(EN) The present invention relates to a controlled-release drug delivery system for oral administration and a composition for forming a controlled-release porous membrane employed in the system. The controlled-release drug delivery system for oral administration of the present invention comprises a core containing a pharmaceutically active ingredient; and a controlled-release porous membrane coated on the outer surface of the core comprising at least one film formation material selected from the group consisting of a cellulose based compound, polymethacrylate, an acetate based compound, polyamide, polyurethane and sulfonated polystyrene. The controlled-release drug delivery system for oral administration according to the present invention can provide an effective and consistent drug release in gastrointestinal tracts because the release rate of the drugs can be controlled. Also, the timing of drug release can be controlled by varying the thickness of the porous membrane, composition of the membrane material, amount of the plasticizer and amount of the vehicles. And, preparation of the controlled-release formulation becomes simple and cost-effective because a small amount of the porous membrane is coated on a conventional tablet or granule. In addition, since the membrane is highly stable, a controlled-release formulation for oral administration not affected by temperature or humidity can be produced in large quantities.
