Details for Patent: 7,612,199

Title:	Polymorphic forms .alpha., .beta., and .gamma. of rifaximin
Abstract:	Crystalline polymorphous forms of rifaximin (INN) antibiotic named rifaximin .alpha. and rifaximin .beta., and a poorly crystalline form named rifaximin .gamma., useful in the production of medicinal preparations containing rifaximin for oral and topical use and obtained by means of a crystallization carried out by hot-dissolving the raw rifaximin in ethyl alcohol and by causing the crystallization of the product by addition of water at a determinate temperature and for a determinate period of time, followed by a drying carried out under controlled conditions until reaching a settled water content in the end product, are the object of the invention.
Inventor(s):	Viscomi; Guiseppe Glaudio (Bologna, IT), Campana; Manuela (Bologna, IT), Braga; Dario (Bologna, IT), Confortini; Donatella (Bologna, IT), Cannata; Vicenzo (Bologna, IT), Righi; Paolo (Bologna, IT), Rosini; Goffredo (Bologna, IT)
Assignee:	Alfa Wassermann, S.p.A. (Bologna, IT)
Filing Date:	Jun 04, 2009
Application Number:	12/478,638
Claims:	1. Rifaximin in polymorphic form .alpha., wherein the rifaximin has x-ray powder diffraction pattern peaks at about 7.4.degree.; 19.7.degree.; 21.0.degree. and 22.1.degree. 2-.theta. and wherein the rifaximin has a water content of less than 4.5%. 2. The compound of claim 1, wherein the rifaximin has a water content of between 2.0-3.0%. 3. The compound of claim 1, wherein the rifaximin has a water content of 2.5%. 4. Rifaximin in polymorphic form .beta., wherein the rifaximin has x-ray powder diffraction pattern peaks at about 5.4.degree.; 9.0.degree.; and 20.9.degree.2.theta. and wherein the rifaximin has a water content of greater than 5%. 5. The compound of claim 4, wherein the rifaximin has a water content of between 5.0-6.0%. 6. Rifaximin in polymorphic form .gamma., wherein the rifaximin has x-ray powder diffraction pattern peaks at about 5.0.degree., 7.1.degree., and 8.4.degree.2-.theta. and wherein the rifaximin has a water content of from between 0% to 2%. 7. The compound of claim 6, wherein the rifaximin has a water content of 1.5%.