Curcumin metal complexes showed widespread applications in medicine and can be exploited as a lead structure for developing new tracers for nuclear medicine application. Herein, the synthesis, chemical characterization and radiolabelling with gallium-68 and scandium-44 of two new targeting vectors based on curcumin scaffolds and linked to the chelators 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA) and 1,4-bis(carboxymethyl)-6-[bis(carboxymethyl)]amino-6-methylperhydro-1,4-diazepine (AAZTA) are reported. Synthesis of the precursors could be achieved with a 13% and 11% yield and radiolabelling generally afforded rapid incorporation under mild conditions (>95%). Stability in physiological media (~75% after 2 h in human blood for [68Ga]Ga-/[44Sc]Sc-AAZTA-PC21 and ~60% for [68Ga]Ga-NODAGA-C21, respectively) are generally enhanced if compared to the previously radiolabelled analogues. MSn fragmentation experiments showed high stability of the AAZTA-PC21 structure mainly due to the pyrazole derivatization of the curcumin keto-enol moiety and a more feasible radiolabelling was noticed both with gallium-68 and scandium-44 mainly due to the AAZTA-chelator properties. [68Ga]Ga-NODAGA-C21 showed the most favorable lipophilicity value (logD = 1.3). Due to these findings, both compounds appear to be promising candidates for the imaging of colorectal cancer, but further studies such as in vitro uptake and in vivo biodistribution experiments are needed.

中文翻译：

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基于姜黄素结构且与双功能螯合剂连接的镓68和scan 44标记的放射性示踪剂：潜在PET放射性示踪剂的合成和表征。

姜黄素金属配合物在医学中显示出广泛的应用，并且可以被用作开发用于核医学应用的新示踪剂的先导结构。在本文中，基于姜黄素支架并与螯合剂1,4,7-三氮杂环壬烷，1-戊二酸-4,7-乙酸连接的两个新的靶向载体的镓68和scan44的合成，化学表征和放射性标记据报道（NODAGA）和1，4-双（羧甲基）-6- [双（羧甲基）]氨基-6-甲基过氢-1,4-二氮杂（AAZTA）。可以以13％和11％的产率实现前体的合成，并且放射性标记通常可在温和条件下（> 95％）迅速掺入。在生理介质中的稳定性（[68Ga] Ga-/ [44Sc] Sc-AAZTA-PC21在人血中2小时后约为75％，[68Ga] Ga-NODAGA-C21为约60％，如果与先前放射性标记的类似物相比，则通常被增强。MSn碎片实验显示，主要是由于姜黄素酮-烯醇部分的吡唑衍生化，AAZTA-PC21结构具有很高的稳定性，而镓68和scan 44均由于AAZTA-螯合剂的性质而被认为是更可行的放射性标记。[68Ga] Ga-NODAGA-C21显示出最有利的亲脂性值（logD ＝ 1.3）。由于这些发现，这两种化合物似乎都是大肠癌成像的有希望的候选物，但是还需要进一步的研究，例如体外摄取和体内生物分布实验。MSn碎片实验显示，主要是由于姜黄素酮-烯醇部分的吡唑衍生化，AAZTA-PC21结构具有很高的稳定性，而镓68和scan 44均由于AAZTA-螯合剂的性质而被认为是更可行的放射性标记。[68Ga] Ga-NODAGA-C21显示出最有利的亲脂性值（logD ＝ 1.3）。由于这些发现，这两种化合物似乎都是大肠癌成像的有希望的候选物，但是还需要进一步的研究，例如体外摄取和体内生物分布实验。MSn碎片实验显示，主要是由于姜黄素酮-烯醇部分的吡唑衍生化，AAZTA-PC21结构具有很高的稳定性，而镓68和scan 44均由于AAZTA-螯合剂的性质而被认为是更可行的放射性标记。[68Ga] Ga-NODAGA-C21显示出最有利的亲脂性值（logD ＝ 1.3）。由于这些发现，这两种化合物似乎都是大肠癌成像的有希望的候选物，但是还需要进一步的研究，例如体外摄取和体内生物分布实验。