The aim of this study was to develop a microporous film for cellulose acetate (CA).A water-soluble polymer poly(ethylene glycol) (PEG) was used as a pore-forming agent to create micropores on CA films.The micropore-controlled release tablet continuously released drug more than 18 hours dependent of the level of the pore-forming agent in the coating film and the presence of lactose in the drug core.Both had a positive contribution on theophylline release from micropore-controlled release tablet.