Research Summary
The antimicrobial efficacies of caprylyl glycol and ethylhexylglycerin in an emulsion were evaluated using the USP24-NF19 standard. The minimum concentrations of caprylyl glycol and ethylhexylglycerin required to inhibit Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans within 1 day, and Aspergillus niger within 28 days, were found to be 0.5% and 1.5%, respectively.
A 1:3 mixture ratio of caprylyl glycol and ethylhexylglycerin was selected for further testing of its inhibitory effects on microorganisms prohibited in cosmetics. The evaluation was conducted at concentrations of 0.5%, 1.0%, 1.5%, and 2.0%. Results showed that the minimum concentration to inhibit *S. aureus* within 3 days, and *E. coli*, P. aeruginosa, and C. albicans within 1 day, as well as A. niger within 28 days, was 1.0%.
This developed preservative system offers multifunctional cosmetic ingredients, in addition to providing emollient benefits.
Keywords: cosmetics, preservatives, caprylyl glycol, ethylhexylglycerin.
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