Increase in Dissolution Rate of Simvastatin by Amorphous Solid Dispersion System with Hydroxypropylmethylcellulose Polymer

The objective of the present study was to prepare amorphous solid dispersion system simvastatin–hydroxypropylmethylcellulose (HPMC) to enhance the dissolution rate. Amorphous solid dispersion of simvastatin was prepared by solvent technique using HPMC as carrier with ratio of 1:1, 1:3 and 1:5 (w/w). Physicochemical properties of solid dispersions were investigated by X-ray powder diffraction, thermal analysis of differential scanning calorimetry (DSC) and scanning electron microscopy. The dissolution rate profile was performed at 37 ± 0.5 °C and 50 rpm in phosphate buffer solution (pH 7) containing 0,5% sodium laurylsulphate. Powder X-ray diffraction of solid dispersion system exhibited decrease in peak diffraction intensity of simvastatin when increasing the HPMC ratio in solid dispersion system. DSC thermogram of solid dispersion system showed the absence of endothermic peak of simvastatin. All the solid dispersion demonstrated faster dissolution rate in comparison with intact simvastatin and its physical mixture. The dissolution rate of simvastatin from solid dispersion increased with an increased ratio of HPMC polymer. The solid dispersion system of simvastatin with HPMC provide a promising way to improve its dissolution rate.