Registration Dossier

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In vitro:

Gene mutation (Bacterial reverse mutation assay/ Ames test): S. typhimurium strains: TA 100, TA 98, TA 1535, TA 1537; and E. coli WP2 strain: Negative with and without metabolic activation (according to OECD TG 471).

Mammalian mutagenicity (mouse lymphoma L5178Y cell): Negative with and without metabolic activation (according to OECD TG 476).

In vitro cytogenicity (chinese hamster CHL/IU cell): Negative with and without metabolic activation (equivalent or similar to OECD TG 473).

Link to relevant study records

Referenceopen allclose all

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
07 Nov 2011 - 22 Mar 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Keep the substance in cool and dark place; tightly closed, in refrigerator (1 - 10 °C); fill nitrogen after opening of package.
- Stability under test conditions: The test substance is stable. The stability is confirmed at the end of exposure using IR spectroscopy.
- Solubility and stability of the test substance in the solvent/vehicle: soluble in DMSO at 50 mg/mL
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No reactivity


TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Final preparation of a solid: Test material was measured and diluted in DMSO at 50 mg/mL. This solution was diluted sequencly in the appropriate concentration.

Target gene:
trp operon and his operon
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Metabolic activation system:
S9 mix, prepared from the livers of rats treated with phenobarbital and 5-6-benzoflavone
Test concentrations with justification for top dose:
Experiment 1 and 2: 39.1, 78.1, 156, 313, 652, and 1250 μg/mL were tested for TA1535 (up to the cytotoxic concentration)
Experiment 1 and 2: 156, 313, 652, 1250, 2500 and 5000 μg/mL were tested for TA100 , WP2uvrA, TA98 and TA1537
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: due to the limited solubility of the test substance in water, DMSO was selected as the vehicle
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
benzo(a)pyrene
furylfuramide
other: 6-chloro-9-[3-(2-chloroethylamino)propylamino]-2-methoxyacridine dihydrochloride for TA1537 without S9 mix, 2-amonoanthracene for TA1535 and WP2uvrA with S9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 minutes
- Exposure duration: 49.5 h for the first experiment and 48 h for the second experiment

NUMBER OF REPLICATIONS:
3 replication each in 2 independent experiments

NUMBER OF CELLS EVALUATED: all cells

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index
Evaluation criteria:
A test substance was considered positive in the Ames test if:
a) a more than 2-fold increase in the number of revertants was observed
b) the positive result was reproducible inspite of dose-related increase.
Statistics:
Mean values and standard deviations were calculated.
Key result
Species / strain:
S. typhimurium, other: TA 98, TA 100, TA 1535, TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
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:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
Preliminary test was performed with 19.5, 78.1, 313, 1250 and 5000 μg/mL with/without S9.
There was no reverse mutation observed in all species at all concentration. Furthermore, cytotoxicity was observed at 1250 μg/mL and more (TA1535) and at 5000 μg/mL (WP2urvA, TA98, TA100 and TA1537) with and without metabolic activation.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- Measurement of cytotoxicity used: number of revertant colonies

Table 1. Test results of the experiment 1 with or without S9 mix for triethoxy(methyl)silane

With or without S9 mix

Test substance concentration

(μg/plate)

Mean number of revertant colonies per plate

(Mean of 3 replicate ± SD)

Base-pair substitution type

Frameshift type

TA100

TA1535

WP2urvA

TA98

TA1537

-

0

84 ± 17.6

6 2.0±

20± 3.5

12± 3.8

5± 2.0

39.1

-

7± 1.5

-

-

-

78.1

-

6± 1.0

-

-

-

156

72± 12.1

8± 0.6

16± 4.9

13± 7.6

5± 0.6

313

87± 26.2

10± 3.5

17± 2.1

11± 4.6

5± 1.0

625

71± 10.2

7± 3.5

13± 2.0

9± 3.2

4± 1.2

1250

67± 7.4

7± 2.6

14± 5.1

14± 7.0

5± 1.5

2500

0± 0.0*

NT

10± 0.6*

0± 0.0*

0± 0.0*

5000

0± 0.0*

NT

5± 2.3*

0± 0.0*

0± 0.0*

Positive controls,

– S9 mix

Name

AF2

NaN3

AF2

AF2

ICR-191

Concentration (µg/plate)

