PRELIMINARY EVALUATION OF AN ANTHRAQUINONE CONJUGATED DOTA DERIVATIVE AS SPECT AGENT

Objective : An anthraquinone derivative, DO3A-Act-AQ having DO3A (1, 4, 7, 10-tetraazacyclododecane-1, 4, 7-trisacetic acid) scaffold is radio labeled with 99m Tc radioisotope and evaluated as a SPECT imaging agent for tumor. Methods : Preliminary in-vivo evaluation of 99m Tc-DO3A-Act-AQ radioconjugate including blood kinetics, biodistribution and gamma scintigraphic imaging is performed on BMG-1 tumor xenografted mice after successful optimization of the radiolabeling condition. Results : The radiotracer, 99m Tc-DO3A-Act-AQ was produced in high radiochemical yield of>96% and specific activity of 3.62 MBq/nmol at pH 7.5 and 150 µg stannous chloride. Radioconjugate displayed excellent in-vitro and in-vivo stability with only ~2% transchelation of radiometal at 24 h p. i and rapid blood clearance from the system with t 1/2 (F) = 38.04±0.35 min and t 1/2 (S) = 5 h 30 min±0.67. Significant tumor-to-muscle ratio of>7 at 2 h p. i. in biodistribution and SPECT imaging studies in BMG-1 tumor xenografted mice suggested the tumor specificity of the radioconjugate. Conclusion : Stable radiocomplex formation of 99m Tc-DO3A-Act-AQ and its significant tumor specificity demonstrated its future application as a promising SPECT radioligand for tumor imaging.