Synthesis and in vivo stability studies of [18F]-zwitterionic phosphonium aryltrifluoroborate/indomethacin conjugates

With the goal of developing new positron emission tomography (PET) probes for imaging inflammation in cancer tumours, we have conjugated zwitterionic phosphonium aryltrifluoroborates as fluoride captors with indomethacin, a known cyclooxygenase 2 inhibitor. The resulting conjugates have been radiolabeled by F-18-F-19 isotopic exchange in aqueous solutions. NMR studies combined with in vivo data show that the nature of the phosphonium substituents plays an important role on the stability of the radiotracers.