Influence of Solvents on Entrapment Efficiency and Drug Release rate of Propranolol Hydrochloride from Ethyl Cellulose Microcapsules

The influence of solubility of drug in the dispersed phase (Acetone: Water Mixtures) employed in the preparation on the entrapment efficiency and drug release from ethyl cellulose microcapsules was studied. Propranolol hydrochloride was used as core and microcapsules were prepared by an emulsion solvent evaporation method. All the solvents gave discrete, large sized, free flowing spherical microcapsules. The microcapsules were evaluated for size analysis, drug content, microencapsulation efficiency, wall thickness, drug release characteristics, influence of solvent employed on entrapment efficiency and Propranolol hydrochloride release from microcapsules, surface characteristics. Propranolol hydrochloride release from the microcapsules, followed zero order kinetics and influenced by the size of the microcapsules and the solvent employed in their preparation. The Propranolol hydrochloride release rate from the microcapsules was found to be decreased with increased proportion of water in the dispersed phase. Among the solvents employed acetone: water mixture (92.5% v/v : 7.5% v/v) was found to be more suitable for slow release of Propranolol hydrochloride from ethyl cellulose microcapsules.