Reaction mass of disodium oxide and zirconium dioxide and silicon dioxide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-05-07 to 2010-05-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of silicon dioxide and zirconium dioxide

EC Number:

910-388-1

Molecular formula:

not applicable (multi-constituent substance)

IUPAC Name:

Reaction mass of silicon dioxide and zirconium dioxide

Details on test material:

- Name of test material (as cited in study report): Silica-Zirkonia Filler
- Physical state: White powder
- Batch: IT-253
- Analytical purity of components: 72.4% silicon dioxide (CAS No. 7631-86-9) and 26.0% zirconium dioxide (CAS No. 1314-23-4) and a not stated percentage of disodium oxide (CAS No. 1313-59-3)
- Storage: at room temperature in the dark
- Stability: stable under storage conditions
- Expiry date: 20 Nov 2010
- not soluble in water

Method

Target gene:

S. typhimurium: Histidine operon
E. coli: Tryptophan operon

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbital (80 mg/kg bw) and ß-naphthoflavone (100 mg/kg bw) induced rat liver S9-mix

Test concentrations with justification for top dose:

3, 10, 33, 100, 333, 1000, 3330, and 5000 µg/plate with and without 3.6% S9-mix for dose range finding test
3, 10, 33, 100, 333, 1000, 3330, and 5000 µg/plate with and without 5% S9-mix for experiment 1
33, 100, 333, 1000 and 3330 µg/plate with and without 10% S9-mix for experiment 2

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

0.1 mL DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2 aminoanthracene: 2.5 µg/plate for TA 1535 and TA 1537, 1 µg/plate for TA 98 and TA 100 and 10 µg/plate for WP2 uvrA

Remarks:

with 5% S9-mix

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

0.1 mL DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2 aminoanthracene: 2.5 µg/plate for TA 1535 and TA 100, 1 µg/plate for TA 98, 5 µg/plate for TA 1537 and 10 µg/plate for WP2 uvrA

Remarks:

with 10% S9-mix

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

0.1 mL DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without S9-mix Migrated to IUCLID6: 5 µg/plate for TA 1535

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

0.1 mL DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

without S9-mix Migrated to IUCLID6: 60 µg/plate for TA 1537

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

0.1 mL DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

without S9-mix Migrated to IUCLID6: 10 µg/plate for TA 98

Controls 6

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

0.1 mL DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Remarks:

without S9-mix Migrated to IUCLID6: 650 µg/plate for TA 100

Controls 7

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

0.1 mL DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

without S9-mix Migrated to IUCLID6: 10 µg/plate for WP2 uvrA

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 ± 4 hours

NUMBER OF REPLICATIONS: triplicate

NUMBER OF CELLS EVALUATED: if less than 40 colonies/plate were present they were counted manually, if more than 40 colonies were present, they were counted automatically with a Biocount 4000 Pro-S colony counter.

DETERMINATION OF CYTOTOXICITY
- Method: reduction of the bacterial background lawn, increase in the size of the microcolonies and reduction of the revertant colonies

Evaluation criteria:

A test substance is considered negative (not mutagenic) in the test if:
a) The total number of revertants in tester strain TA1OO is not greater than two (2) times the concurrent control, and the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2uvrA is not greater than three (3) times the concurrent control.
b) The negative response should be reproducible in at least one independently repeated experiment.

A test substance is considered positive (mutagenic) in the test if:
a) The total number of revertants in tester strain TA1OO is greater than two (2) times the concurrent control, or the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2uvrA is greater than three (3) times the concurrent control.
b) In case a repeat experiment is performed when a positive response is observed in one of the tester strains, the positive response should be reproducible in at least one independently repeated experiment.

The preceding criteria were not absolute and other modifying factors might enter into the final evaluation decision.

Results and discussion

Test results

Species / strain:

other: E. coli WP2uvrA and 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

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: at concentrations of 3330 and 5000 µg/plate

RANGE-FINDING/SCREENING STUDIES: tested in the tester strains TA100 and WP2uvrA with concentrations of 3, 10, 33, 100, 333, 1000, 3330 and 5000 pg/plate in the absence and presence of S9-mix.

COMPARISON WITH HISTORICAL CONTROL DATA: In range of historical control data from the laboratory.

Any other information on results incl. tables

Table 1: Maximum number of revertants from experiment 1

	Maximum number of revertants
	Solvent control		Positive control		Treatment (at dose level [µg/mL])
Strain	With S9	Without S9	With S9	Without S9	With S9	Without S9
TA 1535	6	5	332	960	10 (100)	9 (333)
TA 1537	3	4	364	268	4 (333)	5 (33)
TA 98	19	13	1027	1131	25 (1000)	18 (100)
TA 100	93	95	1197	603	104 (5000)	101 (33)
WPA2uvrA	20	18	376	1082	23 (1000)	25 (333)

 

Table 2: Maximum number of revertants from experiment 2

	Maximum number of revertants
	Solvent control		Positive control		Treatment (at dose level [µg/mL])
Strain	With S9	Without S9	With S9	Without S9	With S9	Without S9
TA 1535	6	12	224	942	10 (333)	13 (33)
TA 1537	3	4	283	296	4 (33)	5 (100)
TA 98	25	15	694	1098	27 (3330)	22 (100)
TA 100	64	106	1239	1097	74 (3330)	109 (333)
WPA2uvrA	17	10	331	1045	20 (1000)	20 (333)

 

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative