A Mixture of High Molecular Alkyl-dimethyl-benzyl-ammonium Chlorides as an Antiseptic. ∗

Abstract

Recent investigations have shown that certain alkyl-dimethyl-benzyl ammonium chlorides,

possess characteristics highly desirable in an antiseptic or germicide. The product is obtained as a mixture of homologues in which the alkyls represent radicals derived from the fatty acids of coconut oil. The mixture has been found to be quite uniform in composition.

This compound is an amber-colored solid of soap-like consistency. From the solid is generally prepared a 10% aqueous stock solution, which is slightly acid in reaction and which has a surface tension of less than 36 dynes/cm.

Germicidal tests were carried out according to F.D.A. methods.† The cultures of Staphylococcus aureus and Eberthella typhosa used were secured from the Food and Drug Administration at Washington, D. C., the streptococci from the Boston City Hospital, and the other organisms from the collection of the Department of Biology and Public Health at the Massachusetts Institute of Technology.

All the bacteria were cultivated in Reddish broth, with the exception of the Streptococci, which were grown in Bacto-brain-heart infusion containing 0.1% agar. The molds were grown on Sabouraud's dextrose-agar and subcultured in Sabouraud's dextrose-broth.

Table I shows the results of some germicidal tests.

Both Gram-positive and Gram-negative pathogenic organisms were readily destroyed by the ammonium compound in high dilution. The hemolytic streptococcus, E. typhosa and C. hominis were destroyed in the highest dilution at 37°C. Monilia albicans was most resistant at 20°C., but was quickly destroyed by a 1/10,000 dilution.

Effect of Temperature. The germicidal action of the chemical against Staphylococcus aureus and E. coli at low temperatures was determined. At lower than 1°C., S. aureus was destroyed in 10 but not in 5 minutes by a dilution of 1/4,500 (average value), and E. coli by a dilution of 1/1,000. Neither freezing nor storage at above 50°C. for a period of 18 days, caused any apparent reduction in the germicidal action of the chemical.