title: Solid state characterization of olanzapine polymorphs using vibrational spectroscopy.
abstract: FT-Raman, infrared and near infrared investigations of two polymorphs of olanzapine are presented, establishing the main features that allow the discrimination of these crystalline forms using vibrational spectroscopic methods. Ab initio calculations on the basis of the density functional theory were used to determine the stable conformations. The calculated vibrational spectra were compared to the experimental ones in order to identify the conformers corresponding to each polymorph and to assign the vibrational bands to the internal vibrations of the olanzapine molecule. Our results support the hydrogen bonding pattern proposed by the reported crystalline structure and provide valuable information on the structural and thermodynamical relationship between the investigated polymorphs.
authors.affiliation: Department of Physical Chemistry, University of Duisburg-Essen, Essen D45117, Germany. alejandro.ayala@uni-due.de
authors.forename: A P
authors.initials: AP
authors.lastname: Ayala
authors.forename: H W
authors.initials: HW
authors.lastname: Siesler
authors.forename: R
authors.initials: R
authors.lastname: Boese
authors.forename: G G
authors.initials: GG
authors.lastname: Hoffmann
authors.forename: G I
authors.initials: GI
authors.lastname: Polla
authors.forename: D R
authors.initials: DR
authors.lastname: Vega
mesh_terms: D014150:Antipsychotic Agents / Q000737:chemistry; D001569:Benzodiazepines / Q000737:chemistry; D003460:Crystallization; D004581:Electronics; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008958:Models, Molecular; D008962:Models, Theoretical; D008968:Molecular Conformation; D015394:Molecular Structure; D000077152:Olanzapine; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D013057:Spectrum Analysis / Q000379:methods*; D013059:Spectrum Analysis, Raman; D014732:Vibration
chemical_list: D014150:Antipsychotic Agents; D001569:Benzodiazepines; D000077152:Olanzapine