Abstract
18FMISO has played an important role as a hypoxic tracer, presenting with a high specific accumulation in hypoxic cells. 18F is a position emitting nuclide and generally produced from a cyclotron. 18F l led radiopharmaceuticals associated with expensive PET scan, would be restricted in clinical use for patients.[99mTc(CO)3(H2O)3]+ was recently developed as an effective 99mTc labeling precursor, featured with high stability, highly labeling efficiency, and readily coordinating with bidentate or tridentate ligands with N, O and S donors. In this study, it has been attempted to label 99mTc in misonidazole (MISO), a hypoxic agent, using [99mTc(CO)3(H2O)3]+ as the precursor. Radiochemical characterization for the novel 99mTc labeled MISO complex was conducted via high performance liquid chromatography (HPLC)、 thin layer chromatography (TLC),and electrophoresis. Cell uptake test has been performed with tumor cells under aerobic and hypoxic conditions in order to assess the efficacy of 99mTcCO3 □ MISO as a hypoxic agent.In HPLC, [99mTc(CO)3(H2O)3]+ is located at retention time = 4 min. In TLC, the 99mTc species is located at Rf = 0.3. In electrophoresis, it is prone to be positive. In cell uptake test, [99mTc(CO)3(H2O)3]+ presents higher uptake in tumor cells under aerobic condition than under hypoxic condition. For 99mTc(CO)3MISO species by labeling [99mTc(CO)3(H2O)3]+ in MISO, the results of radiochemical characterization are as follows. In HPLC, the 99mTc labeled MISO is located at retention time = 10 min. In TLC the 99mTc-complex species is located at Rf = 0.7. In electrophoresis, it presents to be neutral. In cell uptake test, 99mTc(CO)3MISO displays higher uptake under hypoxic condition than under aerobic condition. In conclusion, this work has demonstrated the labeling of MISO with fac-99mTc(CO)3 for the first time. The novel 99mTc(CO)3MISO species exhibits the potential as a hypoxia tracer. It is worthy to evaluate furthermore the 99mTc labeled MISO complex as a hypoxia imaging agent for clinical use.