Thermodynamic Studies of Molecular Interactions between Local Anesthetical Drug (Procaine Hydrochloride) and Amino Acid (Glycine) in Aqueous Solutions at T (=288.15–318.15 K)

Abstract

The experimental measurements of density (ρ) and speed of sound (c) for the local anesthetical drug procaine hydrochloride (PC·HCl) in aqueous and aqueous (0.0493, 0.1008, and 0.1487 mol·kg^–1) glycine solutions at different temperatures (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, and 318.15 K) are reported. Further, ρ and c data were used to calculate apparent molar volume of solute (V_ϕ), apparent molar volume of solute at infinite dilution (V_ϕ⁰), coefficient of thermal expansion of solution (α), apparent molar expansibility of solute (E_ϕ), apparent molar expansibility of solute at infinite dilution (E_ϕ⁰), isentropic compressibility of solution (κ_s), apparent molar isentropic compressibility of solute (K_ϕ,S), and apparent molar isentropic compressibility of solute at infinite dilution (K_ϕ,S⁰). The transfer partial molar volume (Δ_trV_ϕ⁰) of PC·HCl from water to aqueous glycine solutions is estimated. Moreover, UV–visible spectroscopic studies were also conducted to confirm the presence of interactions in the studied systems. The findings are interpreted in the context of molecular interactions in PC·HCl–glycine through the understating of solute–solute and solute–solvent interactions.