Reconstructed epidermis versus human and animal skin in skin absorption studies

We present a comparison of various in vitro techniques suitable for routine skin absorption studies including commercially available reconstructed human epidermis which may be a reliable alternative to excised human and animal skin. In order to develop a protocol for the subsequent transfer to partner laboratories the experimental set-up was analysed stepwise using the OECD reference compounds caffeine and testosterone. Franz cell type, the donor and receptor media for hydrophilic/lipophilic substances, albumin and tensid addition, and storage conditions of the excised skins were systematically varied. A protocol has been developed which now allows to proceed to the pre-validation process.