Biodistribution and human absorbed dose evaluation of an organic-inorganic nanocomposite containing 198Au (198Au/PG4D)

An organic-inorganic nanocomposite 198 Au/PG4D was synthesized using polyamidoamine G4 dendrimer and applied as an anticancer agent against 4T1 carcinoma tumor as well as for biodistribution and human absorbed dose investigation. Radionuclide 198 Au was produced by irradiation of natural gold ( 197 Au) in a medium flux reactor with 3 × 10 11 n/cm 2 .s flux of thermal neutron. Gamma spectroscopy exhibited only one characteristic peak of 198 Au at 411 KeV as well as a radiochemical purity of more than 82% (using ITLC) was obtained for final formulation of 198 Au/PG4D (37MBq). A single intratumor injection of 3 . 26MBq (88 μ Ci) of 198 Au/PG4D resulted in statistically significant 65% growth inhibition in 4T1 tumor volume after 20 days. Biodistribution investigations showed that the tumor had a maximum accommodated activity owing to 198 Au/PG4D of 81.27% and 79.37% at 4 and 24 h post injection. The human’s absorbed dose, furthermore, was extrapolated via the biokinetics data of mice so that the doses absorbed in the critical organs such as the bone, lung, spleen, kidney, and liver are 0.0669, 1.1, 0.221, 0.0983 and 0.282 mGy/MBq, respectively.