Insight into the solute–solute and solute–solvent interactions of pyridoxine hydrochloride in l -asparagine/ l -histidine/ l -arginine + water solvents by means of physicochemical methods at different temperatures

Thermophysical properties, which reflect the nature of solute–solute and solute–solvent interactions of drugs with amino acids, are investigated using experimentally measured values. The densities and speeds of sound of pyridoxine hydrochloride in l-asparagine/l-histidine/l-arginine + water solvents (1% and 2% l-asparagine/l-histidine/l-arginine in water, w/w) were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15 K) and at atmospheric pressure. The experimental density data have been used to calculate the apparent molar volume, limiting apparent molar volume, and transfer volume. The speed of sound data have been used to calculate various thermo-acoustical parameters, like apparent molar compressibility, limiting apparent molar compressibility, and transfer compressibility have been evaluated. These parameters have been deliberated in light of solute–solute and solute–solvent interactions prevailing in these solutions and their variations are utilised to portray the basic picture of the molecular interactions happening in these systems.