18F Labeled benzimidazole derivatives as potential radiotracer for positron emission tomography (PET) tumor imaging Original Research Article

This article reported the synthesis and bioevaluation of two [18F] labeled benzimidazole derivatives, 4-(5-(2-[18F] fluoro-4-nitrobenzamido)-1-methyl-1H-benzimidazol-2-yl) butanoic acid ([18F] FNBMBBA, [18F]a1) and 3-(2-fluoroethyl)-7-methyl-2-propyl-3H-benzimidazole-5-carboxylic acid ([18F] FEMPBBA, [18F]b1) for PET tumor imaging. The preparation [18F] FEMPBBA was completed in 1 h with overall radiochemical yield of 50–60% (without decay corrected). Biodistribution assay in S180 tumor bearing mice of both compounds were carried out, and the results are both meaningful. [18F] FEMPBBA which can be taken as a revision of [18F] FNBMBBA got an excellent result, and has significant advantages in some aspects compared with L-[18F] FET and [18F]-FDG in the same animal model, especially in tumor/brain uptake ratio. The tumor/brain uptake ratio of [18F] FEMPBBA gets to 4.81, 7.15, and 9.8 at 30 min, 60 min and 120 min, and is much higher than that of L-[18F] FET (2.54, 2.92 and 2.95) and [18F]-FDG (0.61, 1.02, 1.33) at the same time point. The tumor/muscle and tumor/blood uptake ratio of [18F] FEMPBBA is also higher than that of L-[18F] FET at 30 min and 60 min. This result indicates compound [18F] FEMPBBA is a promising radiotracer for PET tumor imaging.