Acoustical studies of pharmaceutical excipients in binary solvent mixtures

Pharmaceutical excipients have gained a great importance due to their control of blood glucose level and sugar alternative. Thermodynamic methods provide an easy way for determination of solute-solute and solute-solvent interactions in solutions. Density and sound velocity for sugar alcohols have been measured in binary mixtures of Dimethyl Sulfoxide-Water at different percentage compositions (i.e. 10%-50%) at different temperatures. Density and sound velocity data have been used to calculate apparent molal volume, apparent molal isentropic compressibility, partial molal volume, partial molal isentropic compressibility, intermolecular free length, relative association, Rao's molar sound function and solvation number. Results have been discussed in terms of solvent-solvent, solute-solute and solvent-solute interactions. For all the systems studied, the density, sound velocity and apparent molal volume increase with increasing concentration of sugar alcohols which indicates the presence of solute-solvent interactions. The value of partial molal volume also increases with increasing temperature. The values of Sv are found positive while the values of apparent molal isentropic compressibility are negative which indicates the presence of solute-solvent interactions.