The structure-property relationship of four crystal forms of rifaximin

The crystal structures of four crystal forms of rifaximin, named alpha, beta, delta and epsilon, have been elucidated by a combination of single crystal and powder diffraction experiments with synchrotron and X-ray sources. The crystal structures of the delta and epsilon forms have been determined from powder diffraction data alone. Hot stage microscopy has also been of paramount importance in the understanding of the beta -> alpha conversion process.