In this study, ethylene diamine tetraacetic acid-deoxyglucose (EDTADG) ligand was successfully synthesized and then radiolabeled with 99mTc directly to produce 99mTc-EDTADG with high radiochemical purity. 99mTc-EDTADG showed good in vitro stability. The partition coefficient and electrophoresis results showed it was hydrophilic and negatively charged. The biodistribution study in mice bearing S180 tumor showed that 99mTc-EDTADG had high accumulation in tumor tissue with high tumor-to-muscle and tumor-to-blood ratios. Single photon emission computed tomography imaging clearly visualized the tumor, suggesting it could be considered as a potential agent for tumor imaging.

The deoxyglucose dithiocarbamate (DGDTC) was successfully labeled with the 99mTc(CO)3 core to provide the corresponding 99mTc(CO)3–DGDTC complex in good yields. The radiochemical purity of the 99mTc(CO)3–DGDTC complex was over 90%, as measured by high performance liquid chromatography (HPLC). The complex possessed good stability in saline at room temperature and in mouse plasma at 37 °C. Its partition coefficient result indicated that it was a hydrophilic complex. The electrophoresis results showed the complex was neutral. The biodistribution of 99mTc(CO)3–DGDTC in mice bearing S 180 tumor showed that the complex clearly accumulated in tumor, exhibiting high tumor/blood and tumor/muscle ratios and good tumor retention. Single photon emission computed tomography (SPECT) image studies showed there was a visible uptake in tumor sites, suggesting 99mTc(CO)3–DGDTC could be considered as a potential tumor imaging agent.DGDTC was successfully radiolabeled with [99mTc(CO)3(H2O)3]+ precursor to obtain 99mTc(CO)3–DGDTC in high yield. The biodistribution and SPECT studies in various tumor animals showed that 99mTc(CO)3–DGDTC exhibited very promising properties for tumor imaging.

The 2-[(3-carboxy-1-oxopropyl)amino]-2-deoxy-d-glucose (CPADG) was synthesized and radiolabeled with 99mTcO4− to obtain the 99mTc–CPADG complex in high yield. It was stable over 6 h in saline at room temperature and in serum at 37 °C. The partition coefficient and electrophoresis results indicated that the complex was hydrophilic and cationic. In vitro cell studies showed there was an increase in the uptake of 99mTc–CPADG as a function of incubation time and 99mTc–CPADG was possibly transported via the glucose transporters. The biodistribution of 99mTc–CPADG in mice bearing S 180 tumor showed that the complex accumulated in the tumor with high uptake and good retention. The tumor/blood and tumor/muscle ratios increased with time and reached 1.91 and 5.05 at 4 h post-injection. Single photon emission computed tomography (SPECT) image studies showed there was an obvious accumulation in tumor sites, suggesting 99mTc–CPADG would be a promising candidate for tumor imaging.CPADG was successfully synthesized and radiolabeled with 99mTc to obtain 99mTc–CPADG in high yield. The biodistribution and SPECT studies in various tumor animals showed that 99mTc–CPADG a very promising candidate for tumor imaging.

Achieving a 99mTc-labeled fluoroquinolone derivative as a single photon emission computed tomography (SPECT) tracer is considered to be of great interest. The norfloxacin dithiocarbamate (NFXDTC) was synthesized and radiolabeled with a [99mTcN]2+ intermediate to form the 99mTcN-NFXDTC complex in high yield. The radiochemical purity of 99mTcN-NFXDTC was over 90%, as measured by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC), without any notable decomposition at room temperature over a period of 6 h. The partition coefficient and electrophoresis results indicated that 99mTcN-NFXDTC was lipophilic and neutral. The bacterial binding assay studies showed tht 99mTcN-NFXDTC had a good binding affinity. Biodistribution results in bacterial infected mice showed that 99mTcN-NFXDTC had a higher uptake at the sites of infection and better abscess/blood and abscess/muscle ratios than those of 99mTc-ciprofloxacin and 99mTcN-CPFXDTC (CPFXDTC = ciprofloxacin dithiocarbamate). The biodistribution results of 99mTcN-NFXDTC in bacterially infected mice and in mice with turpentine-induced abscesses indicated that 99mTcN-NFXDTC was suited to be a bacteria-specific infection imaging agent. Single photon emission computed tomography (SPECT) image studies showed there was a visible accumulation in infection sites, suggesting that it would be a promising candidate for bacterial infection imaging.

The ciprofloxacin dithiocarbamate (CPFXDTC) was radiolabeled with [99mTc(CO)3(H2O)3]+ intermediate to form the 99mTc(CO)3–CPFXDTC complex in high yield. The 99mTc(CO)3–CPFXDTC complex was characterized by HPLC and its stability in serum was studied. Its partition coefficient indicated that it was a lipophilic complex. The bacterial binding efficiency of 99mTc(CO)3–CPFXDTC was almost the same as that of 99mTcN–CPFXDTC, and was higher than that of 99mTc–ciprofloxacin. Biodistribution results in induced infection mice showed 99mTc(CO)3–CPFXDTC had higher uptake at the sites of infection and better abscess/blood and abscess/muscle ratios than those of 99mTc–ciprofloxacin and 99mTcN–CPFXDTC. Single photon emission computed tomography (SPECT) static imaging study in infected rabbits demonstrated the uptake in the left thigh infection lesion was observable, while no accumulation in the right thigh muscle was found. These results suggested 99mTc(CO)3–CPFXDTC would be a promising candidate for further evaluation as infection imaging agent.The ciprofloxacin dithiocarbamate (CPFXDTC) was radiolabeled with [99mTc(CO)3(H2O)3]+ intermediate to form the 99mTc(CO)3–CPFXDTC complex in high yield. The biodistribution and SPECT imaging studies reveal its good biological features as an infection imaging agent.

