Stripped skin model to predict irritation potential of topical agents in vivo in humans

The prediction of the irritation effects of products of low irritation potential remains problematic. An in vivo human model was utilized to define the irritation potential of a topical agent after partial removal of the stratum corneum by cellophane tape stripping.

The tape was applied to and removed approximately 50 times (mean, 50.0 +/- 16.7) from each test site on the volar aspect of the forearm. One site served as the stripping control, receiving tape stripping only. The other test sites received the topical agent and placebo control. Transepidermal water loss (TEWL) was measured before and daily for 5 days. The TEWL values at baseline after stripping represented the point of maximal stripping barrier disruption. The barrier disruption and irritation potential were assessed with TEWL measurements.

The results showed that the model topical agent had no adverse effect on barrier repair, i.e. did not interfere with TEWL normalization.

This model provides a method for the prediction, with exaggerated sensitivity, of chemical irritation and proclivity to enhance or retard water barrier repair. We believe that the model may predict the response of low irritation materials and may be more sensitive than patch testing on normal skin, particularly for products to be used on certain areas, e.g. the face, anus, etc., or even mucous membranes. The model must receive extensive use with chemicals of varying properties in order to define its chemical relevance.