Tissue distribution and clearance of intravenously administered titanium dioxide (TiO2) nanoparticles.

The organ-tissue distribution and clearance of Degussa P25 TiO2 nanoparticlesweredeterminedafterintravenousadministrationto rats(0.95mg/kgbodyweight)usinganinductivelycoupledplasma sector field mass spectrometer. The detection limits of Ti analysis, 0.54and1.4ng/mLforbloodandurineand0.35–2.0ng/gtissuefor severalorgantissues, enableddeterminationoftissuedistribution and clearance for organs in which Ti content could not be previously determined due to low concentrations. Blood concentrationsofTiO2were420and19ng/mLat5and15minafter administration, which were equivalent of only 2.8% and 0.13% of the administration dose, respectively. At 6 h, 94%, 2.0%, 0.17%, 0.023%,0.014%and0.026%ofadministeredTiO2wasfoundinthe liver, spleen,lung,kidney, heart andblood,respectively. Liverand spleen TiO2 burden was significantly higher in the administration than control group (p < 0.01) and did not decrease up to 30 days after administration, while TiO2 burden in the lung, kidney, heart andblooddecreasedovertime.Atwo-stepdecaymodelwasmore suitable than a one-step decay model for the decay curves of pulmonary TiO2 burden but did not improve fitting to the decay curves of kidney TiO2 burden. No translocation to the brain was confirmed at a lower detection limit than was applied in previous studies. Ti content in faeces and urine in the TiO2 administration group did not differ from that in the control group.