| abstract |
The object of the present invention are crystalline polymorphic forms of rifaximin (INN) designated rifaximin α and rifaximin β and a weakly crystalline form called rifaximin γ, which are useful for the production of rifaximin containing medicinal products for oral and surface use and obtained by the crystallization process performed by warm dissolution of crude of rifaximin in ethyl alcohol and causing the product to crystallize by adding water at a certain temperature and for a period of time, followed by drying under controlled conditions, until the precise water content of the final product is reached. |