Encapsulation of Theophylline into Binary Blend of Ethylcellulose and Eudragit Microparticles: Development, Characterization and Kinetic Release

The objective of this study was to prepare and evaluate microparticles of Eudragit and Ethyl cellulose binaryblend loaded with theophylline for controlled release. Microparticles were prepared by Phase separation method.The method is quite simple, rapid, and economical and does not imply the use of toxic organic solvents. Solid,discrete, reproducible free flowing microparticles were obtained. The yield of the microparticles was up to 92%.More than 85% of the isolated microparticles were of particle size range of 325 to 455 μm. The obtained angleof repose, % carr’s index and tapped density values were well within the limits, indicating that preparedmicroparticles had smooth surface, free flowing and good packing properties. Scanning Electron Microscopyphotographs and calculated sphericity factor confirms that the prepared formulations are spherical in nature.Prepared microparticles were sTab. and compatible, as confirmed by DSC and FT-IR studies. The preparedformulations were quantitatively analyzed for the amount of encapsulated drug. It was observed that there is nosignificant release of the drug at gastric pH. The drug release was controlled more than 12 h. Intestinal drugrelease from microparticles was studied and compared with the release behavior of commercially available oralformulation Duralyn CR 400. The release kinetics followed different transport mechanisms