Penetration enhancers assessed by corneoxenometry.

Chemical enhancers abating the barrier function of the stratum corneum act in a number of ways. Their relative effects in mixtures are notoriously difficult to determine. Corneoxenometry is a bioassay where xenobiotic interactions with corneocytes are assessed using reflectance colorimetry. It was used to evaluate comparatively the effects of ethanol and laurocapram at various dilutions. In addition, a 10% propylene-glycol-based gel supplemented with N-acetyl-L-cysteine, urea and salicylic acid in various concentrations was tested. The relative index or irritancy (RII) was calculated for each formulation. RII is a surrogate marker of lipid removal and disorganization, and of protein denaturation in the stratum corneum. It is likely a good predictor for barrier function alterations and represents a cheap and rapid alternative to animal testing. Copyright 2000 S. Karger AG, Basel.