Implantable polymeric device for sustained release of buprenorphine
The present invention provides compositions, methods, and kits for treatment of opiate addiction and pain. The invention provides a biocompatible nonerodible polymeric device which releases buprenorphine continuously with generally linear release kinetics for extended periods of time. Buprenorphine is released through pores that open to the surface of the polymeric matrix in which it is encapsulated. The device may be administered subcutaneously to an individual in need of continuous treatment with buprenorphine.
1. A method for treating opiate addiction in a human in need thereof, comprising subcutaneously implanting at least one implantable device comprising buprenorphine and ethylene vinyl acetate copolymer (EVA), wherein said device comprises a polymeric matrix comprising buprenorphine blended with said EVA copolymer, wherein said buprenorphine is continuously released in vivo over a sustained period of time through pores that open to the surface of said matrix at a rate that results in a steady state plasma buprenorphine level for at least about 3 months, wherein said device does not comprise a coating that is impermeable to buprenorphine, wherein said device does not comprise external medical equipment, and wherein said at least one device releases buprenorphine at a rate that results in a therapeutically effective steady state plasma level of about 0.1 ng/ml to about 1 ng/ml to a human in need of treatment for opiate addiction.
2. A method according to claim 1 , wherein said EVA comprises about 33% vinyl acetate.
3. A method according to claim 2 , wherein said implantable device comprises about 10% to about 85% buprenorphine.
4. A method according to claim 3 , wherein said implantable device comprises about 50% buprenorphine.
5. A method according to claim 3 , wherein said implantable device comprises about 75% buprenorphine.
6. A method according to claim 2 , wherein the implantable device is produced by an extrusion process.
7. A method according to claim 6 , wherein the implantable device comprises dimensions of about 1.5 to about 5 mm in diameter and about 0.5 to about 7 cm in length.
8. The method of claim 1 , wherein said device is washed with ethanol prior to subcutaneous implantation.
9. The method of claim 8 , wherein said washing with ethanol removes surface buprenorphine and reduces the initial burst of buprenorphine released in vivo after subcutaneous implantation relative to an unwashed device.