Coating of Pharmaceutical Powders by Fluidized Bed Process. V. Agglomeration and Efficiency in the Coating with Aqueous Latices of Copoly(Ethyl Acrylate-Methyl Methacrylate-2-Hydroxyethyl Methacrylate)

The latices of copoly(ethyl acrylate-methyl methacrylate-2-hydroxyethyl methacrylate) exhibited a very low degree of agglomeration in the Wurster coating process, when the softening temperatures of their films were higher than inlet air temperature. This low agglomeration was due to their poor film-formability and, consequently, their low binding strength. Although this led to a low fixing efficiency of cosuspended solid particles, the coating efficiency of polymer itself remained high (about 90%). This low tendency of agglomeration was confirmed even in a coating of as fine a powder as 32-44 μm.