Synthesis, radiolabeling and animal studies of [131I]MPPI: A 5-HT1A imaging agent

The synthesis and biological evaluation of serotonin (5-HT1A) imaging agent [131I]-4-iodo-N-{2-[4-(2-methoxyphenyl)-piperazin-1-yl]-ethyl}-N-pridin-2-yl-benzamide ([131I]MPPI) are reported. The chemical structure of aimed compound and intermediates were confirmed by IR, 1HNMR, and MS. Radiochemical purity was above 99% determined by TLC. Biodistribution of [131I]MPPI in rats displayed high uptake in hippocampus and low uptake in cerebellum. The ratio of the uptake of [131I]MPPI in hippocampus to that in cerebellum was 2.90 at 30 min post injection. The radioactivity in thyroid was 0.069 and 0.128% ID/g organ at 5 min and 120 min,respectively, and it was increased with time, which suggests that in vivo deiodination may be the major route of metabolism. Ex vivo autoradiography of brain section displayed significant decrease of radioactivity in hippocampus when pretreated with 8-OH-DPAT, a selective 5HT1A agonist, compared with control. These findings strongly suggested that 131I-MPPI could be used as an in vivo marker for studies of pharmacology of the 5-HT1A receptor system in animals.     

Synthesis, radiolabeling and animal studies of [~(131)I]MPPI: A 5-HTB_(1A) imaging agent

1 Introduction In the last two decades, considerable progress has been made in the understanding of the central nervous system (CNS) serotonin system. It is an important neurotransmission network that regulates various physiological functions and behavior, including anxi-ety and affective states.P[1-3]P The family of receptors activated by the neurotransmitter serotonin has been divided into at least seven classes (5-HTB1-7B), some of them further subdivided into different subtypesP[4, 5]P…     

~(18)F标记的白藜芦醇衍生物的合成及作为β-淀粉样斑块显像剂的初步评价

设计并合成四种白藜芦醇衍生物,以评价其用于Aβ-斑块PET显像的可能性。通过化学合成得到四种白藜芦醇衍生物的前体化合物和参比化合物;使用参比化合物测定其与Aβ1-42蛋白聚集体的体外结合性;经[~(18)F]亲核取代反应对具有较高亲和力的化合物进行放化标记,并进行体外稳定性、脂水分配系数、生物分布等的测定。体外竞争结合实验显示化合物(E)-1-(3,5-二甲氧基苯乙烯基)-4-(2-(2-(2-氟乙氧基)乙氧基)乙氧基)苯([~(19)F]F-7)具有中度的结合性(Ki=43.76nmol/L);[~(18)F]F-7的标记时间为32min,放化产率(未校正)为(23±2)%,经SEP PAK C18柱纯化后放化纯度大于95%,且在生理盐水中的稳定性大于3h,具有较好的脂溶性(lg P=3.08);生物分布实验显示化合物[~(18)F]F-7具有较快的脑清除,注射后2min和60min的脑摄取分别为(0.55±0.05)%ID/g和(0.06±0.01)%ID/g,清除比达到9。化合物[~(18)F]F-7是一种潜在的β-淀粉样斑块PET显像剂。     

Preparation and BiologicalEvaluation of Re/99Tcm(CO)3+-diphenyldiazeneDerivative as Candidates for Imaging Aβ Plaques in the Brain

