Formulation and Evaluation of Sustained Release Solid Dispersed Nifedipine Microcapsules

Conventional drug delivery system for treating the angina and hypertension are not much effective as the drug do not reach the site of action in appropriate amounts. Thus potent and guarded therapy of this angina and hypertension disorder using specific drug delivery system is a challenging task to the pharmaceutical professionals. The study was aimed at increase the solubility of poorly soluble drug nifedipine and formulating it in sustained release dosage form. Solid dispersion of drug was prepared using Poly vinyl pyrrolidone (PVP) as inert hydrophilic carriers by solvent evaporation technique. A 17-fold increase in dissolution rate of nifedipine was observed with solid dispersion prepared with PVP (K30). Sustained release microcapsules of nifedipine were formulated using Eudragit RS 100 as a polymer, acetone as polymer solvent for Eudragit RS100, N-hexane as a non-solvent, liquid paraffin vehicle, with solid dispersion of nifedipine as core by emulsion solvent evaporation method and modified emulsion solvent evaporation method. Microcapsules from all the batches were found to discrete, spherical and free flowing and % entrapment efficiency was found to be in range of 96.01% to 97.87%. All the batches of microcapsules showed sustained release curve in pH 7.4 phosphate buffer up to 12hours with maximum release up to 97.22% after 12hrs was found to be in B2. SEM studies of the microcapsules showed the surface topography states that prepared microspheres were spherical in shape. Shiny and uniform covered surface with polymer. Keywords: Nifedipine, Poly vinyl pyrrolidone, Solid dispersion, Microcapsules, Emulsion solvent evaporation method