Automated synthesis of 18F-fluoropropoxytryptophan for amino acid transporter system imaging.

Objective: This study was to develop a cGMP grade of [(18)F]fluoropropoxytryptophan ((18)F-FTP) to assess tryptophan transporters using an automated synthesizer.

Methods: Tosylpropoxytryptophan (Ts-TP) was reacted with K(18)F/kryptofix complex. After column purification, solvent evaporation, and hydrolysis, the identity and purity of the product were validated by radio-TLC (1M-ammonium acetate : methanol = 4 : 1) and HPLC (C-18 column, methanol : water = 7 : 3) analyses.

Synthesis and biological evaluation of O-[3-18F-fluoropropyl]-α-methyl tyrosine in mesothelioma-bearing rodents.

Radiolabeled tyrosine analogs enter cancer cells via upregulated amino acid transporter system and have been shown to be superior to (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) in differential diagnosis in cancers. In this study, we synthesized O-[3-(19)F-fluoropropyl]-α-methyl tyrosine ((19)F-FPAMT) and used manual and automated methods to synthesize O-[3-(18)F-fluoropropyl]-α-methyl tyrosine ((18)F-FPAMT) in three steps: nucleophilic substitution, deprotection of butoxycarbonyl, and deesterification. Manual and automated synthesis methods produced (18)F-FPAMT with a radiochemical purity >96%.