Effect of additives on mixed micellization of a phenothiazine drug promethazine hydrochloride and an ester-based pyridinium gemini surfactant

Promethazine hydrochloride (PMT) is a phenothiazine tranquilizer compound used as a sedative, analgesic, anticholinergic, antihistaminic and antipsychotic drug. The effect of various additives such as urea, glucose, glycine and sodium chloride (NaCl) on the mixed micellization of PMT and an ester-functionalized pyridinium gemini surfactant, (4, 4 '-(propane-1, 3-diyl) bis (1-(2-(hexadecanoyl oxy) ethyl) dipyridinium bromide (16-3-16), has been studied at a constant temperature using surface tension, conductivity and fluorescence techniques. The different micellar and interfacial parameters were evaluated which signify the non-ideal behavior of all mixed systems. The thermodynamic studies revealed that the micellization and adsorption processes are spontaneous with the latter being more prominent than the former since the values of standard Gibbs free energy of adsorption ) are more negative than those of standard Gibbs free energy of micellization (). Besides, the excess free energy change of micellization () was determined which also showed negative values. These studies are specially aimed to get a deep understanding of the effect of different biologically significant molecules on the mixed micellization of the PMT-(16-3-16) micellar systems so as to ensure the bioavailability and effectiveness of the drug. [GRAPHICS] .