Variation in glucuronidation of lamotrigine in human liver microsomes

U. A. Argikar, Rory P Remmel

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Lamotrigine (LTG), a diaminotriazine anti-epileptic, is principally metabolized at the 2-position of the triazine ring to form a quaternary ammonium glucuronide (LTGG) by uridine glucuronosyl transferease (UGT) 1A3 and UGT1A4. It has been hypothesized that glucuronidation of anti-epileptic drugs is spared with age, despite a known decrease in liver mass, based on older studies with benzodiazepines such as lorazepam. To examine this, the formation rates of LTGG formation were measured by liquid chromatography-mass spectrometry (LC-MS) in a bank of human liver microsomes (HLMs) obtained from younger and elderly donors at therapeutic concentrations. The formation rate of LTGG was not significantly different in HLMs obtained from younger and elderly subjects. A four- to five-fold variation for the formation of LTGG was observed within each microsomal bank obtained from elderly and younger donors, and the range of LTGG formation was observed to be 0.150.78nmoles min-1 mg-1 of protein across the entire set of HLMs (n36, elderly and younger HLMs). UGT1A4 and UGT1A3 catalysed the formation of LTGG with an intrinsic clearances of 0.28 and 0.02μl min-1 mg-1 protein, respectively. UGT2B7 and UGT2B4 showed no measurable activity. No correlation was observed across the HLM bank for glucuronidation of LTG and valproic acid (a substrate for multiple UGT isoforms including UGT1A4).

Original languageEnglish (US)
Pages (from-to)355-363
Number of pages9
JournalXenobiotica
Volume39
Issue number5
DOIs
StatePublished - Nov 9 2009

Fingerprint

Liver Microsomes
Liver
Uridine
Tissue Donors
Lorazepam
Triazines
Glucuronides
Valproic Acid
Benzodiazepines
Ammonium Compounds
Liquid Chromatography
Liquid chromatography
Mass Spectrometry
Protein Isoforms
Proteins
Mass spectrometry
lamotrigine
Pharmaceutical Preparations
Substrates

Keywords

  • Anti-epileptic
  • Glucuronidation
  • Lamotrigine
  • Uridine glucuronosyl transfereases (UGTs)
  • Valproic acid

Cite this

Variation in glucuronidation of lamotrigine in human liver microsomes. / Argikar, U. A.; Remmel, Rory P.

In: Xenobiotica, Vol. 39, No. 5, 09.11.2009, p. 355-363.

Research output: Contribution to journalArticle

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