^(177)Lu-NOTATATE的制备及初步生物学评价

Preparation and preliminary biological evaluation of ^(177)Lu-NOTATATE

目的探索^(177)Lu标记1,4,7-三氮杂环壬烷-1,4,7-三乙酸(NOTA)-D-苯丙氨酸1-酪氨酸3-苏氨酸-8-奥曲肽(TATE)的最佳条件,评价标记物的生物学性质并行小鼠显像。方法通过改变反应温度、pH值、反应时间等,实现^(177)Lu-NOTATATE的快速制备,确定最佳标记条件,测定其放化纯、体外稳定性、血浆蛋白结合率及脂水分配系数。取24只正常昆明小鼠,用随机数字表法分为6组,经尾静脉注射3.7 MBq^(177)Lu-NOTATATE后,分别于0.5、1、4、24 h及4、6 d处死,检测体内生物分布[每克组织百分注射剂量率(%ID/g)]。取6只正常小鼠,随机(方法同上)分为2组,分别给予11.1 MBq^(177)Lu-NOTATATE与^(177)Lu-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸(DOTA)TATE注射,于注射后1、2、3 h行SPECT平面显像。另取8只小鼠分4组(3.7、7.4、18.5 MBq^(177)Lu-NOTATATE和生理盐水注射)进行毒性实验研究。结果反应温度95~100℃、反应时间15 min、pH值为5为最佳标记条件。在该条件下,产物^(177)Lu-NOTATATE的标记率>98%,在人血清中放置24 h后放化纯仍>95%。血浆蛋白结合率为(58.6±1.9)%,脂水分布系数为0.048±0.014。在正常小鼠体内,放射性主要在肝、肾、脾浓聚,尤以肾浓聚较多[注射后0.5 h即达(29.120±1.204)%ID/g],在血液中分布少,并且迅速排泄。显像结果示,与^(177)Lu-DOTATATE比较,^(177)Lu-NOTATATE经肾排泄更快。毒性实验中,各组小鼠均未观察到明显损害,器官组织切片也未见明显损伤或炎性改变。结论确定了^(177)Lu-NOTATATE的最佳标记条件,标记产物理化性质及生物学性能良好且安全,经肾排泄快于^(177)Lu-DOTATATE;该研究为进一步的临床转化研究打下了基础。

Objective To explore the optimal labeling conditions of ^(177)Lu-1,4,7-triazacyclononane-1,4,7-triacetic acid(NOTA)-D-Phe1-Tyr3-Thr8-octreotide(TATE),and evaluate its biodistribution and imaging characteristics in mice.Methods The reaction temperature,pH,reaction time and other labeling conditions were changed to realize the rapid labeling of NOTATATE by ^(177)Lu.The optimal labeling conditions,radiochemical purity,in vitro stability,plasma protein binding rate,and lipid-water partition coefficient were determined.Twenty-four normal KM mice were divided into 6 groups by random number table method.After injected with 3.7 MBq ^(177)Lu-NOTATATE through tail vein,they were sacrificed at 0.5,1,4,24 h and 4,6 d respectively to research the biological distribution(injection dose rate per gram of tissue percentage,%ID/g).Six normal mice were randomly divided into 2 groups and injected with 11.1 MBq ^(177)Lu-NOTATATE and ^(177)Lu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid(DOTA)TATE,respectively.SPECT planar imaging was performed at 1,2,3 h after injection.Another 8 mice were divided into 4 groups,injected with 3.7,7.4,18.5 MBq ^(177)Lu-NOTATATE and saline respectively for an acute toxicity test.Results At pH 5 and reaction temperature between 95℃and 100℃for 15 min,the labeling rate could reach more than 98%.After being placed in human serum for 24 h,the radiochemical purity was still higher than 95%.The plasma protein binding rate of ^(177)Lu-NOTATATE was(58.6±1.9)%and the lipid-water partition coefficient was 0.048±0.014.In normal mice,the concentration of radioactivity is mainly in the liver,kidney and spleen,especially in the kidney(up to(29.120±1.204)%ID/g after 0.5 h of injection),which is less distributed in the blood and excreted rapidly.Compared with ^(177)Lu-DOTATATE,^(177)Lu-NOTATATE was excreted faster by the kidney.The toxicity study results revealed that no damage was observed in mice of each group,and no obvious damage or inflammatory changes were observed in organ tissue sections.Conclusions The optimal labeling condition of ^(177)Lu-NOTATATE were determined in this study.The physical,chemical,and biological properties of ^(177)Lu-NOTATATE were proved to be good and safe,and it was excreted faster by the kidney than ^(177)Lu-DOTATATE.The results of this study lay a foundation for further clinical transformation research.