Solubility determination and thermodynamic modelling of gliclazide in five binary solvent mixtures

The solubility of gliclazide in five different binary solvent mixtures , (i.e. acetone-water, tetrahydrofuran-water, N , N -dimethylformamide-water, acetone-ethanol, and chloroform-ethanol) was measured in the temperature rang 278.15–318.15 K and at atmospheric pressure by a gravimetric method. The results show that the solubility of gliclazide increases with an increase in temperature and an increase in the mole fraction of nonpolar aprotic solvent . The combined nearly ideal solvent / Redlish-Kister (CNIBS/R-K) model, modified Jouyban-Acree model, non-random two-liquid (NRTL) model, and the Wilson model were selected to correct the solubility data. It was found that, solvent polarity has a critical effect on the solubility of gliclazide. The CNIBS/R-K model, with maximum RAD and RMSD values of 0.0540 and 0.000131, respectively, was found to be the best-fitting model for solubility data correction in the selected binary solvent mixtures. RAD values of all the selected thermodynamic models were <0.0806, that is, these equations produced well fitted results for the solubility data of gliclazide. These experimental data are of great significance for investigation of the crystallization process of gliclazide.