Description

Extended release of solid dispersion of water soluble PHC was successively prepared by coevaporation with Eudragit RLPO in 1: 5 ratios. The sustainment of drug release was effected by drug-polymer ratio and method of preparation. The analysis by spectral techniques (FT-IR, FT-NMR) suggested possibility of hydrogen bonding. The results of DSC, XRD and SEM studies revealed the reduction in crystallinity of pure drug in solid dispersions as compared to their physical mixtures. The results of solubility studies were in accordance with the in vitro release profile and the order of sustainment of drug release was found in rank order of 0.1 N HCl (pH 1.2) double distilled water phosphate buffer (pH 7.4). The results of adsorption studies indicated that Eudragit RLPO had greater capacity to adsorb drug as compared to Eudragit RS100 in phosphate buffer (pH 7.4). The content homogeneity of PHC in granule was very high, as all the components in solid dispersions were dispersed and mixed on the molecule level. The dissolution of PHC, which is highly soluble in water, was markedly improved in the solid dispersions.