Contact photoallergy testing of sunscreens in guinea pigs.
The potential of 3 sunscreens (p-aminobenzoic acid, 4-isopropyldibenzoylmethane and homosalate) and 2 known human photoallergens (musk ambrette and tetrachlorosalicylanilide) to cause photoallergy, phototoxicity, and/or contact sensitization was determined using a guinea pig photoallergy model, as previously described by Harber and associates. The model was slightly modified by employing 6 exposures over 2 weeks and using Hill Top Chambers for application of the test material. Contact photoallergy was detected in guinea pigs treated with musk ambrette or tetrachlorosalicylanilide (TCSA), although with TCSA, a lower incidence of contact sensitivity and phototoxicity was also detected. The results of studies conducted with sunscreens showed that p-aminobenzoic acid was photoallergenic, whereas homosalate and 4-isopropyl-dibenzoylmethane (Eusolex 8020) were not. However, contact sensitization, and to a lesser degree primary irritation, was detected with Eusolex 8020 at the concentrations employed in this study. The results of these studies suggest that this guinea pig model is a suitable model for assessing the photoallergic potential of various compounds, including the sunscreens tested in this study.
Gerberick
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Procter and Gamble, Miami Valley Laboratories, Cincinnati, Ohio 45239-8707.
Ryan
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D010129:4-Aminobenzoic Acid / Q000009:adverse effects; D000818:Animals; D001565:Benzoates / Q000009:adverse effects; D047188:Chalcones; D004195:Disease Models, Animal; D006168:Guinea Pigs; D010328:Patch Tests; D010787:Photosensitivity Disorders / Q000175:diagnosis* / Q000209:etiology; D012459:Salicylates / Q000009:adverse effects*; D013473:Sunscreening Agents / Q000009:adverse effects*
D001565:Benzoates; D047188:Chalcones; D012459:Salicylates; D013473:Sunscreening Agents; C049936:4-isopropyldibenzoylmethane; D010129:4-Aminobenzoic Acid; C060446:homosalate