ALTERNATIVE METHODS FOR PHOTOTOXICITY TEST USING RECONSTRUCTED HUMAN SKIN MODEL.
This study by researchers at the Korea Food and Drug Administration (KFDA) demonstrated that MatTek’s EpiDerm in vitro human skin tissue equivalent can be used to determine the phototoxic potency of chemicals. Phototoxicity is defined as a skin inflammatory reaction elicited by topical or systemic administration of chemicals and subsequent exposure to light, particu-larly UVA radiation. Where substances are intended for use in dermatological products applied to the skin, it is necessary to carry out an assessment of potential phototoxic hazard. The aim of this study was to investigate the ability of reconstructed human skin models (H3D PT) in order to identify the phototoxic potency of chemicals. We evaluated the phototoxic potential of 4 UV absorbing chemicals (chlorpromazine, promethazine, rose bengal and bergamot oil) and 4 non-UV absorbing chemicals (penicillin G, sodium lauryl sulfate, Eusolex 9020 and Eusolex 6300) using Epiderm™ (MatTek Corp., Ashland, MA USA), Keraskin™ and Melaskin™ model. The test was based on a comparison of cytotoxicities of a chemical when tested with or without exposure to a non-toxic dose of UVA+ visible light. After chemicals were applied topically to tissues of each model, the tissues were exposed to non-cytotoxic dose of UVA (6 J/cm2). Cell viability was quantified by MTT assay 22 hours after the UVA exposure. Study results showed that chlorpromazine. promethazine, rose bengal and bergamot oil were phototoxic while penicillin G, sodium lauryl sulfate, Eusolex 9020 and Eusolex 6300 were non-phototoxic. These results were well corresponding with data of in vivo phototoxicity test. Meanwhile, three H3D models showed the same results except that rose bengal tended to be non-phototoxic in Melaskin™ model. Thus, these results suggest that the H3D PT is able to be used for discriminating phototoxic and non-phototoxic chemicals efficiently as alternative method appropriate for assessing the phototoxic potency. Also the study evaluated the phototoxic potentials of 2 tattoo pigments (carbazole and cadmium sulfide) using an established method using Epiderm™. Carbazole was identified as an phototoxic substance, while cadmium sulfide was a non-phototoxic substance. This research was supported by a grant (08151KFDA406 and 09161KFDA556) from Korea Food & Drug Administration.
EPI-200, EpiDerm, False positive results, Phototoxicity, Tattoo ink, UV Filter (sunscreen), UVA Radiation
4-Methylbenzylidine Camphor, Bergamot oil, Butyl methoxy-dibenzoylmethane, Cadmium sulfide, Carbazole, Chlorpromazine, Eusolex 6300, Eusolex 9020, Penicillin G, Promethazine, Rose bengal, Sodium lauryl sulfate
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