Electrochemical methods for the quantifiably controlled delivery of biologically active compounds to well-defined locations will be developed. In one method the active substance will be bound in a polymer to the surface of a solid electrode. It will be released electrochemically. In a second method, an electronically switchable membrane will be used to control the flow of ionic substances. Compounds to be delivered include neurotransmitters and a variety of ionic drugs. Electroactive polymers which covalently bind drugs and conducting polymers which ionically bind drugs will be developed. These electrodes and membranes will be tested as an alternative to iontophoresis and timed-release drug delivery devices with release rate control and on/off capability will be explored.