Drug Release from Ammonio-Methacrylate-Coated Diltiazem Particles: Influence of the Reservoir on Membrane Behavior

Drug-layered sugar spheres 15, 45, and 64% potent were made such that each had the same particle size distribution. The particles were coated to the same coat thickness with an ammonio polymethacrylate formulation, and drug release was measured in two media. The products exhibited a sigmoidal release pattern, where a lag time was followed by relatively rapid drug release. Lag time depended on the applied polymer amount, the media used, and the sugar content, where an increase in sugar content caused greater expansion before drug release. Lag times were related to expansion. Expansion of coated sugar spheres was measured.