Solubility and Apparent Oil/Water Partition Coefficient of Sulfamethazine / 中国药房

ABSTRACT

OBJECTIVE:To determine the equilibrium solubility and the apparent partition coefficient of sulfamethazine(SM2) in a series of phosphate buffer solutions of different pH so as to provide a basic study for the exploitation of SM2 preparation.METHODS:A series of buffer solutions of different pH were prepared.The apparent solubility was determined by saturation method;Ko/w was calculated with concentration ratio of SM2 in n-octanol and water phase after partition equilibrium.RESULTS:The maximum equilibrium solubility was 1.916 g?L-1 at pH 2 and 1.375 g?L-1 at pH 9,and the maximum of apparent partition coefficient was 3.9070 at pH 8.CONCLUSION:The equilibrium solubility and apparent partition coefficient of SM2 are correlated to pH of the medium.SM2 dissolved preferably when pH6.8,but SM2 was more distributed in the lipid phase and easier to be absorbed by body when pH=3～8.