XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
315
T6: P–23
Vibrational analysis of inulin
Cristina Bălan
1
, Mihaela Chiș
1
, and Monica Baia
1
1
Faculty of Physics, Babeș-Bolyai University, M. Kogălniceanu 1, 400084 Cluj-Napoca, Romania
e-mail: mihaelaioanachis@gmail.com
Inulin is an organic, linear molecule with an extensive field of applicability, found in plants,
fruits or in common vegetables [1]. The chemistry of inulin molecule is quite simple because it
is a natural polysaccharide, formed by up to 60 units of fructose and just one end unit of glucose
[1]. One of the most distinctive structural characteristics is the chemical bonding between the
two consecutive fructoses, which means that the inulin passes though the upper, human
digestive system and stops in the large bowel where it increases the production of microflora [2].
Because of this behavior, inulin is a natural prebiotic that has a great impact on the human
health, and its applicability, from domains like medicine/pharmacology to food industry,
recommending it as a favorable molecule for drug delivery [1–3].
In spite of its large applicability area there are no studies reporting about a complete
vibrational analysis of the inulin molecule. Therefore, the aim of this study was to obtain a
comprehensive vibrational investigation of inulin both from an experimental and theoretical
point of view. Accordingly, Raman and IR absorption spectra were recorded and are presented
in Figure 1, and the assignment of the vibrational modes was performed by using the theoretical
data of the density functional theory (DFT) based simulations carried out at B3LYP/6-311+G*
and BPW91/6-311+G* theoretical levels.
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Fig. 1 A. Experimental (a) and simulated IR spectra of inulin obtained with B3LYP/6-311+G* (b) and BPW91/6-
311+G* (c) theoretical levels; Experimental (a) and simulated Raman spectra of inulin obtained with B3LYP/6-
311+G* (b) and BPW91/6-311+G* (c) theoretical levels.
Keywords: inulin; IR spectroscopy; Raman spectroscopy; DFT
References
[1] A.M. Mensink, H.W. Frijlink, K.V. Maarschalk, Carbohydrate Polymers (2015) 405.
[2] G. Kelly, Alternative Medicine Review: A Journal of Clinical Therapeutic (2008) 315.
[3] A.K. Jain, V.Sood, M. Bora, R. Vasita, D.S. Katti, Carbohydrate Polymers (2014) 225.
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XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
316
T6: P–24
Analysis of structural polymorphism of sorafenib tosylate
by FT-IR and Raman spectroscopy
Gabriela Wiergowska
1,2
, Kornelia Lewandowska
3
, Mikołaj Mizera
1
,
and Judyta Cielecka-Piontek
1
1
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Poznan University of Medical
Sciences, Grunwaldzka 6, 60-780 Poznań, Poland, e-mail: mikolajmizera@gmail.com
2
Pozlab sp.z.o.o. Poznań, Parkowa 2, 60-775 Poznań
3
Department of Molecular Crystals, Institute of Molecular Physics of the Polish Academ
of Sciences, Poznan, Poland
Sorafenib
(4-[4-[[4-chloro-3-(trifluoromethyl)phenyl]carbamoylamino]phenoxy]-N-
methylpyridine-2-carboxamide;4-methylbenzenesulfonic acid) is a kinase inhibitor drug
approved for the treatment of primary kidney cancer (advanced renal cell carcinoma), advanced
primary liver cancer (hepatocellular carcinoma), and radioactive iodine resistant advanced
thyroid carcinoma. It inhibits the VEGFR-2/PDGFR-beta signaling cascade therefore block
tumor angiogenesis. At present sorafenib tosylate is known to exist in two structural
polymorphic forms: I and III.
This work had two main aims. The first was identification of sorafenib tosylate by
application of FT-IR and Raman spectroscopy supported by quantum chemical calculations
using a Becke, 3-parameter, Lee-Yang-Parr (B3LYP) hybrid functional with a 6-31G(d,p)
standard basis set. The second, to confirm the identity of I and III polymorphic forms of
sorafenib tosylate by using Raman and FT-IR spectra.
Based on theoretical calculations using the 6-31G(d,p) basis set, the bands typical of
sorafenib tosylate were identified in FT-IR and Raman experimental spectra. The vibrational
infrared spectrum was recorded between 400 and 7000 cm-1 while the Raman scattering
spectrum was obtained with a spectrometer at a laser excitation wavelength of 1064 nm. For the
identification of sorafenib tosylate the following functional groups of the compound were
considered during FT-IR and Raman analysis: 4-chloro-3-trifluoromethylphenyl, ureido,
phenoxy groups and piridine-2-carboxylic-acid, and methyamide-4-methylbensene sulfonate.
For those groups, the positions, shapes and intensities of bands were determined on the basis of
theoretical results obtained from quantum chemical calculations. A good agreement between the
empirical and theoretical reference standards was observed.
The identification of I and III polymorphic forms of sorafenib tosylate was confirmed via
FT-IR and Raman spectroscopy coupled with DFT calculations. While PXRD data were used as
reference standard during identification of I and III polymorphic forms of sorafenib tosylate.
The possibility of applying the molecular electrostatic potential (MEP) to predict and interpret
the chemical reactivity of sorafenib tosylate was also assessed. According to theoretical
calculations (B3LYP/6-31G(d,p)), the MEP shows that the negative potential site is over the
aliphatic domains whereas the positive potential sites are around the aromatic moieties. The
frontier molecular orbitals, highest occupied molecular orbital (HOMO) and lowest unoccupied
molecular orbital (LUMO) were established.
The application of FT-IR and Raman techniques can be recommended for identification of
sorafenib tosylate. Moreover, the study resulted in developing an spectroscopic approach for
identification of polymorphic forms of sorafenib tosylate.
Keywords: sorafenib tosylate; structural polymorphism, FT-IR, Raman; DFT
Acknowledgment
This study was supported by SONATA grant from the National Science Centre Poland-DEC
2013/09/D/NZ7/02525.
This research was supported in part by PL-Grid Infrastructure.
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