Temperature-Dependent Physicochemical Properties of Di and Tri-Peptides of Glycine in Aqueous Myo-Inositol

Abstract The present study investigates the temperature-dependent physicochemical properties of glycylglycine and glycylglycylglycine in pure water and aqueous myo-inositol solutions of varying molal concentrations (0.05, 0.10, and 0.15 mol·kg–1) over the temperature range 293.15–318.15 K under a constant pressure of 101.3 kPa. Measurements of density, ultrasonic velocity, and viscosity served as the basis for calculating a range of volumetric, acoustic, and viscometric parameters, such as apparent molar volume (Vϕ), partial molar volume at infinite dilution (Vϕ0), limiting apparent molar expansibility (Eϕ0), apparent molar isentropic compressibility (Kϕ,s0), transfer parameters, and viscosity B-coefficients. Analysis of these thermodynamic and transport properties enabled the assessment of the dominant molecular interactions between glycylglycine and myo-inositol, as well as between glycylglycylglycine and myo-inositol, in aqueous media. The collective findings indicate the prevalence of hydrophilic–hydrophilic interactions, demonstrating the cooperative role of inositol in enhancing solvation dynamics and the structuring of water molecules around the solutes.