Api, A. M. In Vitro Assessment of Phototoxicity. In Vitro Toxicol. 1997. 10(3): 339-350.
8-methoxypsoralen - 00298-81-7; isopsoralen - 00523-50-2; 7-methoxycoumarin - 00531-59-9; methyl-n-anthranilate - 00085-91-6
A major criticism of many of the in vitro phototoxicity assays currently under development is that they have been used to test only water-soluble materials. In this study, seven water-insoluble materials were selected for testing in an in vitro phototoxicity assay using a human skin model, Skin2Ô . The results show that 8-methoxypsoralen, isopsoralen, 7-methoxycoumarin, and methyl-n-methylanthranilate were phototoxic when evaluated in this test system. Coumarin, at concentrations up to 5%, was not phototoxic. These results are the same as those found in vivo in animals and humans. At higher concentrations, musk ambrette was phototoxic; however, these observations were not confirmed when the experiment was repeated. In humans, musk ambrette is a photoallergen, but not phototoxic. Thus this in vitro test method accurately identifies the materials that were found to be phototoxic in humans. Experiments conducted with undiluted diethyl phthalate show that the material is toxic to the Skin2Ô tissue. It was possible to test the undiluted material in this assay at an exposure time of 1 hour rather than 16 to 24 hours, but a different exposure time would require extensive testing to validate this modification of the test method.