Clouding and thermodynamic behavior of the triton X-100 + metformin hydrochloride drug mixture: Investigation of the impacts of potassium salts

Abstract

The cloud point (CP) of aqueous triton X-100 (TX-100) and metformin hydrochloride (MNH) mixture was investigated in the attendance of various inorganic salts (KCl, KHSO4, K2SO4, and K3PO4) media. TX-100 concentration for CP measurement was chosen well above the critical micelle concentration value of TX-100. The values of CP decrease as the electrolyte’s concentration raises, turning the clear solution cloudy. The reason of the reducing CP is the enhanced aggregation. Thermodynamic variables of the clouding process (standard free energy (ΔG0c), standard enthalpy (ΔH0c), and standard entropy (ΔSco)) were determined at CP. The Gibbs free energy (ΔG0c) values were positive but dropped as the additive (inorganic electrolytes) concentrations increased. This result demonstrated that the TX-100 + MNH mixture's phase partition was thermodynamically unfavoured, and the percentage of its non-spontaneity reduced as the electrolytes concentration enhanced. The values of enthalpy (ΔH0c) and entropy (ΔSco) for the phase separation were achieved negative at lower electrolyte concentrations and positive at higher contents. The ΔH0c and ΔSco values suggest that hydrophobic and electrostatic interactions are the primary forces amongst TX-100 and MNH. Here, the intrinsic enthalpy gain (ΔH0*c) and the compensation temperature (Tc) are as well computed and explained.