ABSTRACT
Bioavailability (BA) and bioequivalence (BE) are very closely related. Bioavailability usually focuses on the release of the active ingredient/active moiety from the drug product to one or more sites of action. Bioequivalence focuses primarily on the comparison of the measures of release of the active moiety (drug substance) between two (test and reference) products. Studies based on BE principles are useful during drug development and approval of a new chemical entity drug product during the IND/NDA period to link between various formulations, to examine the effect of various factors on BA of the drug, and to study the pharmacokinetics of the drug. Bioavailability and bioequivalence principles have been discussed exten-sively in Chapters 2, 9, 17, and 19 of this book. Bioequivalence assessment is a dynamic and evolving discipline with complexities. It has evolved
significantly during the past few years. Significant information on this rapidly evolving field may be found in the literature [1-10].
