Stability of Diluted Chlorhexidine Gluconate and Benzalkonium Chloride with High-pressure Steam Sterilization

Abstract

We investigated the stability of 0.05% chlorhexidine gluconate solution (CHG) and 0.05 % benzalkonium chloride solution (BAC) sterilized by high-pressure steam. When CHG was stored at 70°C and 90°C for 21 days, the residual rate decreased to 64.6% and 21.0%, respectively. When CHG was stored at room temperature (R. T.) for 12 months, the residual rate decreased to 84.7%. CHG stored at R. T. for 6 months was completely effective against Escherichia coli and Candida albicans, but not Staphylococcus aureus by the bacteriological test. On the other hand, BAC was stable at high temperature and under the light, and the initial concentration of BAC was kept unchanged for 12 months at R. T.