0.01

0.5

0.01

0.1

1.0

Mean No. of colonies/plate

± SD

764± 8.1

350± 11.0

54± 21.5

365± 60.1

908± 69.8

+

0

80± 15.5

6± 1.2

15± 6.1

18± 4.9

10± 1.0

39.1

NT

8± 1.5

NT

NT

NT

78.1

NT

8± 2.5

NT

NT

NT

156

83± 12.1

8± 3.1

17± 3.1

15± 6.5

5± 1.5

313

93± 10.0

8± 1.5

13± 2.3

22± 7.0

6± 1.0

625

85± 9.0

8± 0.6

18± 5.0

14± 6.4

4± 2.3

1250

84± 8.2

6± 2.6*

11± 1.5

15± 5.7

6± 1.5

2500

51± 8.1*

NT

12± 3.5*

13± 4.7*

0 ± 0*

5000

0 ± 0*

NT

5 ± 2.0*

0 ± 0*

0 ± 0*

Positive controls,

+ S9 mix

Positive controls

B[a]P

2AA

2AA

B[a]P

B[a]P

Concentration (µg/plate)

5.0

2.0

10.0

5.0

5.0

Mean No. of colonies/plate

± SD

957 ± 93.6

254± 16.5

812± 66.4

250± 44.3

67± 3.1


Table 2. Test results of the experiment 2 with or without S9 mix for triethoxy(methyl)silane

With or without S9 mix

Test substance concentration

(μg/plate)

Mean number of revertant colonies per plate 

(Mean of 3 replicate ± SD)

-

Base-pair substitution type

Frameshift type

TA100

TA1535

WP2urvA

TA98

TA1537

128 ± 11.5

8 ± 1.5

13 ± 1.2

14 ± 2.5

7 ± 1.2

39.1

-

4 ± 2.5

-

-

-

78.1

-

6 ± 0.6

-

-

-

156

116 ± 7.8

8 ± 4.6

13 ± 2.0

17 ± 3.8

10 ± 4.4

313

98 ± 6.8

8 ± 6.7

12 ± 2.9

11 ± 4.2

6 ± 1.0

625

126 ± 14.8

6 ± 3.2

19 ± 3.5

12 ± 1.0

4 ± 0.0

1250

107 ± 12.5

4 ± 1.5*

12 ± 3.5

12 ± 6.1

6 ± 1.5

2500

0 ± 0.0*

-

12 ± 2.9*

5 ± 2.3*

0 ± 0.0*

5000

0 ± 0.0*

-

0 ± 0.0*

0 ± 0.0*

0 ± 0.0*

Positive controls,

– S9 mix

Name

AF2

NaN3

AF2

AF2

ICR-191

Concentration (µg/plate)

0.01

0.5

0.01

0.1

1.0

Mean No. of colonies/plate

± SD

638 ± 47.9

161 ± 3.2

70 ± 7.6

491 ± 31.2

1232 ± 27.8

+

0

118 ± 9.6

8 ± 1.5

22 ± 5.6

24 ± 9.9

7 ± 1.0

39.1

NT

7 ± 2.5

NT

NT

NT

78.1

NT

8 ± 2.5

NT

NT -

NT

156

127 ± 21.4

8 ± 1.5

14 ± 3.6

19 ± 2.5

7 ± 2.3

313

119 ± 13.7

8 ± 1.5

18 ± 9.9

23 ± 3.1

6 ± 3.2

625

123 ± 4.2

8 ± 2.6

15 ± 5.8

25 ± 4.2

8 ± 3.1

1250

114 ± 8.1

8 ± 2.9*

14 ± 2.1

17 ± 3.5

6 ± 1.0

2500

52 ± 17.3*

NT

7 ± 2.1

8 ± 1.7*

0 ± 0*

5000

0 ± 0*

NT

9 ± 2.6*

0 ± 0*

0 ± 0*

Positive controls,

+ S9 mix

Name

B[a]P

2AA

2AA

B[a]P

B[a]P

Concentration (µg/plate)

