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Toxicological information

Genetic toxicity: in vitro

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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:
2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report date:
2016

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
(21 Jul 1997)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
(BASF SE, Experimental Toxicology and Ecology, Ludwigshafen, Germany)
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Reference substance name:
Calcination products of titanium dioxide, tin monoxide, zinc oxide and dihydrogen wolframate
EC Number:
941-788-4
Molecular formula:
Ti 1 Sn 0,6 Zn 0,5 W 0,15 O 4
IUPAC Name:
Calcination products of titanium dioxide, tin monoxide, zinc oxide and dihydrogen wolframate
Test material form:
solid: particulate/powder
Details on test material:
Solid / red
stored at room temperature
The test substance was homogeneous by visual inspection.
The test item is not surface-treated or otherwise coated.

Method

Target gene:
his+ / trp+
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
phenobarbital and beta-naphthoflavone induced rat liver S9 microsomal fraction
Test concentrations with justification for top dose:
1st Experiment (Standard plate test with and without S9 mix): 0; 33; 100; 333; 1000; 2500 and 5000 μg/plate
2nd Experiment (Preincubation test with and without S9 mix): 0; 33; 100; 333; 1000; 2500 and 5000 μg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: Due to the limited solubility of the test substance in ultrapure water, DMSO was used as vehicle, which had been demonstrated to be suitable in bacterial reverse mutation tests and for which historical control data are available.
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (2-AA), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitro-o-phenylenediamine (NOPD), 9-aminoacridine (AAC), 4-nitroquinoline-N-oxide (4-NQO)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

Standard plate test:
- Exposure duration: 48 – 72 hours

Preincubation test:
- Preincubation period: 20 min
- Exposure duration: 48 – 72 hours


NUMBER OF REPLICATIONS: 3


DETERMINATION OF CYTOTOXICITY
- Method: decrease in the number of revertants, clearing or diminution of the background lawn, reduction in the titer


OTHER:
Titer determination: The titer was determined only in the experimental parts with S9 mix both for the negative controls (vehicle only) and for the two highest doses in all experiments.

Positive controls:

With S9 mix: 2-aminoanthracene (2-AA), 2.5 μg/plate, dissolved in DMSO / TA 1535, TA 100, TA 1537, TA 98; 60 μg/plate, dissolved in DMSO / Escherichia coli WP2 uvrA
Without S9 mix: N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 5 μg/plate, dissolved in DMSO / TA 1535, TA 100; 4-nitro-o-phenylenediamine (NOPD), 10 μg/plate, dissolved in DMSO / TA 98; 9-aminoacridine (AAC), 100 μg/plate, dissolved in DMSO / TA 1537; 4-nitroquinoline-N-oxide (4-NQO) (SIGMA, N-8141), 5 μg/plate, dissolved in DMSO / E. coli WP2 uvrA
Evaluation criteria:
Acceptance criteria:
Generally, the experiment is considered valid if the following criteria are met:
• The number of revertant colonies in the negative controls was within the range of the historical negative control data for each tester strain.
• The sterility controls revealed no indication of bacterial contamination.
• The positive control substances both with and without S9 mix induced a distinct increase in the number of revertant colonies within the range of the historical positive control data or above.
• Fresh bacterial culture containing approximately 10^9 cells per mL were used. For approval the titer of viable bacteria was ≥ 10^8 colonies per mL.

Assessment criteria:
The test substance is considered positive in this assay if the following criteria are met:
• A dose-related and reproducible increase in the number of revertant colonies, i.e. about doubling of the spontaneous mutation rate in at least one tester strain either without S9 mix or after adding a metabolizing system.

A test substance is generally considered non-mutagenic in this test if:
• The number of revertants for all tester strains were within the historical negative control range under all experimental conditions in at least two experiments carried out independently of each other.

Results and discussion

Test results
Key result
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
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: Test substance precipitation was found from about xxx μg/plate onward with and without S9 mix.

COMPARISON WITH HISTORICAL CONTROL DATA: yes

Any other information on results incl. tables

Table 1 (P=Precipitation)

