肝受体显像剂99Tcm-HYNIC-NGA的制备与初步评价

Preparation and Preliminary Evaluate of 99Tcm-HYNIC-NGA Complexes for Hepatic Asialoglycoprotein Receptor Imaging

  • 摘要: 在NGA分子上引入双功能连接剂HYNIC制备了HYNIC-NGA,选用HEDTA及Bicine两种共配体对其进行了99Tcm的标记,考察了标记物在正常小鼠体内的生物分布,并用GSA作为抑制剂(注射剂量10 mg/kg)对99Tcm-HEDTA/HYNIC-NGA进行了抑制实验。结果显示,99Tcm-bicine/HYNIC-NGA及99Tcm-HEDTA/HYNIC-NGA的标记率均大于80%,标记产物经HiTrap脱盐柱进行纯化后,放化纯度均大于95%;生物分布结果显示,99Tcm-bicine/HYNIC-NGA及99Tcm-HEDTA/HYNIC-NGA在注射后5、30、120 min时在肝脏中的摄取分别为56.58±6.57、38.06±3.35、23.17±4.96%ID/g及86.57±5.68、74.63±8.74、45.11±4.21%ID/g。两种配合物均表现了较高的初始肝脏摄取及较好的滞留。用抑制剂后,99Tcm-HEDTA/HYNIC-NGA在注射后5 min时肝脏的摄取明显降低,显示了其与去唾液酸糖蛋白(ASGP)受体的特异性结合。以上结果提示,制得的两种新配合物99Tcm-bicine/HYNIC-NGA及99Tcm-HEDTA/HYNIC-NGA中,99Tcm-HEDTA/HYNIC-NGA具有更好的生物性能,有望发展成为新的ASGP受体显像剂用于肝脏功能的评估。

     

    Abstract: Quantitative imaging of asialoglycoprotein (ASGP) receptors could estimate the function of the liver. HYNIC-NGA was prepared via introduce bifunctional coupling agent hydrazinonicotinamide to NGA and radiolabeled with 99Tcm by using N,N-bis(2-hydroxyethyl)glycine (bicine) and hydroxyethylethylenediaminetriacetic acid (HEDTA) as coligands, respectively. The labeling yield of 99Tcm-bicine/HYNIC-NGA and 99Tcm-HEDTA/HYNIC-NGA was above 80% under the optimized labeling conditions. After purified with HiTrap desalting column, the radiochemical purity of both 99Tcm-complexes were >95%. The biodistribution of 99Tcm-bicine/HYNIC-NGA and 99Tcm-HEDTA/HYNIC-NGA were investigated in normal mice. The blocking experiment of 99Tcm-HEDTA/HYNIC-NGA was performed in normal mice by using GSA (10 mg/kg) as blocking agent. The results of biodistribution showed that the liver uptakes of 99Tcm-HEDTA/HYNIC-NGA were 86.57±5.68%, 74.63±8.74 and 45.11±4.21%ID/g at 5, 30 and 120 min after injection, respectively. While for 99Tcm-bicine/HYNIC-NGA, its liver uptakes were 56.58±6.57, 38.06±3.35 and 23.17±4.96%ID/g, respectively. Both of these tracers showed good initial liver uptake with good retention. The liver uptake of 99Tcm-HEDTA/HYNIC-NGA decreased obviously after blocked by preinjecting free GSA as blocking agent at 5 min after injection, which indicated that the specific could bind to ASGP receptor. Compared with 99Tcm-bicine/HYNIC-NGA, 99Tcm-HEDTA/HYNIC-NGA had higher liver uptake and better retention, and it could be developed as a novel hepatocyte-targeting agent to evaluate hepatic function and clinical use in the future.

     

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