Micellization behavior of the amphiphilic drug promethazine hydrochloride with 1-decyl-3-methylimidazolium chloride and its thermodynamic characteristics

The micellization behavior of promethazine hydrochloride (PMT) with 1-decyl-3-methylimidazolium hydrochloride, [C(10)mim] [Cl], at different temperatures was investigated by using electrical conductivity. The system thermodynamic properties were also studied by calculating various thermodynamic parameters (viz., the standard Gibbs energy change, Delta G degrees(m) the standard enthalpy change, Delta H degrees(m), the standard entropy change, Delta S degrees(m)), that favor the micellization in binary mixtures of PMT-[C(10)mim][Cl] compared with the pure counterparts, at two mole fractions of PMT. The synergistic interaction is examined using Regular Solution Theory for PMT-[C(10)mim] [Cl] binary mixtures, through the interaction parameter (beta) and activity coefficient (f(1) and f(2)) values. The synergism is also revealed in the deviations in the critical micelle concentration (cmc) from the ideal critical micelle concentration (cmc*) and micellar mole fraction (X-1) from ideal micellar mole fraction (X-1(ideal)) values. The value of excess free energy (Delta G(ex)) for alpha(1) = 0.6 at 308 K favor the better condition for the formation of the most stable and compact mixed micelles. (C) 2014 Elsevier B.V. All rights reserved.