Oral formulations masking the bitter taste of a drug having a bitter taste

Drugs having a bitter taste, for example, very bitter with a strong drug silodosin, foreign body sensation without without water can take, and the dissolution of being able to reproduce the effective blood concentration in the treatment of such dysuria associated with benign prostatic hyperplasia comprising the novel oral dosage formulations (especially, oral rapid disintegrating formulation) provides. The present invention is an agent having a bitter taste (e.g., silodosin) drug particles containing methyl methacrylate - a masking particles obtained by granulation or coated with a coating agent containing diethylaminoethyl methacrylate copolymer , methyl methacrylate - diethylaminoethyl copolymer content methacrylic acid, drugs having a bitter taste (e.g., silodosin) is 80 parts by weight to 400 parts by weight per 100 parts by weight, novel containing masking particles and said masking particles it relates an oral dosage formulations and the like.