title: Indoor and outdoor efficacy testing of a broad-spectrum sunscreen against ultraviolet A radiation in psoralen-sensitized subjects.
abstract: The efficacy of a sunscreen containing an investigational drug, butyl methoxydibenzoylmethane in combination with padimate O against the erythemogenic effect of ultraviolet A (UVA) radiation was evaluated in two double-blind studies involving subjects sensitized with topical 8-methoxypsoralen. UVA radiation was supplied from either a filtered solar simulator (indoors) or filtered sunlight (outdoors). Five formulations were tested: 3% butyl methoxydibenzoylmethane and 7% padimate O, 7% padimate O, 5% octyl salicylate, and 3% oxybenzone, 3% butyl methoxydibenzoylmethane alone, 7% padimate O alone, and vehicle. Sunscreen protection against the erythemogenic effect of UVA radiation was expressed as phototoxic protection factors. The phototoxic protection factor for each sunscreen was derived from a ratio of the minimal phototoxic dose of UVA radiation that produced delayed erythema on sunscreen-protected and unprotected skin. The combination of 3% butyl methoxydibenzoylmethane and 7% padimate O provided significantly greater protection than the other sunscreen formulations, and for each sunscreen the phototoxic protection factors determined indoors and outdoors were comparable.
mesh_terms: D010129:4-Aminobenzoic Acid; D000328:Adult; D062365:Aminobenzoates / Q000627:therapeutic use; D001565:Benzoates / Q000627:therapeutic use*; D047188:Chalcones; D004311:Double-Blind Method; D004341:Drug Evaluation; D004890:Erythema / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D011564:Furocoumarins / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010787:Photosensitivity Disorders / Q000139:chemically induced*; D011427:Propiophenones; D012867:Skin / Q000528:radiation effects; D013473:Sunscreening Agents / Q000627:therapeutic use*; D014466:Ultraviolet Rays / Q000009:adverse effects*; D062366:para-Aminobenzoates
chemical_list: D062365:Aminobenzoates; D001565:Benzoates; D047188:Chalcones; D011564:Furocoumarins; D011427:Propiophenones; D013473:Sunscreening Agents; D062366:para-Aminobenzoates; C049935:avobenzone; D010129:4-Aminobenzoic Acid; C041981:padimate-O