Pharmaceutical compositions comprising polymorphic forms alpha, beta, and gamma of rifaximin

Abstract

Crystalline polymorphous forms of rifaximin (INN), referred to as rifaximin α and rifaximin β, and a poorly crystalline form referred to as rifaximin γ, useful in the production of medicaments containing rifaximin for oral and topical use and 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 addition of water at a fixed temperature and for a fixed period of time, followed by a drying under controlled conditions until reaching a precise water content in the end product, are the object of the invention.

1 . A pharmaceutical composition comprising rifaximin in polymorphic form α. 
     
     
         2 . A pharmaceutical composition comprising rifaximin in polymorphic form β. 
     
     
         3 . A pharmaceutical composition comprising rifaximin in polymorphic form γ.