A strategy for the assessment of skin corrosion and irritation without animal testing

The approach developed by the authors for the assessment of skin irritation makes maximum use of existing information on similar structures or formulations and incorporates a stepwise strategy to determine firstly, the corrosive potential of a substance. The transcutaneous electrical resistance assay (TER) measures the change in electrical resistance across skin when exposed to substances. Corrosive substances cause a profound loss of transcutaneous resistance which allows the prediction of corrosion potential. If the substance is not corrosive, providing ethical concerns are addressed and resolved, skin irritation potential can be determined in a human volunteer 4 hour skin irritation test. Thus, testing is conducted in the species of concern and obviates the need for cross-species extrapolation. In cases where ethical concerns cannot be resolved, there is increasing evidence that 3-dimensional human skin models can be used to make predictions of skin irritancy. Further research is in progress to understand fully, the relationship between human markers of skin irritation and these in vitro endpoints.