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Open Access Research

Comparative absorption, distribution, and excretion of titanium dioxide and zinc oxide nanoparticles after repeated oral administration

Wan-Seob Cho1, Byeong-Cheol Kang2, Jong Kwon Lee3, Jayoung Jeong3, Jeong-Hwan Che2* and Seung Hyeok Seok4*

Author Affiliations

1 Department of Medicinal Biotechnology, College of Natural Resources and Life Science, Dong-A University, Busan, 604-714, Republic of Korea

2 Biomedical Research Institute, Seoul National University Hospital, Seoul, 110-744, Republic of Korea

3 Department of Toxicological Research, National Institute of Food and Drug Safety Evaluation, Korea Food and Drug Administration, Osong, 363-700, Republic of Korea

4 Department of Microbiology and Immunology, and Institute of Endemic Disease, Seoul National University College of Medicine, Seoul, 110-799, Republic of Korea

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Particle and Fibre Toxicology 2013, 10:9  doi:10.1186/1743-8977-10-9

Published: 26 March 2013

Abstract

Background

The in vivo kinetics of nanoparticles is an essential to understand the hazard of nanoparticles. Here, the absorption, distribution, and excretion patterns of titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles following oral administration were evaluated.

Methods

Nanoparticles were orally administered to rats for 13 weeks (7 days/week). Samples of blood, tissues (liver, kidneys, spleen, and brain), urine, and feces were obtained at necropsy. The level of Ti or Zn in each sample was measured using inductively coupled plasma-mass spectrometry.

Results

TiO2 nanoparticles had extremely low absorption, while ZnO nanoparticles had higher absorption and a clear dose-response curve. Tissue distribution data showed that TiO2 nanoparticles were not significantly increased in sampled organs, even in the group receiving the highest dose (1041.5 mg/kg body weight). In contrast, Zn concentrations in the liver and kidney were significantly increased compared with the vehicle control. ZnO nanoparticles in the spleen and brain were minimally increased. Ti concentrations were not significantly increased in the urine, while Zn levels were significantly increased in the urine, again with a clear dose-response curve. Very high concentrations of Ti were detected in the feces, while much less Zn was detected in the feces.

Conclusions

Compared with TiO2 nanoparticles, ZnO nanoparticles demonstrated higher absorption and more extensive organ distribution when administered orally. The higher absorption of ZnO than TiO2 nanoparticles might be due to the higher dissolution rate in acidic gastric fluid, although more thorough studies are needed.

Keywords:
TiO2; ZnO; Oral administration; Absorption; Distribution; Excretion