Impacts of hydrotropes on clouding phenomena and physico-chemical parameters coupled with the triton X 100 & promethazine hydrochloride mixture
S. M. Rafiul Islam, Md. Rafikul Islam, Shamim Mahbub, Kamrul Hasan, Dileep Kumar, Javed Masood Khan, Anis Ahmad, Md. Anamul Hoque, Dipa Islam
Abstract
Phase separation behaviour of non-ionic surfactants (NISs)-drug in aq. hydrotropes (HDTs) has appealed interest to researcher over the decades. Herein, we have investigated clouding phenomenon and physico-chemical variables of TX 100 and promethazine hydrochloride (PMH) drug mixture in presence of different HDTs. Study reveals that cloud point (CP) is dependent on the concentration of HDTs in aqueous media. CP values increase with the augmentation of HDTs concentrations while CP values at nearly 100 mmol kg−1 HDTs follow the trend: CPH2O+4−AmB<CPH2O+Urea<CPH2O+NaBenz<CPH2O+NaSal. The positive standard Gibbs free energy (ΔGco) values signify the non-spontaneity of phase separation in all experimental cases. The positive values of ΔGco decrease with the augmentation of HDTs concentration. The observed ΔHco and ΔSco values are positive at low concentration of HDTs which demonstrates that hydrophobic interactions are the key forces of interaction among the studied ingredients. At high concentration of HDTs, the observed ΔHco and ΔSco values are found to be negative which demonstrates the enthalpy control process and the presence of exothermic interactions amongst TX 100, HDTs, and promethazine hydrochloride (PMH) drug in aqueous media. The thermodynamic properties of transfer, as well as enthalpy entropy compensation entities, were calculated and presented with proper clarification.