Drug delivery by program or sensor controlled infusion devices.

The prolonged controlled administration of drugs could benefit the treatment of several diseases. In some instances variable delivery rates are required, e.g. in the treatment of diabetes. Program controlled externally portable devices and fixed rate implantable pumps are rapidly gaining clinical acceptance. Widespread use of the considerably more complex implantable devices with variable rates for use in diabetes therapy is hampered by the persistant problem of the incompatibility of insulin with the pump at body conditions. The ideal devices, feed-back controlled implants, cannot be realized since long-term implantable sensors, e.g. of glucose, are not yet available. Prospective clinical trials are running for all applications to clarify the cost-benefit-risk relationships.