Fig. 3.
First-order kinetic plots were obtained in vitro for hydrolysis of FET prodrugs in rat (A) and human (B) blood at 37 °C. It was clearly demonstrated that FET-Gly ([18F]2) and FET-Ala ([18F]3) showed excellent in vitro hydrolysis – releasing FET ([18F]1) rapidly. However, the Nacetyl derivative of FET, AcFET ([18F]4), exhibited a very slow rate.