PURPOSE: 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide labeled with [(18)F]-fluorine ([(18)F]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 [(18)F]EF5 have been demonstrated. Our purpose was to increase the specific radioactivity of [(18)F]EF5 to enable to study the pharmacokinetics at trace level. PROCEDURES: [(18)F]EF5 was synthesized using high specific radioactivity electrophilic [(18)F]F(2) as labelling reagent. Biodistribution of [(18)F]EF5 was determined in a prostate tumor mouse model, and formation of radiolabelled metabolites was studied in mouse, rat and human plasma. RESULTS: On average, 595 ± 153 MBq of [(18)F]EF5 was produced. Specific radioactivity was 6.6 ± 1.9 GBq/μmol and the radiochemical purity exceeded 99.0%. [(18)F]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. CONCLUSIONS: [(18)F]EF5 was synthesized by electrophilic labelling with high quality and high yields. Pharmacokinetics of [(18)F]EF5 was determined at trace level in several species. Our results suggest that the trace-level approach does not affect the biodistribution of [(18)F]EF5. Extensive metabolism was seen in mouse.
PURPOSE:2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide labeled with [(18)F]-fluorine ([(18)F]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 [(18)F]EF5 have been demonstrated. Our purpose was to increase the specific radioactivity of [(18)F]EF5 to enable to study the pharmacokinetics at trace level. PROCEDURES: [(18)F]EF5 was synthesized using high specific radioactivity electrophilic [(18)F]F(2) as labelling reagent. Biodistribution of [(18)F]EF5 was determined in a prostate tumormouse model, and formation of radiolabelled metabolites was studied in mouse, rat and human plasma. RESULTS: On average, 595 ± 153 MBq of [(18)F]EF5 was produced. Specific radioactivity was 6.6 ± 1.9 GBq/μmol and the radiochemical purity exceeded 99.0%. [(18)F]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. CONCLUSIONS: [(18)F]EF5 was synthesized by electrophilic labelling with high quality and high yields. Pharmacokinetics of [(18)F]EF5 was determined at trace level in several species. Our results suggest that the trace-level approach does not affect the biodistribution of [(18)F]EF5. Extensive metabolism was seen in mouse.
Authors: Gaber Komar; Marko Seppänen; Olli Eskola; Paula Lindholm; Tove J Grönroos; Sarita Forsback; Hannu Sipilä; Sydney M Evans; Olof Solin; Heikki Minn Journal: J Nucl Med Date: 2008-11-07 Impact factor: 10.057
Authors: Ludwig Dubois; Willy Landuyt; Lieselotte Cloetens; Anne Bol; Guy Bormans; Karin Haustermans; Daniel Labar; Johan Nuyts; Vincent Grégoire; Luc Mortelmans Journal: Eur J Nucl Med Mol Imaging Date: 2008-08-09 Impact factor: 9.236
Authors: L S Ziemer; S M Evans; A V Kachur; A L Shuman; C A Cardi; W T Jenkins; J S Karp; A Alavi; W R Dolbier; C J Koch Journal: Eur J Nucl Med Mol Imaging Date: 2002-11-23 Impact factor: 9.236
Authors: Gaber Komar; Kaisa Lehtiö; Marko Seppänen; Olli Eskola; Helena Levola; Paula Lindholm; Hannu Sipilä; Jan Seppälä; Reidar Grénman; Olof Solin; Heikki Minn Journal: Eur J Nucl Med Mol Imaging Date: 2014-06-05 Impact factor: 9.236