IMPLANTABLE MEDICAL DEVICE

• US 20110276148A1
• Filed: 10/16/2009
• Published: 11/10/2011
• Est. Priority Date: 10/16/2008
• Status: Active Grant

• Current Assignee: Depuy International Limited (Johnson & Johnson)
• Original Assignee: Depuy International Limited (Johnson & Johnson)
• Inventors: Wechsler, Sandra, Schachter, Deborah, Shissias, Raymond S., Li, Yufu
• Granted Patent: US 9,849,220 B2
• Time in Patent Office: Days
• US Class Current: 623/23.57
• CPC Class Codes: A61L 2300/406 Antibiotics
• CPC Class Codes: A61L 2300/608 having two or more layers
• CPC Class Codes: A61L 2420/08 Coatings comprising two or more layers
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence

Abstract

An implantable medical device, which comprises a device substrate, a coating on the substrate which includes a drug which is highly soluble in water, and a protective layer which overlies the coating. The protective layer comprises a polymer selected from the group consisting of polylactic acid, polyglycolic acid and a lactic acid/glycolic acid copolymer having a weight average molecular weight of not more than 40,000.

Claims

1. An implantable medical device, comprising:

a device substrate;

a coating on the substrate which includes a water soluble drug; and

a protective layer which overlies the coating, which comprises a polymer selected from the group consisting of polylactic acid, polyglycolic acid and a lactic acid/glycolic acid copolymer having a weight average molecular weight of not more than 40,000.

2. The device of claim 1, wherein the weight average molecular weight of the polymer is at least 10,000.

3. The device of claim 1, wherein the thickness of the protective layer is not more than about 30 μ

m.

4. The device of claim 1, wherein the thickness of the layer is at least about 2 μ

m.

5. The device of claim 1, wherein the polymer is a lactic acid/glycolic acid copolymer wherein the ratio by weight of lactic acid to glycolic acid is from 70:

30 to 30;

70.

6. The device of claim 1, wherein the drug is applied to the substrate in a dosage of at least about 250 μ

g.cm<sup>−

2</sup>.

7. The device of claim 1, wherein the drug is applied to the substrate in a dosage of not more than about 2000 μ

g.cm<sup>−

2</sup>.

8. The device of claim 1, wherein the solubility of the drug, measured by making a saturated solution of the drug in deionised water at 25 C, is at least 40 g.l⁻

1.

9. The device of claim 1, wherein the drug comprises an aminoglycoside antibiotic.

10. The device of claim 9, wherein the drug comprises gentamicin in the form of a salt with a strong acid.

11. The device of claim 1, which is a component of an orthopaedic joint prosthesis.

12. The device of claim 1, wherein the surface of the substrate on which the coating is provided at least in part by a metal.

13. The device of claim 1, which has been exposed to heat after application of the protective layer to the drug coating sufficient to cause the polymer of the protective layer to soften and to flow so as to reduce discontinuities in the protective layer resulting from the step of applying it to the drug coating.