Polymorphism in drugs investigated by low wavenumber Raman scattering
VIBRATIONAL SPECTROSCOPY, 45 (2, SI):
112-116 (2007)Workshop on Foundations and Applications of Raman Spectroscopy, Ceara,
BRAZIL, SEP 24-26, 2006.DOI: 10.1016/j.vibspec.2007.06.004
Abstract
Raman scattering is a powerful method to investigate the polymorphism in
drugs due to its remarkable sensitivity to the crystalline structure of
molecular compounds. The sensitivity of the technique is strongly
enhanced when considering the low wavenumber Raman active vibrational
modes, since molecular skeleton deformations, librations and
translations usually lay below 200 cm(-1) and are directly related to
the polymorphism phenomenon. In this work, the potential of the low
energy Raman spectrum in the investigation of polymorphism of drugs is
discussed. Several examples are presented showing the use of this
spectral range in the understanding of the mechanism involved in the
polymorphic behavior of active pharmaceutical ingredients. The results
show that low wavenumber Raman spectra can be used for rapidly and
accurately identifying the polymorphic forms of an active ingredient.
Additional valuable information is obtained when combining spectroscopic
measurements with ab initio calculations, X-ray diffraction measurements
and thermal analysis. (c) 2007 Elsevier B.V. All rights reserved.