Probing interactions and hydration behaviour of drug sodium salicylate in aqueous solutions of D-xylose/L-arabinose: Volumetric, acoustic and viscometric approaches

Abstract

The solute–solute and solute–solvent interactions of drug sodium salicylate in aqueous-carbohydrate solutions are investigated using experimentally measured densities, ρ, ultrasonic speeds, u and viscosities, η of the drug sodium salicylate in water and in aqueous−D-xylose/L-arabinose (5% and 10% D-xylose/L-arabinose in water, w/w) solvents at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and at atmospheric pressure. The ρ, u and η data were used to calculate the apparent molar volumes, Vϕ, limiting apparent molar volumes, Vϕ°, limiting apparent molar expansibilities, Eϕ°, apparent molar compressibilities, Ks,ϕ, limiting apparent molar compressibilities, Ks,ϕ° along with the transfer volumes, Vϕ,tr° and transfer compressibilities, Ks,ϕ,tr°. Furthermore, Falkenhagen coefficient A, Jones-Dole coefficient B, free energy of activation of viscous flow per mole of solvent, Δμ1°# and per mole of solute, Δμ2°#, enthalpies, ΔH°# and entropies, ΔS°#of activation of viscous flow were obtained from the viscosity data. The observed trends in these properties as function of temperature and composition were analysed in terms of molecular interactions amongst the solute and solvent molecules. The results are discussed in terms of hydrophilic-hydrophilic and hydrophilic-hydrophobic interactions in these systems along with the structure breaking/making ability of the drug.