Synthesis of (4‐[ 18 F]fluorophenyl)triphenylphosphonium as a potential imaging agent for mitochondrial dysfunction

Tetraphenylphosphonium (TPP) cation is able to function as a molecular probe for monitoring mitochondrial disease. The F‐18 labeled TPP, (4‐[ 18 F]fluorophenyl) triphenylphosphonium ( 18 FTPP), was therefore developed as a PET radioligand for in vivo molecular imaging of mitochondrial dysfunction. 18 FTPP was synthesized via direct nucleophilic substitution of no‐carrier‐added [ 18 F]fluoride with the precursor 4‐nitrophenyltriphenylphosphonium. After purification by HPLC, the average radiochemical yield was determined to be 10–15% and the specific activity was >500 Ci/mmol at the end of synthesis. The total synthesis time was within 60 min, and the radiochemical purity of the 18 FTPP was above 95%.