Effect of the Sulfate Ion on the Stability of Hibitane Concentration in the Service City Water

It is known that the the hibitane concentration (H-C) is precipitated by the sulfate ion contained in the service city water. We found that the higher concentration of the surface active. agent (polyoxyethylene nonylphenylether, NP-10SM) prevented the precipitation. The H-C containing the various concentrations of the NP-10SM were diluted with the sulfate ion solution of the various concentrations. We tested the appearance and quantifiction. 1) In the appearance, the 7% NP-10SM for the 5% chlorhexidine gluconate (CHG) prevented the precipitation in the 3Oppm sulfate ion solution. The 3.75% NP-10SM for 5% CHG prevented the peccipitation in the 20 ppm sulfate ion solution after 24 hours. 2) In the quantification, the same proportion of the NP-10SM as the commercial product did not decrease a few quantities of the CHG in the 50 ppm sulfate ion solution. In the lower concentration of the NP-10SM, the quantity of CHG was decreased to 90% after 5 hours. In our hospital, therefore, we supplied 5% H-C containing the 7% NP-10SM for the 5% CHG.