| abstract |
1. Technical Result Controlled release of an active compound. 2. Essence A controlled release bead comprises a core unit of a substantially water-soluble or water-swellable inert material, a first layer on the core unit of a substantially water-insoluble polymer, a second layer covering the first layer and containing an active ingredient, and the third layer on the second layer effective for controlled release of the active ingredient. The first layer is adapted to control water penetration into the core. 3. Field of Application Medicine. |