Abstract: Sustained release pharmaceutical dosage forms include a core containing at least one swellable, water soluble, pH independent polymer and a first water insoluble, pH independent polymer, and a permeable membrane coat containing a swellable, water soluble, pH independent polymer and a second water insoluble, pH independent polymer. The sustained release pharmaceutical dosage forms are free of osmagens and/or diluents and demonstrate similar release characteristics as compared to known sustained release formulations that contain osmagens and/or diluents. Additionally, the release profile for the sustained release pharmaceutical dosage forms is resistant to dose dumping in the presence of alcohol.