Abstract
The aim of present investigation was to determine the mole fraction solubility of a poorly water soluble antidiabetic drug gliclazide (GLZ) in mono-solvents and various Transcutol + water co-solvent mixtures at (298.15 to 333.15) K. The experimental solubility of GLZ was measured by shake flask method and resulting data was correlated with the modified Apelblat model at each temperature studied. Good correlation was observed between the experimental data of GLZ and calculated one with absolute relative deviation in the range of (0.050 to 5.680) %. The correlation coefficients were observed in the range of 0.9966 to 0.9995 which indicated good fitting of experimental solubility data. The lowest mole fraction solubility of GLZ was observed in pure water (1.9 x 10(-6) at 298.15 K) whereas the highest one was observed in pure Transcutol (11.9 x 10(-3) at 298.15 K). The enthalpies and entropies for GLZ dissolution were observed as positive values in the range of (15.742 to 40.551) kJ mol(-1) and (52.801 to 121.721) J mol(-1) K-1, respectively in all sample matrices. These results of thermodynamic parameters indicated that the dissolution of GLZ is endothermic and an entropy-driven process. Based on current solubility data, GLZ was considered as practically insoluble (poorly soluble) in pure water and soluble in Transcutol. These preliminary studies indicated that Transcutol could be used as a co-solvent for solubility enhancement of GLZ which could help in preformulation studies and formulation development of GLZ.