title: [Preparation and characterization of Forms A and B of benazepril hydrochloride].
abstract: To prepare Form A and Form B of benazepril hydrochloride and to compare the differences in spectrums, thermodynamics and crystal structure between two polymorphic forms.
  
  
  
  Form A and Form B of benazepril hydrochloride were characterized by Fourier transform infrared spectroscopy (IR), thermal gravimetric analysis (TG), differential scanning calorimetry (DSC), powder x-ray diffraction (PXRD) and single crystal x-ray diffraction (SCXRD).
  
  
  
  Preparation method, crystal structure and polymorphic stability of Form A and Form B of benazepril hydrochloride were obtained. Based on the analysis of crystal structure of both polymorphs, Form A belonged to monoclone space group P2(1) with a=7.8655(4)Å, b= 11.7700(6)Å, c= 13.5560(7)Å, β= 102.9470(10)°, V=1223.07 (11)Å(3) and Z=2, while Form B belonged to orthorhombic space group P212121, with a=7.9353(8)Å, b=11.6654(11)Å, c=26.6453(16)Å, V=2466.5(4)Å(3) and Z=4. From the DSC and XRD results, Form B of benazepril hydrochloride could be transformed into Form A after heating treatment.
  
  
  
  Form A and Form B of benazepril hydrochloride are both anhydrous and displayed different polymorphs due to different molecular configuration. Furthermore, Form A exhibits more stable than Form B at high temperatures.
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Fang
authors.forename: Xiu-rong
authors.initials: XR
authors.lastname: Hu
authors.forename: Jian-ming
authors.initials: JM
authors.lastname: Gu
authors.forename: Guan-xi
authors.initials: GX
authors.lastname: Chen
authors.forename: Jian-yue
authors.initials: JY
authors.lastname: Feng
authors.forename: Gu-ping
authors.initials: GP
authors.lastname: Tang
mesh_terms: D001552:Benzazepines / Q000737:chemistry*; D003460:Crystallization; D004355:Drug Stability; D008968:Molecular Conformation
chemical_list: D001552:Benzazepines; C044946:benazepril