Preparation of 99mtc-Labeled L,L-Ethylenedicysteine Diethylester and Labeling to Leukocytes

鎝99m標誌半胱胺酸乙酯雙聚體之製備及白血球標誌之試驗

羅建苗(Jem-Mau Lo) ； 林國賢(Kuo-Shyang Lin) ； 高嘉鴻(Chia-Hung Kao) ； 王世楨(Shyh-Jen Wang)

《核子醫學雜誌》 12卷1期 (1999/03) Pp. 29-37

摘要

前言：L，L-ECD配位基係將L，L-乙烯雙半胱胺酸(L,L-ethylenedicysteine,L,L-EC)在含氯化氫氣體之乙醇中行酯化反應而得，此酯化反應之前驅物L，L-EC則由L-硫氮伍圜-4-羧酸(L-thiazo1idine-4-carboxylic acid)在液氨中經鈉還原而來。所得L，L-ECD經熔點、核磁共振譜、質譜及元素分析鑑定證實為高純度成品。鎝-99m與L，L-ECD之配位錯化反應係將1.5×10^(-3)M L，L-ECD加入於0.08 M甘露醇(mannito1)，0.8×10^(-3)M乙烯雙胺四醋酸鹽(EDTA)，1×10^(-4)M錫離子(Sn(superscript 2+))及pH 3-10之緩衝液等之混合物，然後加入50 MBq之過鎝酸鹽(99mT(下标 c)O(上标 -)4)之生理食鹽水溶液，振盪一分鐘後即得。此99mTc-L，L-ECD溶液經溶劑萃取、電泳動、薄層層析、高效益液態層析、及電化學分析等分析方法對其化學特性作了充分的鑑定。證實在pH 5-8溶液中99mTc-L，L-ECD確具不尋常之高度穩定性、中性及親脂性。方法：按上述配方在pH 7.4條件下，經冷凍乾燥製成之L，L-ECD之乾粉注射小瓶，經掺加500 MBq之99mT(下标 c)O(上标 -)4生理食鹽水溶液並振盪一分鐘，所得99mTc-L，L-ECD溶液進行兔子血液及人體血液之白血球標誌試驗。我們並取目前商品化之腦造影劑99mTc-d,1-HMPAO（英國Amersham公司製造）進行白血球標誌試驗以為參考。結果：試驗結果顯示，99mTc-L，L-ECD在人體白血球有顯著之標誌效率，其進入且停留在人體白血球之陷阱機轉(trapping mechanism)可能與其進入靈長類動物（人及猿猴類）之腦血液之機轉爲一致。另一方面，在兔子血液白血球中幾無標誌效果則顯示99mTc-L，L-ECD對非靈長動物白血球並無陷阱效應。

關鍵字

鎝—99m標誌—L ； L-ECD ； 白血球標誌

並列摘要

The ligand,L,L-ECD was synthesized by esterification of L,L-ethylenedicysteine(L,L-EC)in ethyl alcohol being catalyzed by hydrogen chloride gas. The precursor, L,L-EC used was produced beforehand by reduction of L-thiazolidine-t-carboxylic acid with sodium in liquid ammonia. The complexation of L,L-ECD with 99mTcwas carried out by adding approximately 50 MBq of99mTc-pertechnetate to a solution containing 1.5×10^(-3)ML,L-ECD,0.08 M mannitol,0.8×10^(-3)M EDTA,1×10^(-4)M Sn(superscript 2+)and the buffer solution with different pH ranging from 3 to 10.The mixture was vortexed for one minute. The 99mTc-L,L-ECD complex produced from the buffer solutions with pH ranging 5-8 was extraordinarily highly stable, neutral, and lipophilic .A freeze-dried kit of L,L-ECD was produced in accordance with the formulation mentioned above under the buffer solution specified at pH 7.4.The 99mTc-L,L-ECDsolution was obtained by reconstitution of the kit with500 MBq of 99mTc-Tc-pertechnetate in saline. The 99mTc-L,L-ECD solution was taken to label two sorts of leukocytes from rabbit blood and from human blood. For reference ,a current imaging agent,99mTc-d,I-HMPAO was prepared by reconstituting its kit(Amersham International plc.)with a similar quantity of 99mTc-Tc-pertechnetate saline solution and taken for the same biological characterization study as mentioned above for 99mTc-L,L-ECD.The results revealed that 99mTc-L,L-ECD has a significant labeling efficiency for human leukocytes, but little for the rabbit leukocytes. The retention mechanism of 99mTc-L,L-ECD in human leukocytes may be consistent with the retention in the brain of the primates. On the other hand, little retention of 99mTc-L,L-ECD was found in rabbit leukocytes indicaring that 99mTc-L,L-ECD exhibits no trapping effect on the leukocytes of the lower species of animals.

並列關鍵字

99mTc labeled ethylenedicysteine diethylester ； white blood cell label