Patent ID: 8750988

Claim:
A cochlear implant electrode comprising: an implantable electrode carrier having an outer surface including a plurality of electrode contacts for electrically stimulating nerve tissue of the inner ear of a patient; and a drug lumen within the electrode carrier, the drug lumen having an inner surface and adapted to receive a therapeutic fluid and containing: i. one or more delivery openings disposed toward a distal end of the drug lumen and configured to permit the therapeutic fluid to flow to the outer surface of the electrode carrier, and ii. a coating of a dry hydrogel material disposed on at least a portion of the inner surface of the drug lumen, the coating covering the one or more delivery openings and adapted to swell in volume into a swollen hydrogel matrix that fills the drug lumen at its distal end when exposed to the therapeutic fluid wherein the hydrogel material is characterized by a pore size adapted to: i. release air from the drug lumen through the one or more delivery openings when the therapeutic fluid is added to the dry hydrogel material, and ii. control diffusion of the therapeutic fluid through the swollen hydrogel matrix within the drug lumen and through the one or more delivery openings to the outer surface of the electrode carrier.