The radiosynthesis and radiopharmacological evaluation of 3-[4′-[¹⁸F]fluorobenzylidene]indolin-2-one, a derivative of tyrosine kinase inhibitor SU5416, is described. The radiosynthesis was accomplished by Knoevenagel condensation of 4-[¹⁸F]fluorobenzaldehyde with oxindole in a remotely controlled synthesis module. The reaction conditions were optimized through screening the influence of different bases on the radiochemical yield. The radiotracer was obtained after a two-step labelling procedure in 4% decay-corrected radiochemical yield at a specific activity of 48–61 GBq/μmol within 90 min. The radiochemical purity after semi-preparative HPLC purification exceeded 98%.

The biodistribution was studied in Wistar rats. After distribution the radiotracer was rapidly accumulated in the adrenals, liver and kidneys, however, it was cleared from these and the most other organs. Only the adipose tissue remained the activity over 60 min. Unexpected high transient uptake was observed in the brain, pancreas, heart and lung. The fast clearance of 3-[4′-[¹⁸F]fluorobenzylidene]indolin-2-one was caused by excretion, approximately one half each was renal and biliary excreted and the other part cleared by metabolic processes. In arterial blood plasma two more polar metabolites were found by radio-HPLC. After 20 min post-injection, only 12% of intact radiotracer has been detected. Consequently, in small animal PET studies with FaDu tumour bearing mice no specific uptake in the tumours could be observed.

描述了酪氨酸激酶抑制剂SU5416的衍生物3- [4'-[ ¹⁸ F]氟亚苄基]吲哚-2-酮的放射合成和放射药理学评估。放射性合成是通过在遥控合成模块中4- [ ¹⁸ F]氟苯甲醛与羟吲哚的Knoevenagel缩合完成的。通过筛选不同碱对放射化学收率的影响，优化了反应条件。经过两步标记程序后，放射性示踪剂以90％的比活度为48-61 GBq /μmol进行了4％衰减校正的放射化学收率。半制备型HPLC纯化后的放射化学纯度超过98％。

在Wistar大鼠中研究了生物分布。分布后，放射性示踪剂迅速聚集在肾上腺，肝脏和肾脏中，但已从这些器官和大多数其他器官清除了。在60分钟内只有脂肪组织保持活性。在脑，胰腺，心脏和肺部观察到意外的高瞬时摄取。3- [4'-[ ^18]的快速间隙F]氟亚苄基]吲哚啉-2-酮是由排泄引起的，大约一半被肾脏和胆汁排泄，另一部分则通过代谢过程清除。通过放射-HPLC在动脉血浆中发现了另外两种极性代谢产物。注射后20分钟后，仅检测到完整放射性示踪剂的12％。因此，在携带FaDu肿瘤的小鼠的小动物PET研究中，未观察到肿瘤的特异性摄取。