Bioequivalence of topical generic products. Part 2. Paving the way to a tailored regulatory system

摘要

Hitherto, for the approval of a topical generic drug product, the majority of the regulatory agencies require clinical endpoint studies to prove its therapeutic equivalence in relation to a reference product. Pharmacodynamic studies are also available to support bioequivalence, however, these are solely applicable for corticosteroids. The first strategy is considered the "gold standard", since it can be applied to all drug products. Nevertheless, the high variability intrinsic to topical drug delivery makes this analysis relatively insensitive, costly, time-consuming, besides requiring a large number of subjects. There are, however, alternative methods capable of providing a more rigorous analysis and requiring a lower cost. Amongst them, in vitro methods have sparked considerable attention, not only in the academic field, but also in the pharmaceutical industry and regulatory agencies.