Solubility correlation and thermodynamic analysis of solution of tylosin tartrate in methanol + tetrahydrofuran or acetone) mixtures

The solubility data of tylosin tartrate in methanol + (tetrahydrofuran or acetone) mixtures was determined at atmospheric pressure by a gravimetric method over temperature range of 293.15-323.15 K. The experimental results indicated that solubility of tylosin tartrate increases with increasing temperature in selected solvents, and that solubility of tylosin tartrate first increases, reaches a maximum and then decreases with increasing the mass fraction of methanol in the binary solvent mixtures at constant temperature. Solubility data were correlated by Apelblat model and λh model, the results showed that the two models agreed well with the experimental data, and the λh model is a little more accurate than Apelblat model from R2 and the total root-mean-square deviations (RMSD). The molar enthalpy (△ Ho) and entropy (△ So) for tylosin tartrate dissolution in solvent mixtures were calculated with solubility data using van't Hoff equation, dissolution process of tylosin tartrate was endothermic process, △ Ho > 0 and was an entropy-drives process △ So > 0. Therefore, the experimental data and model parameters would provide essential support for industrial design and further theoretical studies.