Application of tumbling melt granulation method to prepare controlled-release beads by coating with mixture of functional non-meltable and meltable materials.

A new coating method for use in preparing controlled-release beads was developed by modifying the tumbling melt granulation technique. The dissolution rate of the drug from the beads was controlled by coating the mixture of meltable and non-meltable materials by heating in a centrifugal fluidizing granulator without using any solvent. In experiments using talc as the non-meltable material, the resultant beads showed the sufficient ability to suppress the dissolution of the drug and no change in the dissolution characteristics by wetting agent and in a stability test at high temperature. Using functional polymer as the non-meltable material, the controlled-release beads with various dissolution characteristics could be prepared: entero-soluble-release beads using entero-soluble polymer, and zero-order-release beads using hydrophilic gel-forming agent and talc.