Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences (INMAS), Brig. SK Mazumdar Road, Near Timarpur, Delhi, 110054, India.
Int J Infect Dis. 2013 Apr;17(4):e263-70. doi: 10.1016/j.ijid.2012.10.011. Epub 2012 Dec 6.
In this study we sought to assess the efficacy of a technetium-99m (Tc-99m)-labeled third-generation cephalosporin as an infection imaging agent in the accurate detection of the sites of bacterial infection in vivo.
Ceftriaxone (CRO) was formulated into a ready-to-use single-vial cold kit with a shelf-life of over 6 months and was successfully labeled with technetium. The radiolabeled drug, Tc-99m-CRO, was subjected to the following preclinical evaluations: radiochemical purity, in vitro and in vivo stability, bacterial binding assay, and pharmacokinetic studies in animals and in human patients.
The kit formulation exhibited excellent radiolabeling efficiency (∼99%) and high in vitro and in vivo stability. The radiolabeled drug exhibited slow blood clearance (12% at 4 h), and the high protein binding and excretion pattern of the labeled formulation mimics the reported pharmacokinetic profile of the drug alone. In the animal model, scintigraphy scans showed higher uptake of the radiopharmaceutical in infectious lesions, even at 1 h post-administration, in comparison to inflammatory lesions. The clinical evaluation of Tc-99m-labeled CRO showed a diagnostic accuracy of 83.3%, and a sensitivity and specificity of 85.2% and 77.8%, respectively.
This kit formulation has the potential for imaging bacterial infections with much higher sensitivity and specificity as compared to other Tc-99m-labeled antibiotics available as convenient ready-to-use kits in routine clinical practice.
本研究旨在评估锝-99m（Tc-99m）标记的第三代头孢菌素作为感染成像剂，在体内准确检测细菌感染部位的疗效。
头孢曲松（CRO）被制成即用型单瓶冷制剂，保质期超过 6 个月，并成功标记了锝。放射性标记药物 Tc-99m-CRO 进行了以下临床前评估：放射化学纯度、体外和体内稳定性、细菌结合测定以及动物和人类患者的药代动力学研究。
试剂盒制剂表现出优异的放射标记效率（约 99%）和高体外和体内稳定性。放射性标记药物表现出缓慢的血液清除率（4 小时时为 12%），标记制剂的高蛋白结合和排泄模式模拟了单独药物的报道药代动力学特征。在动物模型中，与炎症病变相比，放射性药物在感染病变中的摄取更高，甚至在给药后 1 小时。Tc-99m 标记 CRO 的临床评估显示诊断准确性为 83.3%，灵敏度和特异性分别为 85.2%和 77.8%。
与常规临床实践中作为即用型方便试剂盒提供的其他 Tc-99m 标记抗生素相比，这种试剂盒制剂具有更高的灵敏度和特异性，用于成像细菌感染的潜力。
