The timed-release pharmaceutical preparation of the invention is characterized by having a core containing a drug and a water-swellable substance, and a film containing a water-insoluble polymer, a plasticizer, and a water-insoluble filler, the core being coated with the film.With the timed-release pharmaceutical preparation of the present invention, the drug-release-initiation time and the drug release rate after the initiation of drug release can be controlled as desired.
