The invention relates to a sustained release formulation for delivering one or more pharmaceutically active agents. The formulation comprises cross-linked high amylose starch and at least one pharmaceutically active agent, and optionally can be subdivided into smaller dosage forms where the smaller dosage forms have substantially the same sustained release properties as the formulation from which they were derived. The formulations can provide sustained release for up to at least 24 hours, and because of their divisability permits a recipient of the active agent or the person administering the active agent to titrate the dosage of the agent.