Evaluation of a New Alternative to Primary Draze Skin Irritation Testing Using The Epiderm Skin Model

Michiru Genno1, RyoheiI Yamamoto1, Hajime Kojima2, Hiroaki Konishi2 and Mitch Klausner3

1Technical Research Laboratory, Kurabo Industries Ltd. 14-5, Shimokida-cho, Neyagawa-shi, Osaka, 572-0823, Japan;
2Research Institute, Nippon Menard Cosmetic Co., Ltd., 2-7, Torimi-cho, Nishi-ku, Nagoya, 451-0071, Japan;
3MatTek Corporation, 200 Homer Avenue, Ashland, MA 01721, USA

Original Article AATEX 5(4):195-200,1998
EpiDermTM 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 EpiDermTM 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.

Key words: skin irritation test, skin model, EpiDermTM, detergents, cosmetic products, MTT% assay, singlepoint assay.