A COMPARISON OF PHENYLPROPANOL (0.5%) WITH CHLOROFORM (0.25%) AND AN ADMIXTURE OF METHYL HYDROXYBENZOATE (0.06%) AND PROPYL HYDROXYBENZOATE (0.03%) AS PRESERVATIVES IN LIQUID MEDICINES

The effectiveness as a preservative in liquid medicines of phenylpropanol 0.5%, chloroform 0.25% and an admixture of methyl hydroxybenzoate 0.06% with propyl hydroxybenzoate 0.03% has been evaluated by determination of sterilization times. Phenylpropanol was as effective as chloroform against Escherichia coli and Staphylococcus aureus; in some mixtures phenylpropanol was more rapidly bactericidal than was chloroform against Pseudomonas aeruginosa. The admixture of hydroxybenzoates was a poor preservative. Problems in the preservation of paediatric chalk mixture were solved by the use of sterilized chalk and the replacement of tragacanth by derivatives of starch.