To develop the non-invasiveand diagnostic agents for Alzheimer’s disease (AD), ⁹⁹Tc^m(CO)₃⁺-L(L: (E)-2-(4-((4-(dimethylamino)phenyl)diazenyl)phenylamino)acetic acid, adiphenyldiazene derivative) was prepared,radiochemical purity was above 95%. Initialautoradiography results suggested that ⁹⁹Tc^m(CO)₃⁺-Lshowed selective binding to the Aβ plaque-like structures in the brain section from theAD transgenic mice (Tg C57, APP, PS1 12-month-old), further, ⁹⁹Tc^m(CO)₃⁺-Lshowed the same binding sites with fluorescence stained by Re(CO)₃⁺-L.Biodistribution of ⁹⁹Tc^m(CO)₃⁺-L innormal mice demonstrated low uptake in brain (5 min: （0.52 ±0.11)% ID/g）whilst slow clearance from the brain tissues at 120 min post-injection (0.28 ± 0.04)%ID/g. The corresponding Re analogue was alsosynthesized, and the nature of its lowest electronically excited state wasdetermined by studies of the UV-vis absorption and fluorescence emissionproperties at room temperature. In addition, the fluorescent staining of the Re-complexwas performed in comparison to Thioflavin-T and autoradiography results of ⁹⁹Tc^m(CO)₃⁺-L.In conclusion, these results are encouraging for further exploration of ⁹⁹Tc^m(CO)₃⁺-Las a SPECT imaging agent for Aβplaques in the AD brain.     

5-羟色胺转运蛋白显像剂~(11)C-DASB的自动化合成及Micro PET/CT显像

目的:自动化合成5-羟色胺转运蛋白显像剂11 C-DASB并进行大鼠Micro PET/CT显像;方法:通过改变甲基化试剂、溶解前体溶剂及反应条件,得到优化的标记条件作为碳-11多功能合成模块的输入参数,进行自动化合成11 C-DASB,大鼠静脉注射11 C-DASB 45 min后进行显像;结果:采用11 C-CH3-Triflate作为甲基化试剂,通入新配制的含1mg去甲基DASB前体的500μL DMSO溶液内,80℃下加热2min,标准率为63.7%,大鼠显像表明,11 C-DASB特异性的浓聚于SERT富集区域;结论:经优化,11 C-DASB自动化合成可得到较高产率,大鼠显像表明,其特异性浓聚于SERT富集区域,有望作为5-羟色胺转运蛋白显像剂。     

^131I—nor—β—CIT的制备及其大鼠体内分布

合成了2β－甲酯基－3β－（4‘－碘苯基）去甲基托烷（nor-β-CIT)及标记前体2β－甲酯基－3β-（4‘-（三丁基锡）苯基）去甲基托烷。nor-β-CIT及中间体的IR、MS、HNMR、旋光分析等鉴定数据与结构相符。由标记前体制备^131I-nor-β-CIT,标记率（80－90）％,萃取后放化纯度＞95％。大鼠体内分布表明,^131I-nor-β-CIT能很快进脑,且清除较慢（注药后5min、30min和4h时脑的放射性摄取比分别为2．30、2．54和1．22％ID）。丘脑、中脑、海马和额叶表现出较高的放射性摄取,注药后的1h达到最大值（分别为1．77、1．78、1．54和2．13％ID）。额叶的摄取大于颞叶和顶叶（1h时的放射性摄取分别咪2．13、1．92、1．87％ID）,与5－HTT在脑中的分布一致。     

Semi-automated synthesis, validation and microPET imaging of 18F-FP-DTBZ as a vesicular monoamine transporter ligand

This work was to develop a semi-automated synthesis of 18F-9-fluoropropyl-9-desmethyl-DTBZ (18F-FP-DTBZ) and validate its potential as a vesicular monoamine transporter 2 (VMAT2) ligand.18F-FP-DTBZ was synthesized by a semi-automated procedure in a 21-35% yield without decay correction and with a radiochemical purity of >98%.Bioistribution in rats exhibited a favorable brain uptakes of the ligand (0.31±0.04 ID% at 60min post injection,n=8).The highest radioactivity located in VMAT2 enriched striatal tissue.The target-to-nontarget ratio (striatum/cerebellum,ST/CB) was 4.81±0.84.Blocking studies implied that striatum uptake could be blocked by DTBZ (a VMAT2 inhibitor) but could not by CFT (a dopamine transporter inhibitor).MicroPET imaging with 18F-FP-DTBZ in normal rats gave high quality images in which high radioactivity were observed in the striatal tissue.Time-and-activity curves revealed good retention in the target (striatum) and rapid clearance in the background (cerebellum),which resulted in a maximum ST/CB ratio of 5.08±0.81 (n=3) in 80-120min.By contrast,the 6-hydroxydopamine unilateral lesioned rats gave asymmetrical striata images with higher 18F-FP-DTBZ concentration on the unlesioned side (unlesioned-ST/CB=5.21±0.38,n=3) than the lesioned (lesioned-ST/CB=2.34±0.51).The results validated that 18F-FP-DTBZ is a favorable PET ligand binding to VMAT2.     

