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Journal of Spectroscopy
Volume 2017, Article ID 6505706, 11 pages
Research Article

Spectroscopic Characterization of Omeprazole and Its Salts

1Krka d.d., Novo Mesto, Šmarješka c. 6, SI-8501 Novo Mesto, Slovenia
2National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia

Correspondence should be addressed to Jože Grdadolnik; is.ik@kinlodadrg.ezoj

Received 9 June 2017; Accepted 24 September 2017; Published 1 November 2017

Academic Editor: Yiannis Sarigiannis

Copyright © 2017 Tomislav Vrbanec et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


During drug development, it is important to have a suitable crystalline form of the active pharmaceutical ingredient (API). Mostly, the basic options originate in the form of free base, acid, or salt. Substances that are stable only within a certain pH range are a challenge for the formulation. For the prazoles, which are known to be sensitive to degradation in an acid environment, the formulation is stabilized with alkaline additives or with the application of API formulated as basic salts. Therefore, preparation and characterization of basic salts are needed to monitor any possible salinization of free molecules. We synthesized salts of omeprazole from the group of alkali metals (Li, Na, and K) and alkaline earth metals (Mg, Ca). The purpose of the presented work is to demonstrate the applicability of vibrational spectroscopy to discriminate between the OMP and OMP-salt molecules. For this reason, the physicochemical properties of 5 salts were probed using infrared and Raman spectroscopy, NMR, TG, DSC, and theoretical calculation of vibrational frequencies. We found out that vibrational spectroscopy serves as an applicable spectroscopic tool which enables an accurate, quick, and nondestructive way to determine the characteristic of OMP and its salts.