Assessment of the Skin Irritancy Potential of Synthetic Detergents (Syndets)

Abstract

Summary Among the factors which determine the degree of damage to the skin are (a) the resistance of the stratum corneum to the solubilisation of its components, (b) the intrinsic toxicity of the compound, and (c) the susceptibility of the viable cell layers to damage. In this study of the toxicity of syndets we have attempted to compare their properties in vivo and in vitro and relate these to cutaneous irritancy studies in normal volunteers. The “solubilising” effect of a series of syndets has been studied using the forced desquamation technique. Although no differences could be determined in terms of the corneocytes released from the skin surface, the protein solubilised did differ according to the syndet used and a rank order could be obtained. The susceptibility of viable cells to lysis by syndets has been studied in vitro, using human skin fibroblasts. This test system was able to discriminate between the different syndets and gave the same rank order as the in vivo human test. Comparison with the standard cutaneous irritancy test indicated some correlation between the two test systems and the irritancy test. However, the rank order correlation did show some discrepancy, and the use of such test systems as predictors of cutaneous irritancy is still being investigated.