红景天苷的碘标记及其在小鼠体内的分布

通过131碘标记红景天苷以探索红景天苷在神经母细胞(SH-SY5Y)中的摄取及在小鼠体内的代谢分布.采用氯胺-T法对红景天苷进行131碘标记;以聚酰胺薄膜为支持介质、V三氯甲烷:V甲醇:V丙酮:V水=6:3:1:1的下层液为展开剂,测定标记率及标记物放化纯;分析神经母细胞SH-SY5Y及肿瘤细胞MCF-7对131I-红景天苷的摄取;KM小鼠尾静脉注射131I-红景天苷(1.85 MBq/只,n=5),于5、10、30、60、120、240 min分别取心、肝、肺、肾、脾、肌、骨、脑、肠、血,称重、计数,计算每克组织百分注射剂量率(%ID/g).结果表明,131I-红景天苷标记率达98%,其放化纯在1、4、20 d分别为98.5%、97.3%、97.1%;SH-SY5Y对131I-红景天苷基本无摄取,在0.5-4 h内摄取维持在0.035%左右,而MCF-7则为0.1%;131I-红景天苷在体内主要通过肝代谢、肾排泄,其中肝和肾5 min%ID/g组织分别为7.71%和11.32%,4 h则分别下降为0.36%和0.3%;血液中清除也较快,5 min时为6.41%,4 h为0.35%;在脑中虽分布较少,但清除较慢,5 min时为0.27%,4 h为0.11%;在心、肺、脾、肌、骨及肠中分布不多.结论是,碘标红景天苷标记率高,标记物稳定;神经母细胞对131I-红景天苷基本无摄取.     

Aβ斑块显像剂苯并噻唑衍生物的11C标记

为寻找合适的碳-11标记的在体A斑块显像剂,根据文献合成了苯并噻唑（BTA）的前体：（对胺基苯）苯并噻唑类（APBT）,并用改良法碳-11碘代甲烷标记了APBT;柱色层法测标记率;改良法碳-11标记BTA的效率为58%。本文对碳-11标记方法和放射性标记率的方法作了改过,明显提高了标记效率,改进后的标记率测量方法简单、有效;正常小鼠的脑摄取[11]-BTA-1较高,2min全脑摄取为3.810.34%/ID;非特异区清除快,2min/30min摄取比达到10。[11]-BTA-1是一个有希望用于早老痴呆诊断的A斑块显像剂。     

一种潜在5-HT1A脑受体显像剂99Tcm-Bicine/HYNIC-MPP2的制备及其生物性能

优化合成了含有1-(2-甲氧基苯基)哌嗪(MPP)结构的配体2-(4-(2-甲氧基苯基)哌嗪基)乙胺-6-叔丁基氧羰基肼基吡啶-3-甲酸(HYNIC-MPP2).在室温下以N,N-二(2-羟基乙基)氨基乙酸(Bicine)为共配体制备得到配合物~(99)Tc~m-Bicine/HYNIC-MPP2,其放射化学纯度大于95%,并且在6 h内保持稳定.脂水分配系数和电泳实验结果表明,该放射性标记配合物是水溶性和电中性的.正常小鼠体内生物分布实验结果表明,~(99)Tc~m-Bicine/HYNIC-MPP2有一定的脑摄取(注射后2 min时为0.31%ID/g).脑区域分布及抑制实验显示,该配合物在5-HT_(1A)受体含量丰富的海马组织有较高摄取(注射后2 min时为1.00%ID/g),而在受体含量低的小脑组织中摄取也低(注射后2 min时为0.63%ID/g).抑制后,海马摄取降低较多(注射后2 min时为0.42%ID/g),而小脑摄取则无明显变化.抑制前后海马/小脑比值分别为1.59和0.89.由此可见该标记配合物与5-HT_(1A)受体具有一定特异性结合,是一种新的潜在5-HT_(1A)受体显像剂.     

