Multifunctional ^99mTc-5-azacitidine Gold Nanoparticles: Formulation, In Vitro Cytotoxicity, Radiosynthesis, and In Vivo Pharmacokinetic Study

Background: 5-azacitidine is a very potent chemotherapeutic agent that suffers from certain disadvantages. Objective: This study aims to prepare gold nanoparticles as a new nano-formula of 5-azacitidine that can improve its bioavailability and decrease its side effects. Methods: 5-azacytidine-loaded GA-AuNPs were prepared and characterized by UV-Vis spectroscopy, infrared (IR), and electronic transmission microscope (TEM). This new platform was characterized in vitro by measuring its zeta potential, particle size, and drug loading efficacy, and the anti-proliferative effect on the MCF-7 cell line was evaluated. In vivo biodistribution studies of ^99mTc-5-aza solution and ^99mTc-5-aza-gold nano formula were conducted in tumor-bearing mice by different routes of administration (intravenous and intra-tumor). Results: 5-Aza-GA-AuNPs formula was successfully prepared with an optimum particle size of ≈34.66 nm, the zeta potential of -14.4 mV, and high entrapment efficiency. ^99mTc-5-Aza-GA-AuNPs were successfully radiosynthesized with a labeling yield of 95.4%. Biodistribution studies showed high selective accumulation in tumor and low uptake in non-target organs in the case of the 5-Aza-GA-AuNPs formula than the ^99mTc-5-azacitidine solution. Conclusion: ^99mTc-5-Aza-GA-AuNPs improved the selectivity and uptake of 5-azacitidine in cancer. Moreover, ^99mTc-5-Aza-GA-AuNPs could be used as hopeful theranostic radiopharmaceutical preparation for cancer.