Solid-state NMR and IR for the analysis of pharmaceutical solids: polymorphs of fosinopril sodium.
The two polymorphic modifications of fosinopril sodium have been characterized as to their differences in melting behaviour, powder X-ray diffraction patterns, Fourier transform infrared spectra (FTIR), and solid-state 31P- and 13C-NMR spectra. The polymorphs were found to be enantiotropically related based upon melting point, heat of fusion, and solution mediated transformation data. Analysis of the solid-state FTIR and 13C-NMR data indicated that the environment of the acetal side chain of fosinopril sodium differed in two polymorphs, and that there might be cis-trans isomerization about the C6-N peptide bond. These conformational differences are postulated as the origin of the observed polymorphism.
Brittain
H G
HG
Bristol-Myers Squibb Pharmaceutical Research Institute, New Brunswick, NJ 08903.
Morris
K R
KR
Bugay
D E
DE
Thakur
A B
AB
Serajuddin
A T
AT
D003460:Crystallization; D017328:Fosinopril / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism; D014961:X-Ray Diffraction
D017328:Fosinopril