PREPARATION AND CHARACTERIZATION OF SOLID DISPERSIONS OF CARVEDILOL WITH POLOXAMER 188

Abstract

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 poloxamer 188 were prepared by fusion 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, DSC thermograms and SEM photographs, carvedilol was in the amorphous form, which confirmed the better dissolution rate of solid dispersions. FTIR results proved no chemical interaction between carvedilol and poloxamer 188. SEM images showed a novel morphology of solid dispersion compared with pure drug. The solid dispersion was stable under accelerated storage conditions.