Effects of coating conditions on release profiles of controlled release granules coated with water insoluble polymer

摘要

Capsule-type controlled release granules coated by water insoluble polymer were prepared, in which metominostrobin was used as a model agrochemical. The effects on release profiles of coating processes, and content of polymer were evaluated with equal amounts of the polymer. For coating, the release rate of metominostrobin from the granules coated with the polymer (solid content: 50%) by the dropping process [D-1] was faster than that from the granules coated by the fluidized bed process [F-1]. Forthe solid content, the order of release rate from the granules was F-1>F-2 which was coated with the aqueous dispersion containing 5% solid content of the polymer by the fluidized bed process. Superposition analysis on the release rates revealed that the difference in release mechanisms was dependent on the solid content of the polymer but not on coating processes. Observation by SEM suggested that the release rate and release mechanism could correlate to each other and be related with the surface structure of the granules.