Pharmacokinetics, tissue distribution, and excretion of zinc oxide nanoparticles.
BACKGROUND
This study explored the pharmacokinetics, tissue distribution, and excretion profile of zinc oxide (ZnO) nanoparticles with respect to their particle size in rats.


METHODS
Two ZnO nanoparticles of different size (20 nm and 70 nm) were orally administered to male and female rats, respectively. The area under the plasma concentration-time curve, tissue distribution, excretion, and the fate of the nanoparticles in organs were analyzed.


RESULTS
The plasma zinc concentration of both sizes of ZnO nanoparticles increased during the 24 hours after administration in a dose-dependent manner. They were mainly distributed to organs such as the liver, lung, and kidney within 72 hours without any significant difference being found according to particle size or rat gender. Elimination kinetics showed that a small amount of ZnO nanoparticles was excreted via the urine, while most of nanoparticles were excreted via the feces. Transmission electron microscopy and x-ray absorption spectroscopy studies in the tissues showed no noticeable ZnO nanoparticles, while new Zn-S bonds were observed in tissues.


CONCLUSIONS
ZnO nanoparticles of different size were not easily absorbed into the bloodstream via the gastrointestinal tract after a single oral dose. The liver, lung, and kidney could be possible target organs for accumulation and toxicity of ZnO nanoparticles was independent of particle size or gender. ZnO nanoparticles appear to be absorbed in the organs in an ionic form rather than in a particulate form due to newly formed Zn-S bonds. The nanoparticles were mainly excreted via the feces, and smaller particles were cleared more rapidly than the larger ones. ZnO nanoparticles at a concentration below 300 mg/kg were distributed in tissues and excreted within 24 hours. These findings provide crucial information on possible acute and chronic toxicity of ZnO nanoparticles in potential target organs.
Department of Food Science and Technology, Seoul Women's University, Seoul, Republic of Korea.
Miri
M
Baek
Hae-Eun
HE
Chung
Jin
J
Yu
Jung-A
JA
Lee
Tae-Hyun
TH
Kim
Jae-Min
JM
Oh
Won-Jae
WJ
Lee
Seung-Min
SM
Paek
Jong Kwon
JK
Lee
Jayoung
J
Jeong
Jin-Ho
JH
Choy
Soo-Jin
SJ
Choi
D000042:Absorption; D000284:Administration, Oral; D000818:Animals; D005243:Feces / Q000737:chemistry; D005260:Female; D008297:Male; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D015034:Zinc Oxide / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics*
D015034:Zinc Oxide