Self-association and mixed micellization of an amphiphilic antidepressant drug, 5[3-(Dimethylamino)propyl]-10,11-dihydro-5H-dibenz[bf]azepine hydrochloride and a nonionic surfactant, poly(ethylene glycol) t-octylphenyl ether: Evaluation of thermodynamics

In the continuation of our earlier work [1], the self-association, surface properties and mixed micellization of an amphiphilic tricyclic antidepressant drug, 5[3-(Dimethylamino)propyl]-10,11-dihydro-5H-dibenz[b,f]azepine hydrochloride (imipramine hydrochloride, IMP) and a non-ionic surfactant, poly(ethylene glycol) t-octylphenyl ether (Triton X-100) has been studied. In aqueous media, the surface and micellar properties (the critical micelle concentration (CMC), maximum surface excess concentration at the air/water interface (r(max)) and the minimum area per surfactant molecule at the air/water interface (A(min)) parameters, etc.) of IMP drug and Triton X-100 (independent as well as mixed) solutions are evaluated. The CMC as well as A(min) increase and the f r(max) decreases with increasing concentration (mole fraction) of the IMP. We also report the thermodynamics of IMP in absence and presence of surfactant. The Gibbs energies (viz., at air/water interface (G(min)((s))), the standard Gibbs energy change of micellization (Delta G(mic)(0)), the standard Gibbs energy change of adsorption (Delta G(ads)(0)), the excess free energy change of micellization (Delta G(ex)(m)) were evaluated. The aggregation number (N-agg) of IMP and Triton X-100 pure as well as their mixed systems has been studied. (C) 2018 Elsevier B.V. All rights reserved.