Preparation, Quality Control and Biodistribution Analysis of ⁶⁴Cu Labeled DKFZ-PSMA-617 and its Clinical Translation Research

Objective: In order to provide a new probe for the PET imaging of the high expression of PSMA related tumors. The production, quality control and bio-distribution of ⁶⁴Cu-PSMA-617 were established. Methods: ⁶⁴Ni (p, n) ⁶⁴Cu nuclear reaction was applied for the production of ⁶⁴Cu. The labeling conditions were optimized to achieve rapid labeling process and high purity of ⁶⁴Cu-PSMA-617 formulation. Radio-thin layer chromatography (Radio-TLC) and Radio-high performance liquid chromatography (Radio-HPLC) were used to detect the purity and stability of ⁶⁴Cu-PSMA-617. Referring to the 2015 Chinese pharmacopoeia standard, the preliminary quality control of ⁶⁴Cu-PSMA-617 was carried out. The bio-distribution of the probe was evaluated by intravenous injection of 1.85 MBq ⁶⁴Cu-PSMA-617 to Balb/c mice. Results: The labeled yield of ⁶⁴Cu-PSMA-617 was over 96%, the radiochemical purity was over 98%, and the tracer remained 24 hours in various buffers. After the injection of the tail vein in mice, bio-distribution studies at 1 hour, 24 hours and 48 hours. ⁶⁴Cu-PSMA-617 showed that the radioactivity was mainly accumulated in the liver/kidney, which accorded with the metabolic behavior. Conclusion: In this study, ⁶⁴Cu was rapidly labeled to formulate ⁶⁴Cu-PSMA-617 tracer. The quality control method was established and validated. ⁶⁴Cu-PSMA-617 exhibits good radio-chemical properties. Bio-distribution studies confirm that it has good biological properties. It lays the foundation for the further clinical translational study in non-invasive PET imaging of prostate cancer.