ABSTRACT
The pharmacotherapeutic efficiency of topical drug delivery systems is mainly dominated by the skin distribution of therapeutic agents. In this work, a sensitive, rapid and fully-validated reversed-phase high performance liquid chromatography [RP-HPLC] method was developed to determine finasteride in human cadaver skin after different vesicular formulations were applied. Drug in different depth of skin layers were measured with an EclipseXDB-C18 column. The mobile phase consisted of 75% [v/v] methanol containing 0.2% phosphoric acid buffered to pH 3.0 with triethylamine under isocratic conditions. The system was operated at 40[degree]C and the mobile phase flow rate was set at 1 mL/min. The standard-calibration curve was linear within range of 5 to 200 ng/ml with correlation coefficient 0.9996. The intra-assay precision was less than 3.9% while the inter-assay precision was less than 7.1% with the bias range of - 8.6 to 4.1%. This method was found to be specific, accurate, and sensitive and was successfully used to determine the accumulation of finasteride after in-vitro percutaneous delivery by liposomal or ethosomal drug delivery nanocarriers.