The present invention provides a controlled release oral pharmaceutical composition having a therapeutically effective amount of one or more pharmacologically active agent having low bioavailability； one or more solubilizers； one or more biocompatible swelling agents； and a swelling enhancer. The swelling agent, in combination with swelling enhancer, swells in the presence of water in gastric fluid such that the size of the dosage form is sufficiently increased to provide retention of the dosage form in the stomach of a patient, which gradually erodes within the gastrointestinal tract over a prolonged time period.
