Investigation on molecular interactions of antibiotics in alcohols using volumetric and acoustic studies at different temperatures

The density and sound velocity for pure alcohols (methanol, ethanol, iso-propanol and n-butanol) and molal solutions of nitroimidazoles (metronidazole (MNZ) and dimetridazole (DMZ) have been measured at different temperatures (293.15-313.15 K). Different volumetric and acoustical parameters like apparent molar volume (Vϕ), partial molar volume (V˚ϕ), apparent molar isentropic compressibility (Kϕ), partial molar isentropic compressibility (K˚ϕ), hydration number (nH), acoustic impedance (Z) and intermolecular free length (Lf) of antibiotic solutions were calculated from the experimental values of density and sound velocity. The derived values have been used to explore the solute-solute and solute-solvent interactions. The Vϕ values are positive and Kϕ values are negative in both antibiotics, indicative of strong solute-solvent interactions and closely packed structure of antibiotics in alcohols. The decreasing trend of Lf with increasing antibiotic concentration shows the presence of strong intermolecular interactions in solutions.