Spray-dried powder was coated in a fluidized bed coater with Wurster
insert. Coating material consisted of a 10 g/100 g solution of
hydroxypropyl cellulose (HPC), hydrated overnight. The inlet air
temperature was 60, 70 or 80 C and the coating solution feed rate
was 7 or 10 mL/min. The product temperature was in a range of 41,
50 or 63 C, respectively. Atomizing air pressure was adjusted along
the trials to maintain a good fluidization of the bed.