An In Vitro Skin Equivalent for Evaluation of Skin Absorption of Compounds

Abstract : Skin Equivalents (SE) or Human Skin Equivalents (HSEs) are skin substitutes that can serve as models for testing the skin permeability of agents from formulations, or for evaluation of formulations themselves on the skin. We have developed a collagen based HSE and HSE containing electrospun poly(DTE carbonate) polymer scaffolds in our laboratory. The culture of these full thickness skin equivalents has been optimized by modification of the culture media and conditions required for growth in order to mimic the barrier properties of human skin in vivo. The HSE has been characterized for morphology, lipid composition and barrier properties and compared to a commercially available skin equivalent, and shows similar permeability to a wide range of agents. Skin derived cells were found to populate and proliferate in the electrospun scaffold, which imparts structural stability to the collagen based HSE model. Use of cocultures of human dermal fibroblasts and human keratinocytes, and conditions such as addition of ascorbic acid are being used to look at effects on morphogenesis and barrier properties of the epidermal layer in these HSE models. Once developed, these skin equivalents can serve as effective models for determination of the permeation of chemical warfare agents (CWAs) or their mimics or the barrier properties of creams such as SERPACWA (Skin Exposure Reduction Paste Against Chemical Warfare Agents).