Colloidal carriers of isotretinoin for topical acne treatment: skin uptake, ATR-FTIR and in vitro cytotoxicity studies

Abstract

Acne vulgaris is the chronical, multifactorial and complex disease of the pilosebaceous unit in the skin. The main goal of the topical therapy in acne is to target the drug to epidermal and deep dermal regions by minimizing systemic absorption . Isotretinoin, a retinoic acid derivative, is the most effective drug in acne pathogenesis. Because systemic treatment may cause many side effects, topical isotretinoin treatment is an option in the management of acne. However, due to its high lipophilic character, isotretinoin tends to accumulate in the upper stratum corneum, thus its penetration into the lower layers is limited, which restricts the efficiency of topical treatment. Microemulsions are fluid, isotropic, colloidal drug carriers that have been widely studied as drug delivery systems. The percutaneous transport of active agents can be enhanced by microemulsions when compared with their conventional formulations. The purpose of this study was to evaluate microemulsions as alternative topical carriers for isotretinoin with an objective to improve its skin uptake. After in vitro permeation studies, the dermal penetration of isotretinoin from microemulsions was investigated by tape stripping procedure. Confocal laser scanning microscopy provided insight about the localization of the drug in the skin. The interaction between the microemulsion components and stratum corneum lipids is studied by ATR-FTIR spectroscopy. The relative safety of the microemulsions was assessed in mouse embryonic fibroblasts using MTT viability test. The results indicate that microemulsion-based novel colloidal carriers have a potential for enhanced skin delivery and localization of isotretinoin.