Patent ID: 6162462
Filing Date: 2000-12-19
Classification: A61K,A61P

Abstract:
A method of producing prolonged analgesia, comprising administering to a subject in need of such treatment a liposomal bupivacaine composition,wherein said composition is prepared by (i) incubating a bupivacaine solution, at a pH which prevents precipitation of the bupivacaine from the solution, with a suspension of liposomes having a greater concentration of ammonium ions inside said liposomes than outside said liposomes, and (ii) removing non-encapsulated bupivacaine,wherein said liposomes are giant multivesicular (GMV) liposomes, at least 2 microns in diameter, prepared by (a) vortexing a lipid film with an aqueous solution of ammonium sulfate, (b) homogenizing the resulting suspension to form a suspension of small unilamellar vesicles (SUV), and (c) repeatedly freeze-thawing said suspension of SUV in liquid nitrogen followed by water.