A novel thymidine isocyanide (CN-TdR) functionalized at the N3 position of thymidine was synthesized and then radiolabelled with ^99mTc(I) and [^99mTc(I)(CO)₃]⁺ cores to produce [^99mTc(CN-TdR)₆]⁺ and [^99mTc(CO)₃(CN-TdR)₃]⁺, respectively. Both of them were prepared with high radiochemical purity and were stable over 6 h in saline at ambient temperature and in serum at 37 °C. The partition coefficient results demonstrated that they were hydrophilic. The cell internalization studies showed that their uptake might be mediated by nucleoside transporters. Biodistribution of these complexes in mice bearing the S180 tumor showed that they accumulated in the tumor with high uptake and cleared rapidly from blood and muscles, producing high tumor/blood and tumor/muscle ratios. Between them, [^99mTc(CN-TdR)₆]⁺ exhibited advantages concerning a higher tumor uptake, tumor/blood ratio and tumor/muscle ratio at 60 min post-injection. Single photon emission computed tomography imaging studies showed that there was a clear accumulation in tumor sites, suggesting that [^99mTc(CN-TdR)₆]⁺ could be a promising candidate for tumor imaging.

中文翻译：

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新型 99mTc 标记的胸苷异氰化物复合物：放射合成和作为潜在肿瘤成像示踪剂的评估

合成了一种在胸苷N3位功能化的新型胸苷异氰化物（CN-TdR），然后用^99m Tc( I ) 和 [ ^99m Tc ( I )(CO) ₃ ] ⁺核心进行放射性标记，产生[ ^99m Tc(CN-TdR) ) ₆ ] ⁺和[ ^99m Tc(CO) ₃ (CN-TdR) ₃ ] ⁺，分别。两者均具有高放射化学纯度，并且在环境温度的盐水和 37°C 的血清中稳定超过 6 小时。分配系数结果表明它们是亲水性的。细胞内化研究表明，它们的摄取可能是由核苷转运蛋白介导的。这些复合物在携带 S180 肿瘤的小鼠中的生物分布表明，它们在肿瘤中以高摄取量积累，并从血液和肌肉中迅速清除，产生高肿瘤/血液和肿瘤/肌肉比率。其中，[ ^99m Tc(CN-TdR) ₆ ] ⁺在注射后 60 分钟时表现出较高的肿瘤摄取、肿瘤/血液比率和肿瘤/肌肉比率的优势。单光子发射计算机断层扫描成像研究表明，肿瘤部位有明显的积累，表明[ ^99m Tc(CN-TdR) ₆ ] ⁺可能是肿瘤成像的有希望的候选者。