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Tracer Level Electrophilic Synthesis and Pharmacokinetics of the Hypoxia Tracer [F-18]EF5

På svenska

Author

  • Olli Eskola
  • Tove J. Gronroos
  • Sarita Forsback
  • Johanna Tuomela
  • Gaber Komar
  • Jorgen Bergman
  • Pirkko Härkönen
  • Merja Haaparanta
  • Heikki Minn
  • Olof Solin

Summary, in English

2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide labeled with [F-18]-fluorine ([F-18]EF5), a promising tracer for tumor hypoxia, has previously been synthesized in low yields and low specific radioactivity. In pharmacokinetic evaluations, in the presence of non-radioactive EF5, a uniform and low background uptake and high in vivo stability of [F-18]EF5 have been demonstrated. Our purpose was to increase the specific radioactivity of [F-18]EF5 to enable to study the pharmacokinetics at trace level. [F-18]EF5 was synthesized using high specific radioactivity electrophilic [F-18]F-2 as labelling reagent. Biodistribution of [F-18]EF5 was determined in a prostate tumor mouse model, and formation of radiolabelled metabolites was studied in mouse, rat and human plasma. On average, 595 +/- 153 MBq of [F-18]EF5 was produced. Specific radioactivity was 6.6 +/- 1.9 GBq/mu mol and the radiochemical purity exceeded 99.0%. [F-18]EF5 was distributed uniformly in tissues, with highest uptake in liver, kidney, and intestine. Several radiolabelled metabolites were detected in mouse plasma and tissues, whereas low amounts of metabolites were detected in human and rat plasma. [F-18]EF5 was synthesized by electrophilic labelling with high quality and high yields. Pharmacokinetics of [F-18]EF5 was determined at trace level in several species. Our results suggest that the trace-level approach does not affect the biodistribution of [F-18]EF5. Extensive metabolism was seen in mouse.

Publishing year

2012

Language

English

Pages

205-212

Publication/Series

Molecular Imaging and Biology

Volume

14

Issue

2

Document type

Journal article

Publisher

Springer

Topic

  • Radiology, Nuclear Medicine and Medical Imaging

Keywords

  • Hypoxia
  • Biodistribution
  • Metabolism
  • PET
  • [F-18]EF5
  • Electrophilic synthesis

Status

Published

ISBN/ISSN/Other

  • ISSN: 1536-1632