Untitled

Abstract

ABSTRACT:The assessment of the bioequivalence of topical products not intended for absorption into the systemic circulation has presented a formidable challenge over the years. In particular, dermatological dosage forms such as creams, ointments, lotions and gels, apart from those containing topical corticosteroids, cannot readily be assessed for bioequivalence using "conventional" methodology and the only recourse to-date has been to undertake tedious, time consuming and expensive clinical end-point trials for such products. Although the human skin blanching assay (HSBA), also known as the vasoconstriction assay (VCA) has been successfully used for dermatological products containing topical corticosteroids but no surrogate methodology for the bioequivalence assessment of other topical dermatological products such as those containing nonsteroidal anti-infl ammatory drugs, anti-fungals, antibiotics and antivirals has been successfully accepted by regulatory agencies. The regulatory agencies and pharmaceutical industries are forging ahead to the development of new surrogate BE assessment approaches for other topical dermatological products. These promising approaches include dermatopharmacokinetic study (DPK), dermal microdialysis (DMD), in vitro studies, pharmacokinetic study (PK), near-infrared spectrometry (NIR), and confocal Raman spectroscopy (CRS). In addition, the expansion of biowaivers for topical dermatological products has been explored by pharmaceutical scientists.