Implantable pumps.

Implantable drug-delivery pumps are being developed to provide the external control of delivery rate or to deliver volumes of drug that are beyond the capabilities of conventional controlled-release formulations. The delivery of insulin to diabetics and chemotherapeutic agents to cancer patients represents the two major applications of such devices, but other applications (chronic pain control, Alzheimer's disease, spasticity, etc.) exist or have been proposed. The most popular device is the Infusaid which is driven by a fluorocarbon vapor-liquid mixture to provide a constant delivery rate. Implantable peristaltic pumps have recently been developed to deliver drugs at variable rates according to a physician-preprogrammed schedule which is actuated with the aid of transcutaneous telemetry. Other devices are available in the literature, if not yet in clinical application.