1: Radiat Res. 2004 Dec;162(6):616-22. 

Attempts at Correlation of the Radiolytic Species of Irradiated Solid-State
Captopril Studied by Multi-frequency EPR and HPLC.

Engalytcheff A, Debuyst R, Vanhaelewyn GC, Callens FJ, Tilquin B.

Laboratory of Chemical and Physicochemical Analysis of Drugs (CHAM), UCL, B.1200
Brussels, Belgium.

Engalytcheff, A., Debuyst, R., Vanhaelewyn, G. C. A. M., Callens, F. J. and
Tilquin, B. Attempts at Correlation of the Radiolytic Species of Irradiated
Solid-State Captopril Studied by Multi-frequency EPR and HPLC. Radiat. Res. 162,
616- 622 (2004).The purpose of this study was to provide insight into the
processes that occur after the irradiation of solid-state drugs. Electron
paramagnetic resonance (EPR) experiments were performed at two different
frequencies, X-band (about 9.5 GHz) and Q-band (about 34 GHz), to identify the
radicals present in irradiated captopril. The results confirmed that an
irradiated drug can trap several main radicals. Moreover, the radical
composition varied as a function of the treatment. In addition, non-volatile
final products were studied by liquid chromatography coupled to UV and to mass
spectrometry (LC-MS). The variation of the radical composition did not influence
the profile of the final products; this appears to indicate that, in the case of
captopril, the trapped radicals observed by EPR are not the main precursors of
the final products. Finally, high-performance liquid chromatography data appear
to indicate that radiosterilization of captopril is feasible.

PMID: 15548111 [PubMed - in process]