Evaluation of a human bio-engineered skin equivalent for drug permeation studies

Purpose. To test the barrier function of a bio-engineered human skin (BHS) using three model drugs (caffeine, hydrocortisone, and tamoxifen) in vitro. To investigate the lipid composition and microscopic structure of the BHS. Methods. The human skin substitute was composed of both epidermal and derma l layers, the latter having a bovine collagen matrix. The permeability of t he BHS to three model drugs was compared to that obtained in other percutan eous testing models (human cadaver skin, hairless mouse skin, and EpiDerm(T M)). Lipid analysis of the BHS was performed by high performance thin layer ed chromatography. Histological evaluation of the BHS was performed using r outine H&E staining. Results. The BHS mimicked human skin in terms of lipid composition, gross u ltrastructure, and the formation of a stratum corneum. However, the permeab ility of the BHS to caffeine, hydrocortisone, and tamoxifen was 3-4 fold hi gher than that of human cadaver skin. Conclusions. In summary, the results indicate that the BHS may be an accept able in vitro model for drug permeability testing.