Skin–PAMPA: A new method for fast prediction of skin penetration

The goal of this study was to develop a quick, reliable, and cost-effective permeability model for predicting transdermal penetration of compounds. The Parallel Artificial Membrane Permeability Assay (PAMPA) was chosen for this purpose, as it already has been successfully used for estimating passive gastrointestinal absorption and blood–brain barrier permeability. To match the permeability of the rate-limiting barrier in human skin, synthetic certramides, which are analogs of the ceramides present in the stratum corneum, were selected for the skin–PAMPA model. The final skin–PAMPA membrane lipid mixture (certramide, free fatty acid, and cholesterol) was selected and optimized based on data from three different human skin databases and the final model was found to correlate well to all of the databases. The reproducibility of the skin–PAMPA model was investigated and compared to that of other PAMPA models. The homogeneity of the filter-impregnated lipid mixture membrane was confirmed with Raman microscopy. It was shown that skin–PAMPA is a quick and cost-effective research tool that can serve as a useful model of skin penetration in pharmaceutical and cosmetic research.