Abstract: In masking particles comprising a drug-containing particle containing a drug of a salt with an acid and containing a carbonate, the drug-containing particle being coated with a coating layer containing a water-insoluble polymer, drug release in the oral cavity and pharynx is sufficiently suppressed, the drug is rapidly released after swallowing, and the release suppression time of the drug is easily controlled. The drug-containing particle may comprise a core particle and an interlayer on the core particle, and the core particle may contain the drug of a salt with an acid, and the interlayer contains the carbonate, or the core particle may contain the carbonate, and the interlayer may contain the drug of a salt with an acid.

Abstract: Masking particles which comprise a drug-containing particle containing a drug, an acid, and a carbonate, the drug-containing particle being coated with a coating layer containing a water-insoluble polymer sufficiently suppress drug release in the oral cavity and pharynx, rapidly release a drug after swallowing, and easily control the release suppression time of a drug. The acid may be at least one organic acid. The carbonate may be at least one water-soluble carbonate. Oral pharmaceutical compositions include tablets, granules, fine granules, powders.