Patent ID: 8173801
Filing Date: 2012-05-08
Classification: A61P,C07D

Abstract:
1. A process for the production of rifaximin in polymorphic Form α, comprising: dissolving rifaximin in an alcoholic solvent at a temperature between approximately 45° C. and approximately 65° C.; precipitating the rifaximin by adding water to the alcoholic solvent to form a suspension and by lowering the temperature of the suspension to between approximately 0° C. and approximately 50° C.; and drying the rifaximin for a period of time between approximately 2 and approximately 72 hours to form rifaximin in polymorphic Form α, wherein the rifaximin Form α has a water content of between 3.0%-4.5%, and wherein the rifaximin Form α has x-ray powder diffraction pattern peaks at about 7.4° ; 19.7° ; 21.0° and 22.1° 2-θ.