PREPARATION AND CHARACTERIZATION OF ETHYLCELLULOSE-WALLED THEOPHYLLINE MICROCAPSULES USING THE EMULSION-SOLVENT EVAPORATION TECHNIQUE

Ethylcellulose microcapsules containing theophylline are prepared by e mulsification of a organic ethylcellulose solution in a oil phase cont aining a surfactant. The preparation is based on dispersion of acetone containing the drug in liquid paraffin. Tween 80 was used as a disper sing agent. Good reproducibility in microcapsule preparation was obser ved. The microcapsules obtained were uniform and free-flowing particle s. The type of the stirring-manner (propella - and magnet - stirring), and the drug to polymer ratios have an important influence on the in vitro dissolution and release of theophylline from microcapsules.