title: Polymorphism-structure relationships of rifamexil, an antibiotic rifamycin derivative.
abstract: The polymorphism of rifamexil, a rifamycin derivative, has been investigated by thermomicroscopy, differential thermal analysis (differential scanning calorimetry-thermogravimetry), IR spectroscopy, and X-ray powder diffraction. Two crystalline forms, an amorphous material, and three solvates have been studied. The crystal structures of two solvates have also been determined by single-crystal X-ray techniques. Although the overall conformation of rifamexil is very similar in the two compounds, marked differences occur between the two crystal packings, due to differences both in the mutual orientation of the molecules and in the rifamexil-solvent interactions. Multivariate statistical methods have been used to identify the principal structural parameters determining the biological activity of the rifamycins.
authors.affiliation: Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Parma, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Bacchi
authors.forename: G
authors.initials: G
authors.lastname: Mori
authors.forename: G
authors.initials: G
authors.lastname: Pelizzi
authors.forename: G
authors.initials: G
authors.lastname: Pelosi
authors.forename: M
authors.initials: M
authors.lastname: Nebuloni
authors.forename: G B
authors.initials: GB
authors.lastname: Panzone
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D015394:Molecular Structure; D012294:Rifamycins / Q000737:chemistry*; D012997:Solvents; D013055:Spectrophotometry, Infrared; D013329:Structure-Activity Relationship; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D012294:Rifamycins; D012997:Solvents; C063797:rifamexil