1,3,8-Trimethylallantoin: a major caffeine metabolite formed by rat liver

Res Commun Chem Pathol Pharmacol. 1986 Jun;52(3):407-10.


The formation of 1,3,8-trimethylallantoin from caffeine is demonstrated for the first time in vitro in rat liver slices. This compound constitutes 15% of total in vitro metabolites. With this identification, all the metabolic pathways of caffeine shown in vivo (N-demethylation, oxidation to uric acids and formation of uracil and allantoin derivatives) are demonstrated in vitro.

MeSH terms

  • Allantoin / analogs & derivatives*
  • Allantoin / metabolism
  • Animals
  • Biotransformation
  • Caffeine / metabolism*
  • Carbon Radioisotopes
  • Chromatography, Thin Layer
  • In Vitro Techniques
  • Liver / metabolism*
  • Rats


  • Carbon Radioisotopes
  • Allantoin
  • Caffeine
  • 1,3,8-trimethylallantoin