EVALUATION OF A NEW ALTERNATIVE TO PRIMARY DRAIZE SKIN IRRITATION TESTING USING THE EPIDERM SKIN MODEL.

• TR Number: 162
• Keywords: Cosmetics analysis, Cutaneous irritancy, Cutaneous irritation, Cutaneous toxicity, Dermal irritancy, Dermal irritancy testing, Dermal irritation, Detergents, treatment with, Draize skin irritation, Endpoints, MTT, Epi-100, EpiDerm, EpiDerm, MTT, MTT ET-50 tissue viability assay, MTT assay, Personal care products, Single-point assay, Skin irritancy, Skin irritation

EpiDerm™ is a commercially available human skin model consisting of normal human-derived epidermal keratinocytes (NHEK), which have been cultured to form a multilayered, highly differentiated model of the human epidermis. We evaluated this model as an alternative to the primary Draize skin irritation test using rabbits. Eighteen cosmetic products were tested using a new assay system which utilized the EpiDerm™ and a single 24-hour exposure at 100% concentration. The MTT assay results were compared to the results from skin irritation Draize testing using rabbits. The correlation coefficient for 18 test substances between the in vivo and in vitro results was r= – 0.671. However a much better correlation was obtained provided that 2 products, both of which contained high ethanol levels (>60% (w/w)), were excluded from the analysis (r= – 0.870). As such, this method may prove useful in making in vitro skin irritation assays more economical and convenient.