ABSTRACT
Dened as relative bioavailability (BA), bioequivalence (BE) involves comparison between a test (T) and reference (R) drug product, where T and R can vary, depending on the comparison to be performed (e.g., to-be-marketed dosage form vs. clinical trial material, generic drug vs. reference listed drug, drug product changed after approval vs. drug product before the change). Although BA and BE are closely related, BE comparisons normally rely on (1) a criterion, (2) a condence interval (CI) for the criterion, and (3) a predetermined BE limit. BE comparisons could also be used in certain pharmaceutical product line extensions, such as additional strengths, new dosage forms (e.g., changes from immediate release to extended release), and new routes of administration. In these settings, the approaches described in this guidance can be used to determine BE. The general approaches discussed in this guidance may also be useful when assessing pharmaceutical equivalence or performing equivalence comparisons in clinical pharmacology studies and other areas.
