The changes in absorption of ultraviolet light were determined for fifteen sunscreens following two-hour exposures to a sunlamp. Some showed increases (ethyl-paminobenzoate, amyl and phenyl salicylate, menthyl anthranilate, 2-naphthol-6-sulfonic acid, tannic acid, and phenol), some showed decreases (benzyl-salicylate, homomenthyl cinnamate, benzylacetophenone), some showed little change (ethyl-pdimethyl-aminobenzoate, menthyl, homomenthyl, and isoamyl salicylates). The data indicate that under the test conditions employed many sunscreens show relatively high stability withstanding many minimal erythemal doses without much change.
UNBURN PREVENTIVE preparations contain S among other materials constituent chemicals called sunscreens with a marked absorption in the sunburn-producing region of the sunlight (1). Of the various properties desirable in the sunscreen one is a high resistance to photodecomposition on exposure to sunlight. If the sunscreen loses its power to absorb the sunburnproducing radiations of sunlight, it is rendered useless. The sensitivity to light has often been mentioned in the literature ( Z ) , but no systematic investigation seems to have been made.