^131I-BIB的合成与生物分布

合成1-三正丁基锡-2，5-二（4＇-氨基）苯乙烯基苯（BIB），并采用双氧水标记法对其进行^131I标记，得到标记物^131I-BIB;将^131I-BIB注入ICR小鼠体内，观察其生物分布。标记结果显示，标记物^131I-BIB的标记率〉60％，放化纯度〉90%；ICR小鼠体内分布实验表明，注射后30min时，^131I-BIB在脑中的摄取最高。^131I-BIB作为髓磷脂显像剂有进一步研究的价值。     

99Tcm标记苯托品类多巴胺转运蛋白显像剂的制备和小鼠体内分布

合成了以苯托品（Benztropine)为前体的含巯基的单齿化合物,其光谱数据和结构相符。使用配体交换法与3－硫杂－1,5－戊二硫醇（SSS）配位合成了^99Tc^m的“3＋1”型混配螯合物a。螯合物a在小鼠脑中有一定的初始摄取和滞留量,在t=5min时,ID＝1.03%／g;对纹状体也有一定的亲和力,纹状体和小脑摄取比值随时间延长而增加,在t=60min时,R（纹状体／小脑）＝1.3。混配螯合物有成为多巴胺转运蛋白显像剂的可能。     

131I-epidepride的制备与SD大鼠体内分布特性研究

采用双氧水标记法和氯胺 -T法进行13 1I -epidepride标记 ,考察标记物的纯度及稳定性 ,并进行SD大鼠体内分布特性研究。实验结果表明 ,双氧水法和氯胺 -T法标记率分别为 97.4 %和 5 2 .9%。标记物的生理盐水溶液室温放置 4h ,放化纯大于 90 %。大鼠静脉注射13 1I -epide pride的生理盐水溶液后 ,纹状体与小脑比值在注射后 32 0min时高达 2 37:1。13 1I -epidepride进入血液后很快被组织摄取 ,其中以肺的早期摄取最高 (2 .11± 1.0 5 ) %ID·g- 1,各脏器的清除均较快 (T1/2 <4h) ,甲状腺的摄取率随时间的延长而增加。     

Radioiodine-Labeling of Chlorpyrifos and Its Biodistribution in Mice

To investigate the preparation of radioiodinated Chlorpyrifos and its biodistribution in mice, Chlorpyrifos was labeled with¹³¹I using the Iodogen method. Biodistribution studies were carried out in KM mice. At different times after radiopharmaceutical i.v. administration (185 kBq¹³¹I-Chlorpyrifos/mouse, n=5), the animals were sacrificed. Blood samples and the tissues of interested were collected, weighted and counted. The percentage of injected does per gram (%ID/g) was calculated for each sample. The labeling yield of ¹³¹I-Chlorpyrifos was 93.5%, The radiochemical purity (RCP) was 96.9%. Biodistribution in mice demonstrated that¹³¹I-Chlorpyrifos was extensive, and the uptakes mainly occur in lung, stomach, small-intestine, colon, musle, and submaxillay gland, as indicated by their amount of 37.12%ID/g, 6.18%ID/g, 8.12%ID/g, 8.15%ID/g, 7.04%ID/g, and 7.02%ID/g at 10 min, respectively. And it was metabolized in liver and kidney, as indicated by their uptake of 4.34%ID/g and 8.50%ID/g at 5 min, and 0.22%ID/g and 0.69%ID/g at 4 h, respectively. In addition,¹³¹I-Chlorpyrifos was cleared out from blood quickly, and the uptake of¹³¹I-Chlorpyrifos in blood was 37.27%ID/g at 5 min, and decreased to 1.35%ID/g at 4 h post injection. In conclusion, ¹³¹I-Chlorpyrifos was stable in vitro and it was absorbed in lung and digestive tract, and it was metabolized mainly in liver and kidney, worthy of further investigation to trace the compound in vivo and in vitro.     