5.0

2.0

10.0

5.0

5.0

Mean No. of colonies/plate

± SD

937 ± 45.0

191 ± 13.0

776 ± 14.2

311 ± 24.0

97 ± 2.4

 

AF2: Furylfulamide

NaN3: sodium azide

ICR-191: 6-chloro-9-[3-(2-chloroethylamino)propylamino]-2-methoxyacridine dihydrochloride

B[a]P: Benzo(a)pyrene

2AA: 2-aminoanthracene

SD:  standard deviation

*: Growth inhibition

NT: This concentration was not tested.

Conclusions:
Under the conditions of the Ames test the substance was not mutagenic in any of the five strains (S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2 uvrA) tested with and without metabolic activation up to 1250 µg/plate for TA1535 and 5000 µg/plate for other strains.
Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
04 Nov 2011 - 23 Mar 2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
yes
Remarks:
200 metaphases scored, limited data on historical data provided (no values and range given), cell proliferation used as parameter for cytotoxicity (no RPD or RICC values given), no C-charts or X-bar charts provided
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Deviations:
no
GLP compliance:
yes
Type of assay:
in vitro mammalian chromosome aberration test
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Keep the substance in cool and dark place; tightly closed, in refrigerator (1 -10 °C); fill nitrogen after opening of package.
- Stability under test conditions: The test substance is stable. The stability is confirmed at the end of exposure using IR spectroscopy.
- Solubility and stability of the test substance in the solvent/vehicle: soluble in DMSO at 50 mg/mL
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No reactivity
Species / strain / cell type:
mammalian cell line, other: CHL/IU
Details on mammalian cell type (if applicable):
CELLS USED
- Source of cells: Health Science Research Resources Bank, Sennan-city, Japan
- Suitability of cells: yes
- Modal number of chromosomes: 25
- Cell cycle length, doubling time or proliferation index: within 15 - 20 h

MEDIA USED
- Type and identity of media including CO2 concentration if applicable: MEM supplemented with 10 v/v% bovine serum
- Properly maintained: yes
Metabolic activation:
with and without
Metabolic activation system:
S9 mix prepared from the livers of rats treated with phenobarbital and 5,6-benzoflavone
Test concentrations with justification for top dose:
Pre-experiment for cell proliferation inhibition test:
Short term treatment: 6 h exposure and 18 h fixation with and without S9 mix with concnetrations of 14.1, 28.1, 56.3, 113, 225, 450, 900 and 1800 μg/mL, and
Continuted treatment: 24 h and 48 h exposure without S9 mix with 14.1, 28.1, 56.3, 113, 225, 450, 900 and 1800 μg/mL


Main experiment:
450, 900 and 1800 μg/mL respective for short-term treatment (6 h) with and without metabolic activation and continuted treatments (24h, 48h) without metabolic activation
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Due to the limited solibility of the test substance in water, DMSO was selected as vehicle.
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
mitomycin C
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium
- Cell density at seeding (if applicable): 2 * 10000 cells/mL at seeding. After 3 days culture, the medium was changed and the cells were exposed to the test substance.

DURATION
- Exposure duration: 6 h for short-term treatment; 24 h and 48 h for continuted treatments

SPINDLE INHIBITOR (cytogenetic assays): 10 μg/mL Colcemid
STAIN: Giemsa
NUMBER OF REPLICATIONS: duplicates
NUMBER OF METAPHASE SPREADS ANALYSED PER DOSE (if in vitro cytogenicity study in mammalian cells): 200
Evaluation criteria:
A test substance was considered positive in the chromosoe aberration test if a) it induced 10% and more frequency of structural and numerical abnormality of chromosome, and b) dose responsibility and reproducibility was confirmed.
A test substance was considered false positive if it induced between 5 and 10% frequency of structual and numerical abnormality of chromosome.
A test substance was considered negative if it induced less tha 5% frequency of structual and numerical abnormality of chromosome.
Statistics:
Mean values and standard deviations were calculated.
Key result
Species / strain:
other: CHL/IU
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: precipitation was not observed at the end of the study, although it was observed above 900 μg/mL at the beginning of the study in all test system with or without metabolic activation.

