Predicting in Vitro Skin Irritation: Use of the Reconstructed Human Epidermis Test Method (EpiDerm^TM SIT) in a 24-h Exposure Test for Skin Irritation

抄録

The Organization for Economic Cooperation and Development established Test Guidelines (TG) for non-animal testing methods to assess the safety of cosmetic ingredients. TG439 utilizes reconstructed human epidermis to assess skin irritation. TG439 are available for evaluating agents after 4-h exposure, but it is unclear whether those methods can be used to estimate skin irritation after 24-h exposure, which is necessary for evaluating non- or only slightly irritating substances, such as cosmetic ingredients, and for pharmaceutical approval in Japan. In this report, we assessed the performance of the EpiDerm^TM SIT (skin irritation test) as an alternative method for predicting slight irritation after 24-h exposure. We tested 40 substances listed by the Skin Irritation Test Working Group of the Japanese Society for Alternatives to Animal Experiments. Evaluation of water-soluble substances had 92% accuracy. Evaluation of oil-soluble substances exhibited only 62% accuracy, 18% sensitivity, and 93% specificity. Although the assay produced a high percentage of false-negative results for oil-soluble substances, positive predictivity was high for all substances. A positive result in the EpiDerm^TM SIT indicates a strong possibility of skin irritation. These results suggest that the EpiDerm^TM SIT is useful for assessing the potential of substances as irritants after 24-h exposure.