Disclosed is a sustained release system that includes a polymer and a pharmaceutically active agent dispersed in the polymer. The agent is in granular or particulate form, and has a rate of release from the system that is limited primarily by the rate at which the agent dissolves from the granules into the polymer matrix. Advantageously, the polymer is permeable to the agent and is non-release-rate-limiting with respect to the rate of release of the agent from the polymer.