糖基化生长抑素90Y标记及体内外生物学评价

以天然生长抑素(Somatostatin,SMS)、葡聚糖-70(Dextran70,Dx70)及双功能螯合剂2-甲基-6-对氨基苯基二乙三胺五乙酸(1B4M-DTPA)为原料,合成糖基化生长抑素SMS-Dx70-DTPA并进行90Y标记;以125I-奥曲肽(125I-Tyr3-Octreotide)为放射配基,进行受体竞争结合实验,测定SMS-Dx70-DTPA的IC50值;并用90Y-DTPA-Dx70-SMS进行正常大鼠体内分布和血浆清除实验.结果表明:配体化合物SMS-Dx70-DTPA保持了对生长抑素2型受体的高亲和力,其IC50值与SMS相近;90Y-DTPA-Dx70-SMS在正常大鼠体内血浆半衰期为6.39h,主要浓聚于肝、脾并经肾排泄,与葡聚糖的代谢途径基本一致,肾上腺、胰腺具有较高的放射性摄取,且24h内基本保持不变,90Y-DTPA-Dx70-SMS对生长抑素受体阳性组织具有靶向性,有望成为一种新型生长抑素受体阳性肿瘤治疗剂.     

碘标记毒死蜱及其在小鼠体内的生物分布

为探讨¹³¹I标记毒死蜱（Chlorpyrifos, CPF）在小鼠体内的分布特点,采用Iodogen法对CPF进行¹³¹I标记,KM小鼠尾静脉注射¹³¹I-CPF（185 kBq/只,n=5）,分别于注射后5、10、30、60、120、240、1440 min取各脏器,计算每克组织摄取注射剂量的百分率（%ID/g）。结果显示,¹³¹I-CPF标记率达93.5%,放化纯度为96.9%,¹³¹I-CPF在小鼠体内广泛分布,主要经肺、胃、小肠、大肠、肌肉和颌下腺吸收,其放射性摄取率在注药后 10 min 时达高峰,分别为37.12%ID/g、6.18%ID/g、8.12%ID/g、8.15%ID/g、7.04%ID/g和7.02%ID/g;经肝和肾进行代谢,其放射性摄取率在5 min时分别为4.34%ID/g和8.50%ID/g, 4 h为0.22%ID/g和 0.69%ID/g。血液中放射性清除较快,放射性摄取率在注入后5 min时为37.27%ID/g,4 h为1.35%ID/g。碘标记CPF体外稳定,体内主要经肺和消化道吸收,肝、肾代谢,可用于进一步的微量示踪研究。     

Pharmacological studies of dopamine transporter imaging agent 125／131I－β－CIT

To prepare ^125/131I-β-CIT(2β-carbomethoxy-3β-(4-iodophenyl)tropane) as an imaging agent for dopamine transporter (DAT),the labeling method from tributylstannyl precursor with peracetic acid has been reported in this article.The radiochemical purity(RCP) of the labeled compound was over 95% determined by HPLC and TLC.The stability,partition coefficients were also determined.The pharmacological studies of the imaging agent were performed in rats,mice,rabbits and normal monkey.The ligand showed preferable uptake in rats,mice,rabbits and normal monkey.The ligand showed preferable uptake in brain (1.9%ID/organ in rats and 4.5%ID/organ in mice at 5min).The ratios of striatum/cerebellum,hippocampus/cerebellum and cortex/cerebellum were 29.8,3.97and 4.75 at 6h in rats,and 8.52,2.99 and 3.06 at 6h in mice,respectively.In monkey brain imaging the ratios of striatum/frontal cortex(ST/FC)and striatum/occipital cortex(ST/OC) were 5.14 and 5.97 at 4h.respectively,All of above showed the high affinity of the ligand to DAT,The compound was primarily metabolized in liver because the hepatic uptake was much higher than other organs(75.4%ID/organ at 18h).The half-life of blood elimination was 5min.The dose received by mice was 2500 times as high as that received by human in the test of undue toxicity,which evaluated the safety of the agent.All the results suggest that β-CIT can be used as a potential DAT imaging agent.     

