Evaluation of the Influence of Bases, Formulations and Skin Conditions of Two Preparations of Commercially Available Drugs on Permeability and Adverse Effects in Hairless Rat Skin

Abstract

The skin permeability of drugs in ointments varies and depends upon the bases, formulations, and the skin condition. To assess the relationship between permeability of topical drugs, their bases and formulations, and the skin conditions, we attempted in vitro experiments using hairless rats (HR) skin. We selected two kinds of drugs: corticosteroid as a lipophilic drug and urea as a hydrophilic drug. The permeability of both corticosteroid and urea cream across normal HR skin was significantly greater than that of ointments and/or lotion. Stripped skin was found to have a hugher permeability than normal skin. Among the formulations, the percutaneous absoption of both the lipophilic and hydrophilic drugs in lotion was the most increased when the skin condition changed from normal to stripped skin.