Cetyl Pyridinium Chloride : I. Germicidal Properties.

Cetyl pyridinium chloride is a cationic detergent which is soluble in water, chloroform, alcohol, and acetone. Aqueous solutions are clear, colorless, and odorless. The agent has a depressant action upon surface tension. This property enhances the value of the germicide because irregular surfaces are uniformly wetted. The germicidal properties of cetyl pyridinium chloride were first studied in this laboratory. Shelton et al. (1939, 1940) described the properties of a series of a quaternary ammonium salts and also the effect of the length of the alkyl chain upon germicidal power. Blubaugh et al. (1939, 1940, 1941) briefly described the germicidal activity of cetyl pyridinium chloride. Green and Birkeland (1941) reported studies on the sporicidal activity of this compound. They concluded that the spores of Clostridium perfringens, Clostridium sporogenes, Clostridium tetani, Bacillus anthracis, and Bacillus subtilis were killed under the conditions of the test. These workers reported a curative effect of the compound on artificially infected chick embryos (Green and Birkeland, 1942; Green, 1944). Huyck (1945) demonstrated that a 1:4,000 dilution of cetyl pyridinium chloride was "bacteriostatic or bactericidal to bacteria found in the oral cavity." Huyck (1944) also described the physical and chemical properties of cetyl pyridinium chloride and reviewed the literature on the quaternary ammonium salts. Warren et ai. (1942) found that dilutions of 1:100 or 1:250 produced some reddening of scarified rabbit skin, but that greater dilutions were without harmful action. Subcutaneous injections of a 1:100 dilution in phosphate buffer produced slight edema and reddening at the site of injection, but higher dilutions had no untoward effect. These results indicate that for topical application or for wound cleansing cetyl pyridinium chloride is essentially nontoxic in the concentrations generally used. It is the purpose of this paper to report the germicidal activity of cetyl pyridinium chloride against a variety of organisms, and the effect of temperature, pH, and presence of protein upon the germicide.