies, replicate designs, individual bioequivalence and the widening of bioequivalence limits. Other issues discussed include the concept of biowaivers and the rising field of the equivalence of biologicals (biosimilars).
What the reader will gain: The reader will gain an understanding of why bioequivalence assessment is necessary, how it is performed and what one should be aware of when planning to conduct a bioequivalence study.
Take home message: The aim of bioequivalence studies is to ensure comparable in vivo performance of two drug products. This is accomplished by performing an appropriate clinical study which should be capable of ensuring the drug's safety and efficacy for consumers with less human exposure and costs of producing.