Enhancement of Dissolution Rate of Glimepiride using Solid Dispersions with Polyvinylpyrrolidone K 90

Abstract:

The aim of the present study was to enhance the dissolution rate of glimepiride using its solid dispersions (SDs) with polyvinylpyrrolidone K 90. The phase solubility behavior of glimepiride in presence of various concentrations of polyvinylpyrrolidone K 90 in phosphate buffer pH 7.4 was obtained at 37oC. The solubility of glimepiride increased with increase in amount of polyvinylpyrrolidone K 90 in buffer pH 7.4. Gibbs free energy (ÄGo ) values were all tr negative. The solid dispersions of glimepiride with polyvinylpyrrolidone K 90 were prepared at 1:1, 1:3 and 1:5 (glimepiride: PVPK 90) ratio by kneading method. Evaluation of the properties of the solid dispersions was performed by using dissolution, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) studies. The solid dispersions of glimepiride with polyvinylpyrrolidone K 90 exhibited enhanced dissolution rate of glimepiride. The mean dissolution time (MDT) of glimepiride decreases significantly in solid dispersions. The Fourier-transform infrared spectroscopic studies showed formation of intermolecular hydrogen bonding between glimepiride and polyvinylpyrrolidone K 90. The X-ray diffraction studies indicated the partially amorphous state of glimepiride in SD of glimepiride with polyvinylpyrrolidone K 90.

Key words: Glimepiride, polyvinylpyrrolidone K 90, solubility, dissolution rate