Phase separation and aggregation phenomena of TX-100 and promethazine hydrochloride mixture: Influences of monohydroxy organic compounds

Abstract

Clouding nature and thermodynamic characteristics of surfactant-drug systems are novel approaches to chemists, industrialists, and researchers due to the enormous applications of the such mixture in pharmaceutical as well as technological sectors. In this study, the phase separation, assembly formation, and thermodynamic properties of triton X-100 (TX-100) + promethazine hydrochloride (PMH) drug mixed system were investigated by means of cloud point (CP) measurement and UV–visible spectroscopic techniques. The influences of the monohydroxy alcohols (ethanol (EtOH), 1-propanol (1-PrOH), 2-propanol (2-PrOH), along with 2-methyl-1-propanol (iso-BuOH) on the clouding development of TX-100 + drug mixed system have also been demonstrated. At lower concentrations of aqueous alcoholic media, the variation of CP with the enhancement of concentrations of alcohol were observed and increased CP values follow the trend: CPH2O+2-PrOH>CPH2O+EtOH>CPH2O+iso-BuOH>CPH2O+1-PrOH. The critical micelle concentration (CMC) of TX-100 + PMH mixture was found to be experienced an augmentation with the boost of the temperature. The obtained free energy values revealed the non-spontaneity of clouding and spontaneous aggregation of TX-100 + PMH mixture. The non-spontaneity of clouding of TX-100 + PMH mixture reduces with enhancement of concentrations of alcohols. The ΔHc0 and ΔSc0 values were found to be positive in almost all cases except at higher concentration of aq. 2-PrOH and iso-BuOH which disclosed the existence of hydrophobic as well as electrostatic interactions. The micellization of TX-100 + PMH mixed system in an aqueous medium was also accompanied by the hydrophobic interaction. The entropy-enthalpy compensation parameters of the clouding and micellization phenomenon were also elucidated through appropriate explanations.