USE OF AN IN VITRO SKIN MODEL TO PREDICT CHEMICAL CORROSIVITY.

The U.S. Department of Transportation now requires companies to assess the skin corrosivity of raw materials and products in order to insure their safe transport. The United Nations has issued guidelines and assigned packaging groups to materials based on how quickly corrosion of skin occurs in animal studies: I: less than 3 minutes, II: 3 minutes to 1 hour, III: 1 hour to 4 hours, and Non-corrosive: greater than 4 hours. It was anticipated that EpiDerm™, a model of the epidermis cultured from neonatal foreskin-derived normal human epidermal keratinocytes, would be useful in predicting skin corrosivity since the barrier properties of EpiDerm have been shown to closely approximate those of normal skin. Using the MTT assay (based on the capability of mitochondria in viable cells to reduce the MTT dye, 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide) with the exposure times identical to those used in the UN (animal) protocol, the EpiDerm model’s MTT response was a good predictor of the UN packing groups. In this initial study performed by scientists at S.C. Johnson Company and MatTek Corp., which included 22 pure compounds and 17 final product formulations, the correct packing group was assigned in 77% (30/39) of the test materials with 4 of the materials being over-predicted by one packing group. Thus, 87% (34/39) of the materials were assigned to the same or safer packing group. In addition, 97% (38/39) were assigned the proper corrosive/non-corrosive designation. These initial studies indicate that EpiDerm appears to be a valuable means of assessing skin corrosivity using a mechanistic, non-animal, human derived assay system.

Barrier properties formation, Chemicals, Corrosion, Corrosivity, Corrosivity testing, Dermal corrosion, Endpoints, MTT, EpiDerm, MTT, MTT ET-50 tissue viability assay, MTT assay, Packing Groups, Skin corrosion, Skin corrosivity, Skin models, cultured, U.S. Department of Transportation (DOT)