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International Journal of Photoenergy
Volume 2014, Article ID 953619, 7 pages
Research Article

Effect of UV Irradiation and Temperature on Free Radical Properties in Dehydrocholic and Ursodeoxycholic Acids: An EPR Study

1Department of Analytical Chemistry, Faculty of Pharmacy, Medical University of Silesia in Katowice, 4 Jagiellońska Street, 41-200 Sosnowiec, Poland
2Department of Biophysics, Faculty of Pharmacy, Medical University of Silesia in Katowice, 8 Jedności Street, 41-200 Sosnowiec, Poland

Received 26 May 2014; Revised 22 August 2014; Accepted 7 September 2014; Published 25 November 2014

Academic Editor: Franca Morazzoni

Copyright © 2014 Małgorzata Dołowy 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.


The effect of UV irradiation and temperature on the formation and properties of free radicals in two pharmaceutical important bile acids, such as dehydrocholic (DH) and ursodeoxycholic acids (UDC), was examined. Electron paramagnetic resonance (EPR) spectroscopy was applied to determine the paramagnetic character of UV irradiated and thermally sterilized drugs. Thermal and UV irradiation sterilizations of both compounds were carried out at different conditions according to pharmaceutical norms. The performed EPR measurements of UV irradiated and thermally sterilized DH and UDC samples proved the existence of the complex free radical systems in examined bile acids. Significant influence of UV irradiation in comparison with applied thermal sterilization on free radical concentrations in DH and UDC samples was observed. The results pointed out that thermal method is most suitable for bile acid sterilization. Therefore, this kind of sterilization should be applied in practice.