Seeking to improve the dissolution rate profile of theophylline from coated theophylline granules, the authors incorporated various additives into a film-coating mixture of Et cellulose and di-Bu sebacate. The additives studied were propylene glycol, carrageenan, Me cellulose, hydroxypropyl cellulose, hydroxypropyl Me cellulose (HPMC), and theophylline powder. Of these additives, HPMC altered the granule's dissolution profile most effectively. The release rate of theophylline from the coated granules could be adjusted by varying the amount of HPMC added to the Et cellulose-diBu sebacate dispersion. When a sufficient amount of HPMC was added to the dispersion, all of the theophylline was released within 7 h.