Impacts of several salts on the clouding development, nature of interactions and associated physico-chemical variables of mixture of promethazine hydrochloride and conventional nonionic surfactant

Abstract

Herein, in the presence of electrolytes, the cloud points (CPs) of the mixture of a conventional uncharged amphiphile (triton X-100 (TX-100)) and promethazine hydrochloride (PMH; phenothiazine medicine) were measured and explained in great details. The CP values of the employed surfactant + PMH system were reduced with enhancing salts contents (NaCl, Na₂SO₄, NH₄Cl, and (NH₄)₂SO₄)), while the CP values of the study system followed the trend: Na₂SO₄ < NaCl and (NH₄)₂SO₄ < NH₄Cl. The different thermodynamic parameters of phase separation, including standard free energy (ΔG⁰_c), enthalpy (ΔH⁰_c), and entropy (ΔS⁰_c) changes were also calculated and discussed elaborately. The values of free energy change (ΔG⁰_c) were obtained to be positive, indicating that the clouding phenomena are non-spontaneous. Different transfer properties (free energy (ΔG⁰_c.t), enthalpy (ΔH⁰_c,t), and entropy (ΔS⁰_c,t) of transfer), intrinsic enthalpy gain (ΔH⁰,*_c) and compensation temperature (T_c) of the inspected system have also been assessed and discussed.

Graphical Abstract

Keywords:

• PMH drug
• TX-100
• solubility
• cloud point (CP)
• interaction forces
• thermodynamics

Additional information

Funding

The Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, Saudi Arabia has funded this project, under grant no. (KEP-38-130-42).