Standard plate test Without metabolic activation
Dose
(μg/plate)
Mean
revertants
per plate
Standard
deviation
Factor Individual revertant colony
counts
Water - 9.7 3.2 - 11, 6, 12
TA 1535 Test item 33 11.7 3.2 1.2 14, 8, 13
100 9.7 2.1 1.0 8, 12, 9
333 11.3 3.8 1.2 13, 14, 7
1000 8.0 1.0 0.8 9, 7, 8
2500 12.7 5.1 1.3 7 P, 17 P, 14 P
5000 15.3 3.2 1.6 19 P, 13 P, 14 P
MNNG 5.0 4188.7 629.0 433.3 4773, 4270, 3523
TA 100 Water - 124.3 8.7 - 134, 117, 122
Test item 33 111.7 6.1 0.9 117, 105, 113
100 108.7 15.0 0.9 94, 124, 108
333 126.3 13.5 1.0 126, 113, 140
1000 118.0 5.6 0.9 113, 124, 117
2500 128.0 2.6 1.0 125 P, 129 P, 130 P
5000 119.3 12.5 1.0 105 P, 128 P, 125 P
MNNG 5.0 4078.3 173.9 32.8 3895, 4099, 4241
TA 1537 Water - 6.7 1.5 - 8, 7, 5
Test item 33 10.3 1.5 1.6 12, 9, 10
100 10.3 2.5 1.6 10, 8, 13
333 9.0 1.0 1.4 10, 9, 8
1000 6.0 1.0 0.9 7, 5, 6
2500 6.0 1.0 0.9 7 P, 5 P, 6 P
5000 6.3 3.2 1.0 5 P, 4 P, 10 P
AAC 100 931.7 171.0 139.8 852, 815, 1128
TA 98 Water - 26.0 5.2 - 29, 29, 20
Test item 33 22.7 3.5 0.9 23, 19, 26
100 24.0 4.6 0.9 20, 29, 23
333 24.7 2.5 0.9 25, 27, 22
1000 26.7 6.5 1.0 33, 20, 27
2500 25.3 2.9 1.0 27 P, 27 P, 22 P
5000 25.0 3.0 1.0 25 P, 22 P, 28 P
NOPD 10 1073.0 79.7 41.3 1120, 1118, 981
E. coli Water - 28.7 3.8 - 33, 26, 27
Test item 33 28.0 10.1 1.0 17, 37, 30
100 26.0 6.9 0.9 18, 30, 30
333 29.3 10.8 1.0 37, 34, 17
1000 27.3 5.0 1.0 22, 28, 32
2500 27.7 8.1 1.0 19 P, 29 P, 35 P
5000 26.3 6.5 0.9 26 P, 33 P, 20 P
4-NQO 5 1121.7 41.3 39.1 1144, 1147, 1074

Table 2 (P = precipitation)

Standard plate test With metabolic activation
Dose
(μg/plate)
Mean
revertants
per plate
Standard
deviation
Factor Individual revertant colony
counts
Water - 10.3 2.1 - 8, 12, 11
TA 1535 Test item 33 8.7 3.1 0.8 8, 12, 6
100 8.7 2.3 0.8 10, 6, 10
333 12.7 1.5 1.2 14, 11, 13
1000 13.0 3.6 1.3 17, 12, 10
2500 11.7 2.3 1.1 13 P, 13 P, 9 P
5000 12.3 3.2 1.2 10 P, 11 P, 16 P
2-AA 2.5 198.0 9.5 19.2 193, 192, 209
TA 100 Water - 135.3 9.3 - 131, 146, 129
Test item 33 110.7 11.9 0.8 116, 97, 119
100 149.7 11.0 1.1 156, 137, 156
333 130.0 16.5 1.0 139, 111, 140
1000 165.0 16.5 1.2 154, 184, 157
2500 142.0 10.4 1.0 147 P, 149 P, 130 P
5000 156.3 10.4 1.2 153 P, 148 P, 168 P
2-AA 2.5 1887.3 60.5 13.9 1929, 1915, 1818
TA 1537 Water - 6.3 2.5 - 6, 9, 4
Test item 33 7.7 3.2 1.2 10, 4, 9
100 7.7 1.5 1.2 9, 6, 8
333 9.0 3.5 1.4 7, 7, 13
1000 8.0 5.2 1.3 5, 5, 14
2500 7.0 3.6 1.1 4 P, 11 P, 6 P
5000 5.3 1.5 0.8 4 P, 5 P, 7 P
2-AA 2.5 159.7 20.7 25.2 156, 182, 141
TA 98 Water - 32.0 2.0 - 30, 34, 32
Test item 33 25.7 5.5 0.8 31, 20, 26
100 34.0 4.6 1.1 30, 39, 33
333 28.0 6.1 0.9 32, 21, 31
1000 33.0 6.2 1.0 35, 38, 26
2500 32.0 2.6 1.0 35 P, 30 P, 31 P
5000 32.0 6.2 1.0 25 P, 34 P, 37 P
2-AA 2.5 1582.7 59.8 49.5 1540, 1557, 1651
E. coli Water - 27.7 7.5 - 35, 20, 28
Test item 33 39.0 5.2 1.4 45, 36, 36
100 31.3 3.5 1.1 35, 31, 28
333 32.7 6.4 1.2 40, 30, 28
1000 27.0 2.0 1.0 29, 25, 27
2500 30.0 2.6 1.1 27 P, 31 P, 32 P
5000 20.0 2.6 0.7 19 P, 23 P, 18 P
2-AA 60 136.3 26.9 4.9 167, 125, 117

Applicant's summary and conclusion

Conclusions:
The substance is not mutagenic in bacteria.