Comparison of the Solubility and Dissolution Rate of Gliclazide-β-cyclodextrin Inclusion Complexes Prepared by Liquid/Liquid Extraction and Neutralization

The solid complexes of gliclazide and β-cyclodextrin were prepared by 2 methods, liquid/liquid extraction and neutralization. The phase-solubility diagram was used to calculate the stability constant of gliclazide and β-cyclodextrin. According to the molar stoichiometry, the complex of gliclazide with β-cyclodextrin was prepared following the 1:1 ratio. The interaction between gliclazide and β-cyclodextrin was analyzed by Fourier-transform infrared spectroscopy and differential scanning calorimetry. The dissolution rate of gliclazide from the complex made by liquid/liquid extraction was faster than those from neutralization method, physical mixtures and pure drug. The mean particle size of two complexes was smaller with a narrower size distribution than those of physical mixtures and β-cyclodextrin. The results indicate that liquid/liquid extraction method, as well as neutralization method, provides some signs of improvement in the solubility and dissolution rate of gliclazide.