The colloidal properties of chlorhexidine and its interaction with some macromolecules

Abstract

Abstract Surface tension, conductivity and dye solubilization experiments show that, in aqueous solution, chlorhexidine diacetate forms micelles and has a molar critical micellar concentration (CMC) of 0·010–0·011 at 25°. Similarly, the digluconate salt has a molar CMC of 0·0066. Above its CMC, the freely soluble digluconate salt solubilizes the less soluble diacetate salt. The formation of micelles does not affect the rate of hydrolysis of chlorhexidine to p-chloroaniline. It is suggested that the micelles formed by chlorhexidine resemble those formed by many dyes rather than those of colloidal surfactants. Equilibrium dialysis experiments show that 1·0 and 3·0% polysorbate 80 inactivates 37·5 and 70·0% respectively of the chlorhexidine in a 0·10% solution of the diacetate salt.