Patent ID: 8404704
Filing Date: 2013-03-26
Classification: A61P,C07D

Abstract:
1. A method of preparing a pharmaceutical composition having controlled systemic absorption of rifaximin, said method comprising combining two or more polymorphs of rifaximin selected from the group consisting of Form α, Form β, and Form γ wherein the amount of absorption of said rifaximin is modulated by adjusting the relative proportions of Form α, Form β, and Form γ rifaximin to form a mixture of rifaximin polymorphs and combining the mixture with a pharmaceutically acceptable excipient or carrier, 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, wherein the rifaximin Form β has x-ray powder diffraction pattern peaks at about 5.4°; 9.0°; and 20.9° 2-θ, and wherein the rifaximin Form γ has x-ray powder diffraction pattern peaks at about 5.0°, 7.1°, and 8.4° 2-θ,