Conductometric and spectrofluorimetric characterization of the mixed micelles constituted by dodecyltrimethylammonium bromide and a tricyclic antidepressant drug in aqueous solution
ABSTRACT Conductivity and static fluorescence measurements have been carried out at 25 degreesC to study the monomeric and micellar phases of aqueous solutions of mixed micelles constituted by a conventional cationic surfactant, dodecyltrimethylammonium bromide (D(12)TAB), and a tricyclic antidepressant drug, amitriptyline hydrochloride (AMYTP), with aggregation properties. From conductivity data, the total mixed critical micelle concentration and the dissociation degree of the mixed micelle have been obtained, while fluorescence experiments allow for the determination of the total aggregation number, and the micropolarity of micellar inside. Furthermore, the partial contribution of each surfactant to the mixed micellization process, through their critical micelle concentrations and their aggregation numbers have been determined, as well. The solubilization of the drug in the mixed micelles has been also studied through the mass action model, by determining the association constant between the micelles and the drug. From these results, the use of the micelles studied in this work as potential models for vectors of antidepressant drugs of the amitriptyline family has been discussed. The theoretical aspects of the mixed micellization process have been also analyzed.
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ABSTRACT: The energetics of clouding in amphiphilic drugs, promazine hydrochloride and nortriptyline hydrochloride, in the presence of additives, such as alcohols and surfactants, are reported. The additives which assist in micellar growth like long-chain alcohols and cyclohexanol give negative ΔsH0 and TΔsS0 values, whereas cationic and nonionic surfactants increase the randomness in the system and hence TΔsS0 becomes positive. Anionic surfactants at low concentrations retard micellar growth and hence on increasing the concentration TΔsS0 values change from positive to negative.Journal of Chemical & Engineering Data 02/2009; 54:387-391. · 1.69 Impact Factor