Bioequivalence Assessment Of Topical Dermatological Dosage Forms

Abstract

There is an urgent need to bring topical generic drug products to the market. However, unlike generic oral dosage forms where standard bioequivalence procedures are based upon well-established procedures and regulatory guidelines, methods for the bioequivalence assessment of topical dosage forms, apart from topical corticosteroid products, have not yet been established. Currently, in most regulatory jurisdictions around the world, clinical end-point studies in patients are usually required. Hence, assessment of the in vivo local cutaneous bioavailability of skin targeted topical dermatological dosage forms is considered as the basis for bioequivalence evaluation between an appropriate topical reference product and the generic formulations. Establishing bioequivalence between topical products is necessary to ensure that patients receiving multisource drug products are assured of the same efficacy and safety as the brand product. Since locally acting topical formulations do not target the systemic circulation, conventional methods of assessing bioequivalence using plasma levels are not appropriate. Consequently, current regulatory guidelines require comparative clinical trials to be carried out to show bioequivalence between topical products. As these studies are very expensive and time consuming, the development of a more direct and relatively rapid and economical method for determining bioequivalence of topical products is required. I ABSTRACT The aim of this research is to develop and evaluate in vitro release testing (IVRT) and in vivo tape stripping (TS) techniques, to assess the dermal bioavailability and subsequent application for the bioequivalence assessment of acyclovir topical cream formulations. Acyclovir, indicated in the treatment of Herpes labialis (cold sores) is formulated as semi- solid topical dosage forms and marketed in various countries. Since the formulations of these acyclovir products may differ from country to country, this study was undertaken to compare the in vitro (IVRT) as well as in