Cloud Point Phenomenon in Amphiphilic Drug Solutions

Abstract

We report here the cloud point (CP) phenomenon in amphiphilic drug amitriptyline (AMT) solutions. We have investigated the influence of electrolytes on the micellar behavior of AMT by using CP and dye solubilization techniques. The CP was found to considerably decrease with increasing pH due to a reduction in electrical repulsion between AMT micelles. It increased on addition of electrolyte due to an increase in electrical repulsion resulting from an increase in the cationic AMT micelle size. The binding effect of anionic counterions was in the order: Br- > Cl- > F-. The effect of cations was insignificant compared to anions.