US Patent 7794750 Controlled-release formulations, method of manufacture, and use thereof

The present invention includes a controlled-release composition having a matrix. The matrix contains a pharmaceutically effective amount of an active agent or a pharmaceutically acceptable salt or solvate thereof, an ionic non-gelling matrix polymer, and a pH modifier. The ionic non-gelling matrix polymer is practically insoluble and unswellable at a first aqueous fluid pH and is soluble at a second aqueous fluid pH. The pH modifier is present in an amount to control the release of the active agent from the composition. The controlled-release composition is substantially free of a gelling or swellable excipient and does not contain a functional coating or a lipophilic component. The present invention also provides methods of making and using the controlled-release compositions.