摘要
目的:探索一种^(68)Ga标记四嗪探针(^(68)Ga-NOTA-Tz)的优化标记条件,并评价其体内外性质。方法:开展^(68)GaNOTA-Tz的标记条件优化实验,包括反应体系的p H值、温度、时间和前体用量等4种影响因素。利用放射性快速薄层色谱(Radio-i TLC)和放射性高效液相色谱(Radio-HPLC)测定^(68)Ga-NOTA-Tz的标记率和体外稳定性,并进行脂水分配系数log P、血浆蛋白结合率、BALB/c正常鼠血液半衰期和生物分布、以及在SMMC-7721移植瘤模型Micro PET/CT显像等体内外性质评价。结果:根据优化实验结果,^(68)Ga-NOTA-Tz最佳标记条件是反应体系p H=3.8、反应温度45℃、反应时间10 min、前体用量5 nmol,在此条件下其标记率大于95%。体外实验显示,^(68)Ga-NOTA-Tz在生理盐水和胎牛血清中的稳定性分别保持在95%和90%以上(4 h内),其脂水分配系数log P为-2.06±0.02,血浆蛋白结合率为20%左右(1.5 h内)。血液半衰期实验表明,^(68)Ga-NOTA-Tz的早期快速分布半衰期为1.1 min、终末缓慢清除半衰期为29.1 min。体内生物分布和肿瘤Micro PET/CT发现,^(68)Ga-NOTA-Tz主要分布于肝、胆、肾脏和膀胱等代谢器官,对应的%ID/g均较高,同时在肿瘤组织均匀分布,0.5、1.0、1.5 h时的%ID/gmean分别为1.6±0.11、1.3±0.15和1.3±0.12,与肌肉和心脏的较为接近。结论:本研究优化建立了四嗪探针^(68)Ga-NOTA-Tz的制备条件,其标记率高,具有良好的稳定性和亲水性,在体内能快速而均匀地分布至肿瘤组织,有利于其应用于基于体内生物正交点击反应的肿瘤预靶向PET/CT显像。
Objective:To explore the optimal radiolabeling conditions of^(68)Ga-labeled tetrazine probe(^(68)Ga-NOTA-Tz),and to evaluate it’s in vitro and in vivo properties.Methods:The optimization experiments of the radiolabeling conditions of^(68)Ga-NOTATz were carried out,including 4 influencing factors such as pH,temperature,time and precursor amount.The radiolabeling efficiency and in vitro stability of^(68)Ga-NOTA-Tz were determined by Radio-iTLC and Radio-HPLC and its lipid-water partition coefficient log P,plasma protein binding ratio,blood half-life and biodistribution in normal BALB/c mice,as well as MicroPET/CT imaging in SMMC-7721 xenograft tumor mouse model were evaluated.Results:According to the results of optimization experiments,the optimized radiolabeling conditions of^(68)Ga-NOTA-Tz were pH=3.8,temperature at 45℃,reaction time of 10 min,and precursor amount of 5.0 nmol and the radiolabeling efficiency under these conditions was above 95%.In vitro assays showed the stability of^(68)Ga-NOTA-Tz in saline and fetal bovine serum remained above 95%and 90%within 4.0 h,respectively,its log P was-2.06±0.02,and the plasma protein binding rate was about 20%within 1.5 h.The blood half-life tests of^(68)Ga-NOTA-Tz found the early rapid distribution half-life was 1.1 min and the terminal slow clearance half-life was 29.1 min.In vivo biodistribution and tumor MicroPET/CT imaging revealed that^(68)Ga-NOTA-Tz was mainly distributed in metabolic organs such as liver,gallbladder,kidney and bladder with relatively high%ID/g,and was homogeneously distributed in tumor lesion with%ID/gmean of 1.6±0.11,1.3±0.15 and 1.3±0.12 at 0.5,1.0 and 1.5 h,respectively,which were closer to those of muscle and heart.Conclusion:In this study,the radiolabeling conditions of^(68)Ga-NOTA-Tz were optimized with high radiolabeling efficiency,and it possessed good stability and hydrophilicity,and could rapidly and uniformly distributed into tumor lesion in vivo,which could benefit for its application into tumor pretargeted PET/CT imaging based on in vivo bioorthogonal click reaction.
作者
张丰盛
王撵
宋少莉
杨红
王明伟
ZHANG Fengsheng;WANG Nian;SONG Shaoli;YANG Hong;WANG Mingwei(Department of Nuclear Medicine,Fudan University Shanghai Cancer Center,Department of Oncology,Shanghai Medical College,Fudan University,Shanghai 200032,China;College of Chemistry and Materials Sciences,Shanghai Normal University,Shanghai 200234,China;Center for Biomedical Imaging,Fudan University,Shanghai 200032,China;Shanghai Engineering Research Center of Molecular Imaging Probes,Shanghai 200032,China)
出处
《肿瘤影像学》
2023年第5期445-452,共8页
Oncoradiology
基金
国家自然科学基金(21771041)。
