Abstract: 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 for pharmaceutically active ingredients that have limited aqueous solubility, especially phenytoin sodium, and other pH dependent soluble drugs.