An Approach for Improvement of the Dissolution Rate of Gliclazide

Gliclazide is an anti-diabetic drug that is poorly soluble in water. This paper describes an approach to improve the dissolution rate of gliclazide by using solid dispersions (SDs) in polyethylene glycol 4000 (PEG 4000). The phase-solubility behavior of gliclazide in the presence of various concentrations of PEG 4000 in 0.1 N HCl at 37 degrees C was obtained. The solubility of gliclazide increased with increasing amounts of PEG 4000 in water. The Gibbs free energy (Delta G(tr degrees)) values were all negative. The solid dispersions were prepared with a solvent-melting method using different concentrations of PEG 4000. X-ray diffraction, infrared spectroscopy, and DSC were used to examine the physicochemical characteristics of solid dispersions of gliclazide and PEG. The dissolution rate of gliclazide in SDs with PEG 4000 was enhanced. The FTIR spectroscopic studies showed the presence of intermolecular hydrogen bonding between gliclazide and PEG 4000 in the solid state. The DSC and XRD studies indicate the amorphous and microcrystalline states of gliclazide in SDs with PEG 4000.