The effect of ipriflavone and its main metabolites on theophylline biotransformation

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The effect of ipriflavone and its major metabolites, 7-hydroxy-isoflavone and 7-(1-carboxy-ethoxy)-isoflavone on theophylline metabolism was examined in vitro in human liver microsomes. The compounds inhibited the N-demethylation to 1- or 3-methylxanthine, the major pathway of theophylline metabolism. The effect showed concentration dependence. The oxidation of theophylline to 1,3-dimethyluric acid was slightly affected by ipriflavone and its metabolites and the effect was non-specific. Results indicate that the reduction of theophylline clearance by concomitant ipriflavone administration observed by Takahashi et al. is primarily due to an interaction of the inhibitory ipriflavone and/or its metabolites with cytochrome P450 enzyme(s) that mediate N-demethylation of theophylline.

Original languageEnglish
Pages (from-to)61-66
Number of pages6
JournalEuropean Journal of Drug Metabolism and Pharmacokinetics
Issue number1
Publication statusPublished - Jan 1 1996



  • Biotransformation
  • Interaction
  • Ipriflavone
  • Theophylline

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)

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