Surface and Solution Properties of Amphiphilic Drug‐Nonionic Surfactant Systems

Abstract

AbstractA surface tension study was performed on mixed amphiphilic drug‐nonionic surfactant systems. The drugs used were adiphenine hydrochloride and nortriptyline hydrochloride whereas surfactants were ethoxylated sorbitan esters and polyethylene oxide–polypropylene oxide–polyethylene oxide triblocks. The critical micelle concentration (CMC) and CMCid (CMC at ideal mixing condition) values suggest nonideal and attractive interactions among the components. The micellar mole fraction values calculated using Rubingh's model indicate predominance of the nonionic surfactant in micelle formation. The mole fraction of surfactant in mixed monolayer values are greater than values, indicating a greater contribution of surfactant in monolayer formation. Thermodynamic parameters, viz. Gibbs energy of micellization , Gibbs energy of adsorption , and excess free energy of mixed micelles and monolayers were also evaluated. All these values suggest stable mixed micelle and mixed monolayer formation.