RANGE-FINDING/SCREENING STUDIES:
The highest concentration was selected based on the results of cell groth inhibition test. The preliminary test was performed at 14.1, 28.1, 56.3, 113, 225, 450, 900, and 1800 μg/mL (equals to 10 mM) with/without S9 for short term treatmen t(6h) and without S9 mix for 24 h and 48 h treatments. Above 900 μg/mL, precipitate was observed at the beginning of the study. Since the minium inhibitionon the cell-growth ratio was observed, the highest dose was determined as 1800 μg/mL.

HISTORICAL CONTROL DATA (with ranges, means and standard deviation and confidence interval (e.g. 95%)
- Positive historical control data: not provided
- Negative (solvent/vehicle) historical control data: not provided

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- Measurement of cytotoxicity used: cell-growth ratio

Table 1. Test results for triethoxy(methyl)silane

Test item

Concentration

Cell-growth ratio

Aberrant cells

 

in µg/mL

in %

incl. gaps (%)

excl. gaps (%)

Structural aberrant cells

Nummeral aberrant cells

Exposure period 6 h, with S9 mix

DMSO

10% (v/v)

100

0.0

0.0

0.5

CP

14

105

78.5

78.5

0.0

Test substance

450

89

1.0

1.0

0.5

900

95

0.0

0.0

0.5

1800

89

0.5

0.5

0.0

Exposure period 6 h, without S9 mix

DMSO

10% (v/v)

100

0.0

0.0

0.5

MMC

0.075

109 

 22.5

22.5 

 0.5

Test substance

450

 100

 0.0

 0.0

 0.5

900

 104

 0.0

 0.0

 0.0

1800

 104

 0.0

 0.0

 0.5

Exposure period 24 h, without S9 mix

DMSO

10% (v/v)

100 

 0.5

 0.5

0.0 

MMC

0.050

 115

 29.5

 28.5

 0.0

Test substance

450

 94

 0.0

 0.0

 0.0

900

 94

 1.0

 1.0

 0.0

1800

 105

 0.0

 0.0

 0.0

Exposure period 48 h, without S9 mix

DMSO

10% (v/v)

 100

 0.5

0.5 

0.0

MMC

0.050

 115

 29.5

 28.5

0.0

Test substance

450

 94

 0.0

 0.0

0.0

900

 94

 1.0

 1.0

0.0

1800

 105

 0.0

 0.0

0.0

Positive controle:

MMC: Mitomycin C

CP: Cyclophosphamide

Conclusions:
Under the experimental conditions of the in vitro chromosome aberration test, the test substance did not induce structural chromosomal aberrations in Chinese hamster lung fibroblasts with and without metabolic activation.
Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to a test protocol that is comparable to the appropriate OECD test guideline. It was not compliant with GLP. The restriction was that the test concentration was insufficient considering no duplicates.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
yes
Remarks:
Insufficient test concentrations / no duplicates
GLP compliance:
no
Type of assay:
in vitro mammalian cell gene mutation tests using the thymidine kinase gene
Target gene:
TK locus
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
- Type and identity of media: Fischer's medium for leukemic cells of mice with 10% horse serum and sodium pyruvate.
- Properly maintained: yes
- Periodically checked for karyotype stability: yes
- Periodically "cleansed" against high spontaneous background: yes
Metabolic activation:
with and without
Metabolic activation system:
mouse liver S9
Test concentrations with justification for top dose:
Experiment I
with and without metabolic activation: 0.1, 0.2, 0.4, 0.8 and 1.6 μL/mL

