Biodistribution and Human Absorbed Dose Evaluation of an Organic-Inorganic Nanocomposite Containing 198Au (198Au/PG4D)

An organic-inorganic nanocomposite 198Au/PD4G was synthesize 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 198Au was produced by irradiation of natural gold (197Au) in a medium flux reactor with 3×1011n/cm2.s flux of thermal neutron. Gamma spectroscopy exhibited only one characteristic peak of 198Au at 411 KeV as well as a radiochemical purity of more than 82% (using ITLC) was obtained for final formulation of 198Au/PG4D (37MBq). A single intratumoral injection of 88μCi of 198Au/PG4D resulted statistically significant 65% reduction in 4T1 tumor volume after 20 days. Biodistribution investigations showed that the tumor had a maximum 198Au/PG4D uptake 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.