Thermodynamic Studies of Binary and Ternary Mixtures of Duloxetine Hydrochloride and myo-Inositol: A Volumetric, Acoustic, and Viscometric Approach

The experimental data of densities (ρ), speed of sound (u) and viscosities (η) of myo-inositol (MI) in aqueous, duloxetine hydrochloride (DHCl) in aqueous and aqueous MI solution of different molal concentrations at seven temperatures in the range of (288.15–318.15) K has been reported. The thermophysical parameters like apparent molar volume (Vϕ) of solute, limiting apparent molar volume (Vϕ0), partial molar volume of transfer (ΔtrVϕ0), thermal expansion coefficient (α*), limiting apparent molar expansibilities (Eϕ0), isentropic compressibility (κS) of solution, apparent molar isentropic compression (Kϕ) of solute, limiting apparent molar isentropic compression of solute (Ks,ϕ0), partial molar compression of transfer (ΔtrKs,ϕ0), and hydration number (nH) were derived. The viscosity data have been used to determine the Falkenhagen coefficient A and Jones–Dole coefficient B on the basis of the Jones–Dole equation. By using the Nightingale, Benck, and Eyring equation, the free energy (ΔE20≠), enthalpy (ΔH20≠), and entropy of activation (ΔS20≠) were calculated. The solvation behavior of DHCl and MI in aqueous systems has been presented. Results are discussed in terms of solute–solute, solute–solvent, hydrophobic hydration, and H-bonding interactions in the studied systems. It is observed that DHCl behaves as a structure maker in both binary and ternary systems.