Interaction of antibacterial drug ampicillin with glycine and its dipeptides analyzed by volumetric and acoustic methods at different temperatures

The interactions of glycine (gly), glycylglycine (gly-gly), glycylleucine (gly-leu) with drug ampicillin as a function of temperature have been investigated by combination of volumetric and acoustic methods. Densities and speeds of sound of glycine and its dipeptides in aqueous solutions of ampicillin have been measured at T = (305.15, 310.15 and 315.15) K and atmospheric pressure. The apparent molar volume (Vϕ), the partial molar volume (Vϕ0) and standard partial molar volumes of transfer (ΔVϕ0) for glycine and its dipeptides from water to aqueous ampicillin solutions have been calculated from density data. Partial molar adiabatic compressibility (Kϕ) and partial molar adiabatic compressibility of transfer (ΔKϕ0) have been calculated from speed of sound data. The pair and triplet interaction coefficient have been calculated from both the properties. The absorption spectra have also been recorded for present mixtures with the help of UV–visible spectrophotometer. The results have been explained on the basis of competing patterns of interactions of co-solvents and the solute.

► Densities and speeds of sound of glycine and its dipeptides in aqueous ampicillin.
► Ampicillin is an antibacterial drug is a beta lactam antibiotic.
► Partial molar volumes and compressibility of transfer.
► Transfer volume data have been used to calculate the pair and triplet interactions.
► Solute–solute and solute–solvent interactions and the structural changes of the solutes.