Automated radiosynthesis of 5-[11C]L-glutamine, an important tracer for glutamine utilization

Adam J. Rosenberg, Michael L. Nickels, Michael L. Schulte, H. Charles Manning

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Introduction: The natural amino acid L-Glutamine (Gln) is essential for both cell growth and proliferation. In addition to glucose, cancer cells utilize Gln as a carbon source for ATP production, biosynthesis, and as a defense against reactive oxygen species. The utilization of [11C]Gln has been previously reported as a biomarker for tissues with an elevated demand for Gln, however, the previous reports for the preparation of [11C]Gln were found to be lacking several crucial aspects necessary for transition to human production. Namely, the presence of unreacted precursor and the use of non-commercialized, custom built, reaction platforms. Herein, we report the development and utilization of methodology for the automated production of [11C]Gln that meets institutional criteria for human use. Methods: The preparation of [11C]Gln was carried out on the GE FX2N platform. Briefly, after trapping of [11C]HCN with a solution of CsHCO3 in DMF, the [11C]CsCN was reacted with a commercially available precursor. This intermediate was then purified by HPLC and deprotected/hydrolyzed under acidic conditions. Following pH adjustment, the product was filtered to give the desired [11C]Gln as a sterile injectable. The resulting product was then analyzed for quality assurance. Results: Automated production by this method reliably provides over 3.7 GBq (100 mCi) of [11C]Gln. The resulting final drug product was found to have a >99% radiochemical purity, <5% of D-Gln present, no detectable impurities, and the total preparation time was roughly 45 min from the end-of-bombardment. Conclusions: A fast, reliable and efficient automated radiosynthesis was developed using a commercially available module. Purifications used throughout allow for both a radiochemically and chemically pure final product solution of [11C]Gln.

Original languageEnglish
Pages (from-to)10-14
Number of pages5
JournalNuclear Medicine and Biology
Volume67
DOIs
StatePublished - Dec 2018

Keywords

  • Automated radiosynthesis
  • Carbon-11
  • Metabolism
  • PET
  • Radiopharmaceuticals
  • [C]Glutamine

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