The use of mixtures of topical corticosteroids as a mechanism for improving total drug bioavailability: a preliminary report.

The feasibility of using mixtures of corticosteroids as a mechanism for enhancing total percutaneous absorption of drug has been investigated. The results of this study indicate that under certain conditions, mixtures of corticosteroids exhibit independent solubility, partitioning and diffusion behavior. Mixtures of three 21-esters of fluocinolone acetonide were found to penetrate excised human skin independently. The mixture flux rate was demonstrated to greatly exceed that attained with any of the component steroid esters at an equal concentration. A mixture composition containing a total steroid concentration of 0.015% was shown to produce significantly greater in vivo human vasoconstriction than any of the individual steroids at comparable concentrations. These results strongly support the potential clinical utility of certain topical corticosteroid mixture compositions.