The deoxyglucose dithiocarbamate (DGDTC) was synthesized and radiolabelled with [99mTcN]2+ intermediate to form the 99mTcN–DGDTC complex. The radiochemical purity of the 99mTcN–DGDTC complex was over 90%, as measured by TLC and by HPLC, without any notable decomposition at room temperature over a period of 6 h. The partition coefficient and electrophoresis results indicated that this complex was hydrophilic and neutral. The biodistribution of 99mTcN–DGDTC in mice bearing S 180 tumor showed that the complex accumulated in the tumor with high uptake and good retention. The tumor/blood and tumor/muscle ratios increased with time and reached 2.32 and 1.68 at 4 h post-injection, suggesting it would be a promising candidate for tumor imaging.The deoxyglucose dithiocarbamate (DGDTC) was synthesized and radiolabelled with [99mTcN]2+ intermediate to form the 99mTcN–DGDTC complex in high yield (>90%). The biodistribution results suggested 99mTcN–DGDTC would be a promising candidate for tumor imaging.

In the present study, a novel 99mTc nitrido dithiocarbamate complex containing ether group, the bis(2-ethoxyethyl dithiocarbamato) nitrido 99mTc complex 99mTcN(EOEDTC)2 has been synthesized by the reduction of 99mTcO4− into [99mTcN]2+ with stannous chloride in the presence of succinic dihydrazide and propylenediamine tetraacetic acid, followed by the addition of the corresponding dithiocarbamate ligand. The radiochemical purity of the complex was over 90% as measured by thin layer chromatography (TLC). In vitro studies showed that the complex possessed good stability. Its partition coefficient indicated that it was lipophilic complex. The electrophoresis results showed the complex was neutral. Biodistribution in mice showed that the complex accumulated in the heart and brain with high initial uptake, suggesting the complex may lead to a further development of the radiopharmaceutical as a heart and brain perfusion tracer.

A novel 99mTc nitrido xanthate complex 99mTcN(IPEXT)2 (IPEXT: isopentyl xanthate) has been synthesized by the reduction of 99mTcO4− into [99mTcN]2+ with stannous chloride in the presence of succinic dihydrazide and propylenediamine tetraacetic acid, followed by the addition of the corresponding xanthate ligand. The radiochemical purity of the complex was over 90% as measured by thin layer chromatography (TLC). No decomposition of the complex at room temperature was observed over a period of 6 hours. Its partition coefficient indicated that it was a lipophilic complex. The electrophoresis results showed the complex was neutral. Biodistribution in mice showed that the 99mTcN(IPEXT)2 complex accumulated in the heart with high uptake. The heart uptake (%IDg) was 8.00% at 5-minute post-injection, but the heart/lung, heart/liver and heart/blood ratios were not high, thereby, restricting the use of the complex as a good myocardial imaging agent.

IntroductionAchieving an ideal 99mTc labeled nitroimidazole hypoxia marker is still considered to be of great interest. Metronidazole xanthate (MNXT) ligand was synthesized and radiolabeled with 99mTc-glucoheptonate (GH) to form the 99mTcO-MNXT complex, for the potential use as a novel probe for imaging tumor hypoxia.MethodsFor labeling, 99mTcO-MNXT was prepared by ligand-exchange reaction with 99mTc-GH. The radiochemical purity of the 99mTcO-MNXT complex was measured by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The distribution coefficient and stability of the complex was investigated. The structure of the 99mTcO-MNXT complex was verified by preparation and characterization of the corresponding stable rhenium complex. The cellular uptake of the 99mTcO-MNXT complex was determined in murine sarcoma S180 cell lines under hypoxic and aerobic conditions. The biodistribution and single photon emission computed tomography (SPECT) image studies of the 99mTcO-MNXT complex were performed in mice bearing S 180 tumor.ResultsThe radiochemical purity of the 99mTcO-MNXT complex was over 90%. It had good in vitro stability and its distribution coefficient indicated that it was a hydrophilic complex. When 99mTc and Re complexes were coinjected in HPLC, both radioactivity (for 99mTc complex) and UV detectors (for Re complex) showed nearly identical HPLC profiles, suggesting their structures are similar. The tumor cell experiment and the biodistribution in mice bearing S 180 tumor showed that the 99mTcO-MNXT complex had a good hypoxic selectivity and accumulated in the tumor with high uptake and good retention. Single photon emission computed tomography (SPECT) image studies showed that the tumor detection was observable.Conclusions99mTcO-MNXT is prepared from a kit without the need for purification and shows high tumor uptake, tumor/blood and tumor/muscle ratios, suggesting that it would be a promising candidate for imaging tumor hypoxia.