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Basic toxicokinetics

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basic toxicokinetics in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Test according to state-of-the-art operating procedures for testing of metal bioelution.

Data source

Reference Type:
study report
Report date:

Materials and methods

Objective of study:
bioaccessibility (or bioavailability)
Principles of method if other than guideline:
The release/dissolution of zinc from zinc oxide in artificial lysosomal fluid was measured. The resulting value is termed bio-accessibility, and is defined as the fraction of a substance that is soluble under physiological conditions and therefore potentially available for absorption into systemic circulation. The simulated lysosomal fluid represents an exposure-relevant exposure route (inhalation exposure.). The compound was introduced as powder in a test item / solution ratio of 2g/L during 24, 48 and 72 hours.

GLP compliance:

Test material

Constituent 1
Chemical structure
Reference substance name:
Zinc oxide
EC Number:
EC Name:
Zinc oxide
Cas Number:
Molecular formula:
Test material form:
other: nanomaterial (coated)
Details on test material:
- Name of test material (as cited in study report): Z-COTE® HP1
- Physical state: white powder, solid, odourless
- non-flammable
- melting point: approx. 1970 °C
- density: 5.47g/cm3
- solubility in water: practically insoluble: 1.6 mg/L (21 °C); soluble in diluted mineral acids , solubility in M4 medium: 2.4 mg/l
- particle size <200 nm
- particle surface area of 12-24 m²/g
- Lot/batch No: NPL Ref#: ZB250#65
- Expiration date of the lot/batch: at least until June 2014

Test animals

Details on test animals or test system and environmental conditions:
not applicable

Administration / exposure

Details on exposure:
not applicable

Results and discussion

Preliminary studies:
not applicable
Main ADME results
other: bioaccessibility
artificial lysosomal fluid (ALF) - as %Zn released of total Zn content: >90

Toxicokinetic / pharmacokinetic studies

Details on absorption:
not applicable
Details on distribution in tissues:
not applicable
Details on excretion:
not applicable

Bioaccessibility (or Bioavailability)

Bioaccessibility (or Bioavailability) testing results:
lysosomal bioaccessibility - as %Zn released of total Zn content: >90%

Any other information on results incl. tables

pH 4.5 artificial lysosomal fluid:

 test item  %Zn released of total Zn content   
 blank <0.01     
 Z-COTE HP1  >90  
 Z-COTE  >90   
 microscaled  >90 

Applicant's summary and conclusion

Interpretation of results (migrated information): other: High bioaccessibility of Zn2+ from ZnO. The dissolution in artificial lysosomal fluid is used to estimate bioavailability after inhalation exposure
Bio-elution test according to state-of-the-art procedures, useful for determining dissolution capacity of Zn in artificial lysosomal fluid.
Executive summary:

During this study on ZnO in different forms (nano- (coated, non-coated) and microscaled ZnO) at a loading of 2 g/L in artificial lysosomal fluid (pH 4.5), it was shown that high amounts of zinc were measured. For nano ZnO, coated a zinc release of >90% was found.