Interactional behavior of saccharides/derivatives with amoxicillin drug in aqueous medium: Insights from volumetric, calorimetric and spectroscopic studies

Abstract

The physicochemical studies are significant in understanding the molecular interactions of saccharides and their derivatives with amoxicillin drug in aqueous solution. Therefore, the apparent molar volumes (V2,ϕ), and the limiting standard molar enthalpies of dilution (ΔdilH∞m) of saccharides and their derivatives in (0.001, 0.002, 0.003 and 0.004) mol·kg–1 aqueous solutions of amoxicillin were determined from the precise density, ρ and heat change, q measurements at (288.15, 298.15, 308.15 and 318.15) K under pressure, p = 0.1 MPa. The data were processed to obtain the corresponding transfer volumes (ΔtrV2∞) and enthalpies of dilution of transfer (ΔtΔdilH∞m) of solutes from water into aqueous solutions of amoxicillin. The volumetric expansion coefficients (∂V2∞/∂T)P, their second-order derivatives (∂2V2∞/∂T2)P and heat capacity change (∆dilC∞p,2,m) were also determined. Proton (1H) NMR spectra for mA = 0.02 mol·kg–1 saccharides/derivatives were also recorded in different molalities, mB = 0.001, 0.002, 0.003 and 0.004 mol·kg–1 of amoxicillin solution prepared in solvent {9:1 H2O + D2O}. The NMR results show that the Hc proton of amoxicillin has more activity (acidity) and it interacts more with the solute molecules (saccharide/derivative) than other protons of amoxicillin.