1. Academic Validation
  2. Benzydamine N-oxygenation as a measure of flavin-containing monooxygenase activity

Benzydamine N-oxygenation as a measure of flavin-containing monooxygenase activity

  • Methods Mol Biol. 2006;320:157-62. doi: 10.1385/1-59259-998-2:157.
Catherine K Yeung 1 Allan E Rettie
Affiliations

Affiliation

  • 1 Department of Medicinal Chemistry, University of Washington, Seattle, USA.
Abstract

Benzydamine is a nonsteroidal anti-inflammatory drug that undergoes flavin-containing monooxygenase (FMO)-dependent metabolism to a stable N-oxide. This metabolite can be quantified with high specificity and sensitivity by using a simple reverse-phase high-performance liquid chromatography (HPLC) assay with fluorescence detection. Studies with recombinant FMO Enzymes demonstrate that FMOI and FMO3 are the primary catalysts of benzydamine N-oxygenation, with minimal contributions from Cytochrome P450 enzymes. Investigations conducted with human liver microsomes confirm that FMO3, in large part, is responsible for benzydamine N-oxide formation in this tissue. These features render benzydamine a useful in vitro probe for FMO activity in a wide range of tissues and cell types. In addition, benzydamine appears to be a suitable in vivo probe for human liver FMO3. This chapter provides a detailed account of the experimental protocol for determining rates of formation of benzydamine N-oxide by FMO-containing Enzyme fractions.

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