SUSTAINED RELEASE PHARMACEUTICAL PREPARATION

摘要

The present invention pertains to a sustained release drug delivery system which comprises a core of active ingredient, an enteric coating, a second coating of active ingredient and lastly a readily gastric-soluble protective coating. In another embodiment, the sustained release drug delivery system comprises a core of active ingredient, an enteric coating; a second coating of active ingredient; a second enteric coating and a third coating of active ingredient. The sustained release dosage form of this invention is useful fo r pharmaceutically active ingredients that have limited aqueous solubility, especially phenytoin sodium, and other pH dependent soluble drugs.