The mixed micellization behavior of surface active ionic liquids (SAILs), 1-dodecyl-3-methylimidazolium chloride, [C(12)mim][Cl], and 1-tetradecyl-3-methylimidazolium chloride, [C(14)mim][Cl] with an amphiphilic drug amitriptyline hydrochloride (AMT) have been studied using surface tension and conductance. Interfacial parameters obtained from surface tension were beneficial in deciphering the phenomenon taking place at the interface. Critical micelle concentration (cmc), and various thermodynamic parameters were achieved from conductance. The negative values of Delta G(mic)degrees: and Delta G(ad)degrees: indicate the feasibility of the mixed micellization process. Rubingh and Motomura introduced theoretical model for micellar interaction parameter (beta(m)) have been examined to investigate the interactions between AMT and the SAILs. (C) 2018 Elsevier B.V. All rights reserved.