Tissue distribution and excretion of intravenously administered titanium dioxide nanoparticles

As the biosafety of nanotechnology becomes a growing concern, the in vivo nanotoxicity of nanoparticles (NPs) has been drawn an increasing attention. Titanium dioxide nanoparticles (TiO2-NPs) have been developed for versatile use, but the pharmacokinetics of intravenously administered TiO2-NPs have not been investigated extensively. In the present study, the rutile-type TiO2-NPs with a size about 20 nm were labeled with CF680 and 125I. The labeled TiO2-NPs were injected in mice or rats with the concentration of 1 mg/ml and the dose of 10 mg/kg body weight and their tissue distribution and excretion were investigated by using ex vivo fluorescent imaging, γ-counter and TEM. The results indicated that the TiO2-NPs mainly accumulated in liver and spleen and could be retained for over 30 days in these tissues due to the phagocytosis by macrophages. The excretion assay found that the excretory rate of TiO2-NPs through urine was higher than that of feces, indicating that renal excretion was the main excretion pathway of TiO2-NPs. Overall results of the present study provided important information on distribution and excretion of TiO2-NPs in vivo, which would greatly promote the pharmacokinetics and in vivo nanotoxicity research of TiO2-NPs.

► This study reported the pharmacokinetics including tissue distribution and excretion of TiO2-NPs.
► The results indicated the TiO2-NPs accumulated mainly and retained for over 30 days in liver and spleen.
► The excretion assay found that renal excretion was the main excretion pathway of TiO2-NPs.