Skin distribution and pharmaceutical aspects of adapalene gel.

Abstract

The formulation of topical dermatologic products must take into account efficacy, safety, and patient compliance. We describe how an aqueous gel containing adapalene, a novel naphthoic acid derivative was selected for the topical treatment of acne. Dose selection was made using established in vivo models. In the Rhino mouse the comedolytic effect of adapalene 0.1% gel was similar or superior to that of a reference formulation containing 0.025% tretinoin. Qualitative distribution of adapalene after topical application was assessed on cryosections of human skin. They showed rapid penetration of adapalene into the pilosebaceous unit. A liberation/penetration study demonstrated that significant quantities of adapalene were present in epidermis and dermis, but only 0.01% of the applied dose penetrated through the skin. This formulation should result in effective and well-tolerated treatment of acne vulgaris with good patient compliance.