Molecular interactions of sodium salicylate in physiological media under the influence of electrolyte/non-electrolyte at different temperatures: Volumetric and acoustic study

Drug interactions in presence of co-solute in aqueous solution have always created an interest in the mind of chemists. The physical properties give an idea of types of interactions taking place in aqueous solution. Volumetric and compressibility are the important physical properties. Keeping this in mind we have measured the densities ( ρ ) and speeds of sound ( u ) of sodium salicylate (NaSl) drug (0.01–0.1) mol·kg−1 in 0.06 mol·kg−1 aqueous sodium chloride solution and 0.06 mol·kg−1 myo-inositol as a function of temperature at T = (288.15, 298.15 and 308.15) K and atmospheric pressure. These values have been used to estimate the apparent molar volume of solute ( V ϕ ) , apparent molar isentropic compressibility ( κ s ) of solution and apparent molar isentropic compressibility ( κ ϕ ) of solute. The limiting apparent molar expansivity ( E ϕ 0 ) of solute and coefficient of thermal expansion ( α ∗ ) of sodium salicylate in aqueous binary and ternary solutions have also been obtained. Limiting values of apparent molar volume of solute ( V ϕ 0 ) and apparent molar compressibility of solute ( κ ϕ 0 ) were obtained from the plots V ϕ and κ ϕ as a function of molality and have been utilized in obtaining transfer volumes ( Δ tr V ϕ 0 ) and transfer compressibilities ( Δ tr κ ϕ 0 ) of sodium salicylate from water to 0.06 mol·kg−1 aqueous solutions of sodium chloride and myo-inositol at different temperatures. The co-sphere overlap model is used to interpret the values of ( Δ tr V ϕ 0 ) and ( Δ tr κ ϕ 0 ) . The Helper’s constant has been obtained. It indicates structure making ability of sodium salicylate in aqueous as well as in 0.06 mol·kg−1 aqueous sodium chloride and 0.06 mol·kg−1 aqueous myo-inositol solutions. The results obtained have been interpreted in terms of various interactions taking place among solute and solvent molecules.