Volumetric, acoustic and viscometric studies of solute-solute and solute-solvent interactions of isoniazid in aqueous-glucose/sucrose solutions at temperatures from 293.15 K to 318.15 K

Abstract

The densities, ρ, ultrasonic speeds, u and viscosities, η of the drug isoniazid in water and in aqueous–d-glucose/d-sucrose (5 wt% and 10 wt% glucose/sucrose in water) solvents were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and at atmospheric pressure. The ρ, u and η data have been used to calculate apparent molar volumes, Vϕ, limiting apparent molar volumes, Vϕ∘, apparent molar compressibilities, Ks,ϕ, limiting apparent molar compressibilities, Ks,ϕ∘, transfer volumes, Vϕ,tr∘ and transfer compressibilities, Ks,ϕ,tr∘. The viscosity data have been used to determine Falkenhagen Coefficients, A and Jones-Dole coefficients, B. The calculated parameters have been discussed in terms of various solute-solute and solute-solvent interactions prevailing in these solutions. The structure making/breaking ability of isoniazid in these solutions has been examined by using the sign of dB/dT. Furthermore, the Gibbs energies of activation of viscous flow per mole of solvent, Δμ1∘# and per mole of solute, Δμ2∘#, enthalpies, ΔH∘ and entropies, ΔSo of activation of viscous flow, were also calculated and discussed in terms of transition state theory.