Influences of spray drying a coating liquid on the properties of coated films were investigated by using, three types of fluidized bed coaters. The top spray method with a conventional fluidized bed coater was ineffective in producing small amounts of coated particles for controlled drug release. Both a smooth surface of coated particles and a high adhesion efficiency were obtained by using the side spray method in a fluidized bed coater with a rotary disk. It is concluded that the concentration of coating materials in the liquid layer on coated particles plays an important role in determining the physical properties of the coating film.