The 13I-FP-β-CIT (2β-carbomethoxy-3β-(4-iodophenyl)tropane) was prepared by ourselves. Its partition coefficients were determined.
Kinetics of blood clearance in rabbits,
biodistribution in rats brains, toxicity test in mice as well as autoradiography in rat's brain, SPECT imaging in normal monkey's brain were studied. The partition coefficients were 15 and 28 at pH 7.0 and 7.4
respectively. The brain uptake in rats was rapid (0.78, 0.59 %ID/organ at 2 min, 2 h after injection respectively), the ratios of striatum/cerebellum, striatum /frontal cortex and striatum / hippocampus were 5.2,2.2 and 3.1 at 1 h in rat's brain. The uptake in striatum could be blocked by p-CFT, suggesting that 131I-FP-β-ClT binds to DAT specifically. The compound was rapidly cleared from rabbits' blood, taking only 2 min to reduce to half of the original concentration. The ratio of striatum/occipital cortex is 2.7 in autoradiography of rat's brain. l31l-FP-β-CIT concentrated in striatum in SPECT imaging in normal monkey. The ratio of striatum /cerebellum and striatum /occipital cortex were 5.4 and 6.0 respectively at 2 h. The test of toxicity showed that the dose received by mice was 750 times by human, proving the agent was safe. These results suggest that the compound is a good SPECT imaging agent for DAT.