Preparation of Controlled Release Particles by Suspension Spray Method Using Fluidized Bed Coater with Rotary Disk

Preliminary study for preparation of controlled release particles was carried out by using a fluidized bed coater with a rotary disk. Two types of controlled release particles, particles coated by ethylcellulose film and particles consisting of drug-wax mixture layer, were prepared. Physical properties of controlled release particles prepared by both powder spray method and suspension spray method were measured. The release rate of drug from the coated particles decreased with increasing thickness of coated film. It was necessary to heat the particles for production of controlled release particles consisting of drug-wax mixture layer. The release behavior of drug was almost similar for those prepared by powder spray method and suspension spray method. Suspension spray method is advantageous in increasing loading volume and drying capacity.