Carbon-11 labelled ketamine - Synthesis, distribution in mice and PET studies in baboons

C. Y. Shiue, S. Vallabhahosula, A. P. Wolf, S. L. Dewey, J. S. Fowler, D. J. Schlyer, C. D. Arnett, Y. G. Zhou

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

No-carrier-added (NCA) [11C](±)-ketamine (2a) and its enantiomers (+)-2b and (-)-2c were synthesized by methylation of the corresponding norketamine (1a-c) with [11C]H3I in an overall radiochemical yield of 20% (EOB) with specific activities of 0.35-0.45 Ci/μmole at EOB in a synthesis time of 40 min from EOB. Compound 2a was metabolized rapidly in mouse brain and labeled metabolites appeared in baboon plasma. PET studies of compounds 2a-c in a baboon showed that influx of compounds 2a-c into the brain was high for the first few min but radioactivity then declined rapidly. Although the retention of radioactivity in the baboon striatum was not significantly different for 2a-c 20 min post-injection, graphical analysis of time activity data for each enantiomer and for the racemate in baboon striatum suggested that (+)-ketamine may interact with receptors slightly more effectively than its (-)-enantiomer or racemate. However, due to its rapid metabolism in the brain and a similar uptake in the striatum and cerebellum, [11C]ketamine may not be an ideal tracer for studying NMDA receptor with PET.

Original languageEnglish
Pages (from-to)145-150
Number of pages6
JournalNuclear Medicine and Biology
Volume24
Issue number2
DOIs
StatePublished - 1997
Externally publishedYes

Keywords

  • 2-(o-chlorophenyl)-2-(methylamino)cyclohexanon e
  • Baboon
  • Ketamine
  • Mouse brin
  • [C]ketamine

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