Hydrogel-filled drug delivery reservoirs

• US 8,750,988 B2
• Filed: 11/09/2009
• Issued: 06/10/2014
• Est. Priority Date: 11/10/2008
• Status: Active Grant

• Current Assignee: MED-EL Elektromedizinische Gerate GmbH (MED-EL Corporation)
• Original Assignee: MED-EL Elektromedizinische Gerate GmbH (MED-EL Corporation)
• Inventors: Jolly, Claude, Hessler, Roland, Dhanasingh, Anandhan, Groll, Jrgen
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): Morales, Jon Eric C
• Application Number:
  US12/614,959
• Publication Number:
  US 20100121422A1
• Time in Patent Office: 1,674 Days
• Field of Search: 607/3, 604/891.1
• US Class Current: 607/3
• CPC Class Codes: A61K 47/36 Polysaccharides; Derivatives thereof, e.g. gums, starch, alginate, dextrin, hyaluronic acid, chitosan, inulin, agar or pectin
• CPC Class Codes: A61K 9/0019 Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner non-active ingredients are additionally classified in A61K47/00
• CPC Class Codes: A61K 9/0024 Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L
• CPC Class Codes: A61K 9/0046 Ear
• CPC Class Codes: A61K 9/06 Ointments; Bases therefor; Other semi-solid forms, e.g. creams, sticks, gels composition of ointments, creams or gels A61K47/00
• CPC Class Codes: A61M 2039/0205 for injecting media
• CPC Class Codes: A61M 2039/0276 for introducing or removing fluids into or out of the body
• CPC Class Codes: A61M 2039/0282 with implanted tubes connected to the port
• CPC Class Codes: A61M 2205/054 with electrotherapy
• CPC Class Codes: A61M 2210/0662 Ears
• CPC Class Codes: A61M 31/002 Devices for releasing a drug at a continuous and controlled rate for a prolonged period of time artificial gland structures or devices A61F2/022; intra-uterine contraceptive devices A61F6/14; tampons for introducing into the vagina A61F13/20, A61L15/00; suppositories or bougies for intra-vaginal or intra-uterine application A61K9/02; physical forms of medicinal preparations for sustained or differential drug release A61K9/20, A61K9/50
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: A61N 1/0568 with drug delivery

Abstract

A cochlear implant electrode includes an implantable electrode carrier having an outer surface with electrode contacts for electrically stimulating nerve tissue of the inner ear of a patient. A drug lumen is within the electrode carrier and adapted to receive a therapeutic fluid. The drug lumen contains delivery openings to the outer surface of the electrode carrier and a hydrogel matrix disposed between the drug lumen and the one or more delivery openings and adapted to swell in volume when exposed to the therapeutic fluid. The hydrogel matrix is adapted to control diffusion of the therapeutic fluid from the drug lumen through the delivery openings to the outer surface of the electrode carrier.

Claims

1. 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.

2. An electrode according to claim 1, wherein the drug lumen is adapted to contain a treatment period amount of therapeutic fluid for an extended treatment period.

3. An electrode according to claim 1, wherein the hydrogel matrix has an adjustable pore size which controls diffusion rate of the therapeutic fluid.

4. An electrode according to claim 1, wherein the hydrogel matrix is based on hyaluronic acid.

5. An electrode according to claim 1, wherein the hydrogel matrix is based on a three-dimensional network of cross-linked hydrophilic polymer chains.

6. An electrode according to claim 1, wherein the hydrogel matrix has a mesh size small enough to resist entry of bacteria.

7. An electrode according to claim 1, wherein the therapeutic fluid includes dexamethasone.

8. An electrode array according to claim 1, wherein the electrode is adapted to release between 5 μ

g and 600 μ

g of dexamethasone during an initial 24 hour period of use.

9. An electrode according to claim 1, further comprising:

a refilling arrangement for refilling the drug lumen in an implanted electrode with additional therapeutic fluid.