Polymorphous forms of rifaximin, processes for their production and use thereof in medicinal preparations

US7045620B2 · kind B2 · utility

Assignee

• ALFA WASSERMANN S.P.A. · IT

Inventors

• Giuseppe Claudio Viscomi · Monterotondo, IT
• Manuela Campana · Bologna, IT
• Dario Braga · Bologna, IT
• Donatella Confortini · Bologna, IT
• Vincenzo Cannata · Sasso Marconi, IT
• Denis SEVERINI · Bologna, IT
• Paolo Righi · Bologna, IT
• Goffredo Rosini · Bologna, IT

Key dates

• Filing date: Dec 5, 2003
• Grant date: May 16, 2006
• Expiry date: Jun 19, 2024

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61P31/06
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

Crystalline polymorphous forms of the rifaximin (INN) antibiotic named rifaximin α and rifaximin β, and a poorly crystalline form named rifaximin γ have been discovered. These forms are useful in the production of medicinal preparations for oral and topical use and can be obtained by means of a crystallization process carried out by hot-dissolving the raw rifaximin in ethyl alcohol and by causing the crystallization of the product by the addition of water at a determinate temperature and for a determinate period of time. The crystallization is followed by drying carried out under controlled conditions until a specific water content is reached in the end product.