The use of multi-frequency EPR techniques to identify the radicals produced in irradiated β-blockers

Alix Engalytcheff, Matthias Kolberg, Anne Laure Barra, K. Kristoffer Andersson, Bernard Tilquin

Research output: Contribution to journalReview article

12 Citations (Scopus)

Abstract

The identification of radicals trapped in irradiated drugs can be very intricate. A multi-frequency electron paramagnetic resonance (EPR) study is proposed to resolve this problem. The Q-band (ca. 34 GHz) comparison with X-band (ca. 9 GHz) did not show significant differences for the four β-blockers studied (atenolol, esmolol, nadolol and propranolol). The use of a higher frequency (285 GHz) was required. It enabled us to determine the g-tensor values of the radicals present in atenolol and esmolol, respectively, g1 = 2.0086, g2 = 2.0059 and g3 = 2.0021 and g1 = 2.0066, g2 = 2.0044 and g3 = 2.0021. The latter was assigned as a phenoxyl radical, which can not be the case for the former. Therefore, radicals produced in esmolol may result from a more complex mechanism than the abstraction followed by the diffusion of an H atom inside the solid. In addition, two molecules as similar as atenolol and esmolol hydrochloride do not contain the same radicals after irradiation. These two conclusions drawn from the EPR results on β-blockers show clearly the importance of continuing the investigations on radiolytic mechanisms in solid-state drugs.

Original languageEnglish (US)
Pages (from-to)59-66
Number of pages8
JournalFree Radical Research
Volume38
Issue number1
DOIs
StatePublished - Jan 1 2004

Fingerprint

Electron Spin Resonance Spectroscopy
Atenolol
Paramagnetic resonance
Nadolol
Propranolol
Pharmaceutical Preparations
Tensors
Irradiation
Atoms
Molecules
esmolol

Keywords

  • HF-EPR
  • Irradiation
  • Phenoxyl radical
  • Q-band EPR
  • Solid-state drugs
  • X-band

ASJC Scopus subject areas

  • Biochemistry

Cite this

The use of multi-frequency EPR techniques to identify the radicals produced in irradiated β-blockers. / Engalytcheff, Alix; Kolberg, Matthias; Barra, Anne Laure; Andersson, K. Kristoffer; Tilquin, Bernard.

In: Free Radical Research, Vol. 38, No. 1, 01.01.2004, p. 59-66.

Research output: Contribution to journalReview article

Engalytcheff, Alix ; Kolberg, Matthias ; Barra, Anne Laure ; Andersson, K. Kristoffer ; Tilquin, Bernard. / The use of multi-frequency EPR techniques to identify the radicals produced in irradiated β-blockers. In: Free Radical Research. 2004 ; Vol. 38, No. 1. pp. 59-66.
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