Particle coating is of increasing interest in the Pharmaceutical Industry, with more and more manufacturers moving towards production of tablets with layers of coating. When a tablet is coated with a drug, the amount of coating that each tablet possesses becomes very critical, as it constitutes the total dosage. The amount and consistency of drug coated on the tablet depends on the dynamics of the tablet in the vicinity of the spray zone.;The objective of this work was to study the dynamics of particle motion (large placebo tablets, 8mm diameter and sphericity factor, &phis; ≠ 1) in the vicinity of the spray zone of a semi-circular Wurster bed coater. A novel method of computer based video imaging was used to measure the velocity and voidage profiles in the draft tube region of the semi-circular fluidized bed coater. Continuous and pulse coating runs were performed to study the variation in coating consistency. This variation was explained in-terms of coating-per-pass variation and the cycle time variation. Inserts were used to alter the voidage profile around the spray nozzle and the coating runs were used to study their effect on the coating consistency. (Abstract shortened by UMI.)
