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Table 4 Measured test substance deposition in the lung, expected deposition calculated by the Multiple Path Particle Dosimetry (MPPD) model, measured (absolute and relative) decrease of lung burden (clearance) after the recovery period

From: Application of short-term inhalation studies to assess the inhalation toxicity of nanomaterials

Test substance Assumed 100% deposition (mg) (Lung burden) Measured test material on study day 5 (μg/lung) Measured deposition (%) Calculated deposition (%) Measured lung burden after recovery period (μg/lung) % Decrease of lung burden after recovery perioda
Coated nano-TiO 2 (T-lite SF™ containing 82% TiO 2 and 10% Al(OH) 3 ) 3.85 459.0 ± 71.3 (TiO2) 49.1 ± 7.6 (Al(OH)3) 12.4%b 19.1% 467.4 ± 43.4 (TiO2) 46.3 ± 5.0 (Al(OH)3) +1%
Micron-scale ZnO 5.508 82.3 ± 12.5 1.5% 10.3% 27.1 ± 1.5 n.a.
Coated nano-ZnO (NM-111) 0.216 33.9 ± 7.0 15.7% 12.4% 25.4 ± 1.3 n.a.
1.008 123.4 ± 28.4 12.2% 13.5% 26.3 ± 1.5 n.a.
4.968 428.2 ± 19.4 8.6% 13.4% 28.4 ± 4.1 n.a.
SiO 2 .naked 18.936 342.3 ± 10.7 1.8% 5.1% 208.2 ± 16.1 −39%
SiO 2 .acrylate 0.216 18.6 ± 6.2 8.6% 7.1% 15.7 ± 6.9 −16%
0.756 37.1 ± 6.9 4.9% 7.9% 30.0 ± 7.7 −19%
3.492 200.0 ± 30.9 5.7% 6.8% 132.1 ± 43.3 −34%
SiO 2 .PEG 0.738 59.2 ± 11.0 8.0% 8.8% 25.7 ± 2.1 −57%
3.60 182.6 ± 27.1 5.1% 8.8% 117.0 ± 45.7 −36%
19.476 834.3 ± 206.3 4.3% 6.5% 370.8 ± 40.5 −56%
SiO 2 .phosphate 1.044 71.3 ± 11.0 6.8% 10.9% 47.8 ± 3.3 −33%
3.60 194.7 ± 11.9 5.4% 6.1% 104.8 ± 21.4 −46%
18.54 499.2 ± 30.9 2.7% 6.2% 303.8 ± 91.1 −39%
SiO 2 .amino 0.756 87.0 ± 14.2 11.5% 10.5% 52.1 ± 9.6 −41%
3.672 295.9 ± 81.7 8.1% 5.3% 154.7 ± 25.7 −48%
18.144 741.6 ± 157.7 4.1% 5.4% 474.2 ± 155.1 - 36%
Nano-BaSO 4 (NM-220) c 19.224 1055.7 5.5% 9.6% 239.7 −77%
Nano-ZrO 2 0.18 18.0 ± 5.6 10.0% 7.3% 6.8 ± 3.6 −62%
0.936 20.3d 117.5 2.2% 12.6% 8.2% 29.3 ± 6.2 −75%
3.456 270.6 ± 28.9 7.8% 6.7% 157.6 ± 19.0 −42%
ZrO 2 .TODA 0.720 83.3 ± 6.4 11.6% 10.9% 41.9 ± 5.4 −50%
3.816 233.2 ± 6.9 6.1% 10.9% 87.3 ± 62.8 −63%
18.792 693.4 ± 121.8 3.7% 7.7% 520.5 ± 82.0 - 25%
ZrO 2 .acrylate 0.684 7e 1.0% 16.0% LOQ  
3.636 70 1.9% 11.1% 49 - 30%
18.18 169 0.9% 7.7% 190 + 12%
Nano-scale CeO 2 0.277 52.0 ± 5.0 18.8% 16.6% 44.2 ± 4.4 −15%
1.069 165.8 ± 18.4 15.5% 14.3% 157.6 ± 18.7 −5%
4.176 417.6 ± 44.3 10.0% 15.4% 470.9 ± 51.2 +13%
Al-doped nano-scale CeO 2 c 3.312 326.8 7.8% 6.8% 304.7 −7%
  1. n.a.: Not applicable: Zn content returned to control levels in all concentration groups. No relative decrease of lung burden was calculated due to high endogenous content of Zn.
  2. LOQ: limit of quantification.
  3. aRecovery period for SiO2.acrylate was 14 days after the final exposure. For all other substances, the recovery period was 21 days.
  4. bTotal amount of TiO2 and Al(OH)3 was assumed as total deposition.
  5. cOnly one rat was examined.
  6. dOnly two samples were examined which differed considerably and hence are presented as individual animal data.
  7. eData for one animal, LOQ in the other two.