Roguet, R., C. Cohen, C. Robles, P. Courtellemont, M. Tolle, J.P. Guillot, and X. Pouradier Duteil. An Interlaboratory Study of the Reproducibility and Relevance of Episkin, a Reconstructed Human Epidermis, in the Assessment of Cosmetics Irritancy. Toxic. in Vitro. 1998. 12: 295-304. [Reprinted with permission from Elsevier Science]

sodium dodecyl sulfate - 00151-21-3

Reconstructed epidermal models are particularly suited to assessing the tolerance of cosmetic and dermatological products in vitro. Their production in kit form makes them available for screening both raw ingredients and finished products since a large amount of material can be tested whatever their physicochemical properties. However, two conditions must first be fulfilled; they must give reproducible results and be relevant to data obtained in vivo. We tested the reproducibility of data obtained using the Episkin model [cytotoxicity evaluated by the MTT conversion and the release of one of the most active proinflammatory mediator, interleukin 1a (ILa )] on different batches and in various research laboratories. After topical application of sodium dodecyl sulfate (SDS) the overall variability of the IC₅₀ results was 14% of the mean value. Within a given centre and a given batch, the coefficient of variation attributable to the dispersion between kits was 6% for the SDS IC₅₀ determination and 7% for IL1a release measurement. The results obtained with Episkin were then compared with data from primary human skin irritancy testing (48-hr occlusion test and clinical assessment) and rabbit irritancy evaluation (Draize cutaneous test). Analysis of the results obtained with 38 cosmetic products (oils, gels, emulsions, mascaras, and shaving foam, including 19 irritants) revealed good concordance with data obtained in humans. Considering the release of IL1a as in vitro parameter, the test sensitivity, specificity and concordance were 68, 79 and 74%, respectively.