Abstract
Effect of cosmetic bases on the antiseptic effect was examined with 7 kinds of 4 types of antiseptics and bactericides chiefly used in cosmetics and 14 kinds of 5 types of nonionic surfactants, on 3 strains of microorganisms. Experiments were made to see the effect of the structure and number of carbon atoms in the alkyl chain in nonionic surfactants on the antiseptic and bactericidal action of these agents, and the following results were obtained. 1) Nonionic surfactants were found generally to inhibit various antiseptics, and this inhibitive action was found to be the strongest in the polyoxyethylenesorbitan alkyl ester type. 2) Nonionic surfactants with larger numder of carbon atoms tended to have greater effect on the antiseptic and bactericidal actions. 3) The inhibitive concentration of nonionic surfactants paralleled the bactericidal concentration. 4) Inhibitive action of nonionic surfactants was found to become stronger with increasing moles of ethylene oxide added. 5) Inhibitive action of nonionic surfactants was found to vary with strain of microorganisms, and the gram-negative organisms used in the experiment tended to receive stronger inhibition than the gram-negative bacteria.
