Preparation, Biodistribution of 99mTc-Azacytidine Complex as a Potential Agent for Radiotherapy

Objectives: This study aimed at exploring the possibility of radiolabeling 5-Azacytidine with technetium-99m (99mTc) as a surrogate for Rhenium- 186/188 in order to explore the possibility of using the radiolabeled complex as a targeted radiotherapeutic agent. Methods: Radiolabeling of 5-Azacytidine with 99mTc via complexation reaction using stannous chloride dihydrate as a reducing agent. The biodistribution of the formed complex was then studied in tumour bearing mice. Results: Successful radiolabeling of 5-Azacytidine with 99mTc was achieved with radiolabeling yield 84.94%. The formed complex showed in vitro stability up to 60 min post labelling. The biodistribution study of the complex showed a Target /Non-target ratio of 2.27 at 2h post injection suggesting good localization of the complex. Conclusion: The radiolabeling of 5-Aza was successfully achieved with 99mTc. The biodistribution study in tumour bearing mice showed good localization of the radiolabeled complex at the tumour site, however further studies are needed for achieving better targeting of the complex.