Preparation and characterization of solid dispersions of carvedilol with PVP K30

Solid dispersions in water-soluble carriers have attracted considerable interest as a means of improving the dissolution rate, and hence possibly bioavailability, of a range of hydrophobic drugs. The poor solubility of carvedilol leads to poor dissolution and hence variation in bioavailability. The purpose of the present investigation was to increase the solubility and dissolution rate of carvedilol for enhancement of oral bioavailability. In the present investigation solid dispersions with PVP K30 were prepared by solvent evaporation method. The physical mixture and solid dispersion(s) were characterized for drug-carrier interaction, drug content, solubility and dissolution rate. The solubility of drug increased with increasing polymer concentration. The dissolution rate was substantially improved for carvedilol from its solid dispersion compared with pure drug and physical mixture. As indicated from X-ray diffraction pattern and DSC thermograms carvedilol was in the amorphous form, which confirmed the better dissolution rate of solid dispersions. The solid dispersion was stable under accelerated storage conditions. The solid dispersion technique with PVP K30 as a carrier provides a promising way to enhance the solubility and dissolution rate of carvedilol.