Details for Patent: 8,158,781
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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; Giuseppe Claudio (Bologna, IT), Campana; Manuela (Bologna, IT), Braga; Dario (Bologna, IT), Confortini; Donatella (Bologna, IT), Cannata; Vincenzo (Bologna, IT), Righi; Paolo (Bologna, IT), Rosini; Goffredo (Bologna, IT) |
Assignee: | Alfa Wassermann, S.p.A. (Bologna, IT) |
Filing Date: | Mar 04, 2011 |
Application Number: | 13/041,332 |
Claims: | 1. Rifaximin in polymorphic Form .alpha., wherein the rifaximin Form .alpha.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 between 3.0%-4.5%. 2. The rifaximin of claim 1, wherein the rifaximin Form .alpha. has a water content of 3.0%. 3. The rifaximin of claim 1, wherein the rifaximin Form .alpha. has a water content of 4.5%. 4. Rifaximin in polymorphic Form .beta., wherein the rifaximin Form .beta.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 between 4.5%-5.0%. 5. The rifaximin of claim 2, wherein the rifaximin Form .beta. has a water content of 5.0%. 6. Rifaximin in polymorphic Form .gamma., wherein the rifaximin Form .gamma.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 1%. 7. The rifaximin of claim 5, wherein the rifaximin Form .gamma. has a water content of 0%. 8. The rifaximin of claim 5, wherein the rifaximin Form .gamma. has a water content of 1%. |