EPR INVESTIGATION OF ILLUMINATED AND UV IRRADIATED NIFEDIPINE
Pages 68-71
Gabriella Schmutzer, G. Damian, O. Cozar, V. Miclaus, Silvia Imre, Dina Petrisor
Abstract
The aim of the present work is to study by Electron Paramagnetic Resonance (EPR) spectroscopy the behavior of the illumination- and UV irradiation-induced free radicals in the nifedipine [C17H18N2O6, 3,5-pyridine dicarboxylic acid, 1,4-dihydro-2,6-dimethyl-4-(2-nitro-phenyl)- dimethyl ester], to characterize the specific features of these radicals. Powder samples of nifedipine were investigated for a comparison between radiation damage in commercial tablet and in active substance. The nifedipine has not EPR signal before illumination or before UV irradiation, but the relative yielding of free radicals, appeared after irradiation, depends on the exposure time. Some spectroscopic properties and suggestions concerning possible structure of the free radicals are discussed in this paper.