18F标记哒嗪酮类似物的制备及其在小鼠体内的生物分布

设计并合成了一种18F标记哒嗪酮类似物：2-特丁基-4-氯-5-(2 氟[18F]乙氧基)-2H-3-哒嗪酮（18F-FP2）,通过生物分布实验评价了其用于心肌灌注显像的可行性。18F-FP2的总制备时间为70～90 min,校正后的放化产率为53.0%±5.2%,放化纯度>98%;18F-FP2为脂溶性化合物,在水溶液中可稳定放置3 h以上。生物分布实验结果显示,18F-FP2在肝、肺中初期摄取高,注射后2 min分别为（14.53±2.36）%ID/g和（33.69±10.79）%ID/g,但清除很快,注射后15 min,其肝、肺的清除率已分别达57.7%和86.2%。18F-FP2的心肌摄取较低,最高摄取值为（4.09±0.53）%ID/g（注射后2 min）。这可能因标记侧链上未带苯环造成的,说明哒嗪酮侧链的芳环结构对心肌的摄取与滞留有较大影响。     

纤维蛋白显像剂131I-YSSCREKA肽的制备及对早期血栓定位的研究

合成了一种可特异性结合纤维蛋白-纤维连接蛋白的早期血栓显像剂¹³¹I-YSSCREKA肽（酪氨酸-（D）丝氨酸-（D）丝氨酸-半胱氨酸-精氨酸-谷氨酸-赖氨酸-丙氨酸），对其标记、SPECT显像及初步生物学性能进行研究。结果表明：YSSCREKA八肽在室温下通过氯胺-T法反应5 min的标记率为(77.2±1.1)%（n=3），放射化学纯度为(90.0±3.1)%（n=3），体外稳定性较好。新西兰家兔SPECT显像显示在¹³¹I-YSSCREKA肽注射后20 h血栓能较清晰地显像，血栓/血放射性比值为1.36。SD大鼠生物分布实验显示：20 h ¹³¹I-YSSCREKA肽在血栓中的摄取率为(0.19±0.06)ID%/g（n=5），血栓/肌肉及血栓/血放射性比值分别为3.80和1.90。¹³¹I-YSSCREKA肽有可能作为早期血栓的显像剂，但其在血栓中的摄取率有待于进一步提高。     

Radio-ligand receptor binding assay in vitro and animal biodistribution in vivo of 99Tcm-N-ethyl-N2S2-memantine as a potential NMDA receptor imaging agent

The pharmacologic characteristics of 99Tcm-N-ethyl-N2S2-memantine,an NMDA receptor imaging agent,was investigated.It was prepared by a one-step reaction from N-ethyl-N2S2-memantine.The affinity and specificity were determined by radio-ligand receptor binding assay(RRA).Biodistribution in vivo in mice was performed.The results showed that 99Tcm-N-ethyl-N2S2-memantine bound to a single site on NMDA receptor with a Kd of 584.32 nmol/L and a Bmax of 267.05 nmol/mg.A competitive analysis showed that such specific binding could be inhibited by specific inhibitors of NMDA receptor,such as ketamine and(+)-MK-801.The biodistribution exhibited rapid uptake and favorable retention in mice brains.The major radioactivity was metabolized by the hepatic system.A two-compartment model of C=4.49e-0.083t+1.42e-0.0016t was established,and the half life was 8.35 min in blood.In conclusion,the new radio-ligand 99Tcm-N-ethyl-N2S2-Memantine has a moderate affinity and specific binding to NMDA receptor,and can easily cross the blood-brain barrier(BBB).Therefore,it may be a potential NMDA receptor imaging agent.