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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1997-10-20 to 1997-12-19
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Yttrium zirconium oxide
EC Number:
264-885-7
EC Name:
Yttrium zirconium oxide
Cas Number:
64417-98-7
Molecular formula:
(ZrO2)x (Y2O3)y 0.59 < x < 1.0 and 0 < y < 0.41
IUPAC Name:
Yttria-Stabilised Zirconia
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): zirconium oxide (5.15 wt% yttrium oxide intercrystallised)
- Molecular formula (if other than submission substance): 97ZrO2 3Y2O3 (mole fraction)
- Molecular weight (if other than submission substance): 123.22
- Physical state: white powder
- Stability under test conditions: no data
- Storage condition of test material: stored in cool, dark place
- Further details on test material confidential

Method

Target gene:
histidine locus (Salmonella typhimurium)
tryptophan locus (Escherichia coli)
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9 induced rat liver
Test concentrations with justification for top dose:
Dose-setting test: 5, 10, 50, 500, 1000, and 5000 µg/plate
Final test: 0.156, 0.313, 0.625, 1.25, 2.5 and 5 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: distilled water
- Justification for choice of solvent/vehicle: no data
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
distilled water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide (AF-2)
Remarks:
For strains: TA 98, TA 100 and WP2 uvrA without S9 mix
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
distilled water
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
For strains: TA 1535 without S9 mix
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
distilled water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: 2-methoxy-6-Chloro-9-[3-(2-chloroethyl)-aminopropylamino] acridine ¿ 2HCl(ICR-191)
Remarks:
For strains: TA 1537 without S9 mix
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
distilled water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (2AA)
Remarks:
For strains: TA 98, TA 100, TA 1535, TA 1537 and WP2 uvrA with S9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: pre-incubation

DURATION
- Pre-incubation period: no data
- Exposure duration: at least 48 hours
- Expression time (cells in growth medium): not applicable
- Selection time (if incubation with a selection agent): at least 48 hours
- Fixation time (start of exposure up to fixation or harvest of cells): not applicable

SELECTION AGENT (mutation assays): histidine and tryptophan
SPINDLE INHIBITOR (cytogenetic assays): not applicable
STAIN (for cytogenetic assays): not applicable

NUMBER OF REPLICATIONS: 3

NUMBER OF CELLS EVALUATED: no data

DETERMINATION OF CYTOTOXICITY
- Method: reduction of bacterial background lawn

OTHER EXAMINATIONS:
- Determination of polyploidy: not applicable
- Determination of endoreplication: not applicable
- Other: not applicable

OTHER: NaN3 was dissolved in distilled water; AF-2 ICR-191 and 2AA were dissolved in DMSO.
Evaluation criteria:
It is determined positive if the number of revertant colonies of the test agent treatment group depends on the dosage and increased twice or more as the negative control and reproducibility is acknowledged. Other cases are determined negative.

Unpredictable situations that may affect the credibility of the test, and not following the test plan.

For not following the test plan, the minimum glucose agar plating medium Lot No. AN550JM (manufactured on Oct. 3, 1997) was used in addition, while only AN510IM was to be used according to the plan. It was determined, however, that it would have no bad effect to the test.
There was no other unpredictable situation that may affect the credibility of the test.

No other situation that may adversely affect the credibility of the test, or no other incident of not following the test plan was acknowledged.
Statistics:
Statistical analyses were not done.

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: no data
- Effects of osmolality: no data
- Evaporation from medium: no data
- Water solubility: insoluble in water or oil
- Precipitation: Precipitation thought to be the test agent of this test was seen in 5 µg/plate regardless of presence/absence of S9 mix
- Other confounding effects: no data

RANGE-FINDING/SCREENING STUDIES:
5000 µg/plate as the maximum, the seven doses; 1000, 500, 100, 50, 10 and 5 µg/plate, were set. As a result, depositions which seem to be the test agent were seen in 5 µg/plate, regardless of the presence/absence of S9 mix.

COMPARISON WITH HISTORICAL CONTROL DATA:
It was confirmed that the positive control agent induces mutation in the test strains, and that the numbers of revertant colonies as well as the negative control value were within the range of the historical data of this institute, thus it was confirmed that the test was conducted properly.

ADDITIONAL INFORMATION ON CYTOTOXICITY: no data
Remarks on result:
other: all strains/cell types tested

Applicant's summary and conclusion

Conclusions:
It is determined that yttrium zirconium oxide does not have reverse mutation inducing capacity under the conditions of this test.