Physico-Chemical Properties of Glycyrrhizic Acid in aqueous Media. V. Critical Micelle Concentration of Mixed Solutions of Glycyrrhizin and Sodium Cholate

Abstract

Critical micelle concentrations (cmc) of the mixed solutions of glycyrrhizin and sodium cholate were determined by the measurements of light absorption of aqueous iodine solution and solubility of yellow-OB as well as the measurements of surface tension. Critical micelle concentrations of the mixed solutions determined by these methods were relatively in good agreement with each other. The cmc increased with increasing the mol fraction of sodium cholate and pH. It was found that the cmc of mixed solutions and the composition of mixed micelles were in conformity with the theory of ideal mixing. The facts suggest that glycyrrhizin contributed effectively to the formation of mixed micelle. The mol fraction of glycyrrhizin in mixed micelle increased with decreasing pH.