Free radicals in irradiated drugs: an EPR study.
Exposure of dry powder forms of the drugs nitrendipine, nifedipine, felodipine, and nimodipine to gamma-radiation results in the formation of free radicals detected by electron paramagnetic resonance (EPR) spectroscopy. The four structurally related drugs show qualitatively identical EPR spectral features in terms of g-values, the qualitative descriptive parameter. These radicals are very stable, surviving long periods of time in excess of 9 months and possibly beyond conventional shelf-life of the drugs. The residual radical population is high enough to be detectable after long storage. Administration of such radiation-treated drugs may present patients with quantities of free radicals and possibilities of secondary cell damage.
Taiwo
F A
FA
School of Pharmacy and Pharmaceutical Sciences, De Montfort University, The Gateway, Leicester, UK. ttaiwo@dmu.ac.uk
Patterson
L H
LH
Jaroszkiewicz
E
E
Marciniec
B
B
Ogrodowczyk
M
M
D002121:Calcium Channel Blockers / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D015736:Felodipine / Q000528:radiation effects; D005609:Free Radicals / Q000528:radiation effects; D005720:Gamma Rays; D009543:Nifedipine / Q000528:radiation effects; D009553:Nimodipine / Q000528:radiation effects; D009568:Nitrendipine / Q000528:radiation effects
D002121:Calcium Channel Blockers; D005609:Free Radicals; D009553:Nimodipine; D009568:Nitrendipine; D009543:Nifedipine; D015736:Felodipine