Experiment II
without metabolic activation: 0.4, 0.8, 1.6 and 2.4 μL/mL
with metabolic activation: 0.4, 0.8, 1.6, 2.4 and 3.2 μL/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
0.1 and 0.5 µL/mL (without metabolic activation)
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Dimethylnitrosamine
Remarks:
0.1 and 0.5 µL/mL (with metabolic activation)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 4 hours
- Expression time (cells in growth medium): 3 days
- Selection time (if incubation with a selection agent): 10 days
- Fixation time (start of exposure up to fixation or harvest of cells): 13 days

SELECTION AGENT (mutation assays): BUdR (bromodeoxyuridine)

NUMBER OF REPLICATIONS: triplicates each of two independent experiments


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Evaluation criteria:
Increase of mutation frequency in a dose-dependent manner in comparison with historical control range.
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
50% growth inhibition at -S9 2.4 µL/mL; +S9: 3.2 µL/mL
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES: No data

ADDITIONAL INFORMATION ON CYTOTOXICITY: No data

Table 1: Experiment I - 4 h exposure

Concentration
[µg/mL]

Metabolic Activation

Cloning efficiency [%]

Relative Total Growth [%]

Mutants per 1E+06 surviving cells

Mutation factor

solvent control

-

100.00

100.00

3.30

1.00

negative control

-

92.90

80.30

4.20

1.27

0.1

-

93.30

103.70

10.90

3.30

0.2

-

78.40

71.10

15.50

4.70

0.4

-

92.50

58.50

6.40

1.94

0.8

-

109.80

80.20

3.90

1.18

1.6

-

79.60

51.50

4.90

1.48

EMS, 0.5

-

35.30

12.90

485.60

147.15

solvent control

+

100.00

100.00

6.50

1.97

negative control

+

95.00

84.80

3.00

0.91

0.1

+

67.50

75.00

12.10

3.67

0.2

+

60.60

64.70

8.30

2.52

0.4

+

85.80

68.10

13.60

4.12

0.8

+

91.80

89.60

14.40

4.36

1.6

+

100.30

50.70

7.50

2.27

DMN, 0.5

+

12.90

2.90

643.90

195.12

 

Table 2: Experiment II - 4 h exposure

Concentration
[µg/mL]

Metabolic Activation

Cloning efficiency [%]

Relative Total Growth [%]

Mutants per 1E+06 surviving cells

Mutation factor

solvent control

-

100.00

100.00

16.00

4.85

negative control

-

99.30

81.60

18.00

5.45

0.4

-

66.90

84.40

18.30

5.55

0.8

-

32.50

50.00

27.60

8.36

1.6

-

56.60

57.80

8.80

2.67

2.4

-

85.10

48.10

8.90

2.70

EMS, 0.

-

82.10

61.30

64.50

19.55

solvent control

+

100.00

100.00

13.00

3.94

negative control

+

70.40

67.10

37.30

11.30

0.4

+

121.10

84.10

12.00

3.64

0.8

+

118.80

122.90

17.00

5.15

1.6

+

115.00

85.70

19.20

5.82

2.4

+

116.00

111.50

12.10

3.67

3.2

+

125.40

45.00

15.00

4.55

DMN, 0.1

+

29.10

8.90

414.50

125.61

EMS   Ethyl methane sulphonate

DMN   Dimethylnitrosamine

Conclusions:
Interpretation of results: negative with and without metabolic activation.

In an in vitro mouse lymphoma L5178Y cells gene mutation test equivalent or similar to OECD 476 and not compliant with GLP, the test substance was found to be non-mutagenic. Appropriate solvent and positive controls were included and gave expected results.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Studies were chosen as key when the available study was of relevance and sufficient quality for classification, labelling and risk assessment. Other available data are included as supporting studies.

 

The key bacterial mutagenicity study on triethoxy(methyl)silane was conducted in compliance with GLP and according to OCED TG 471 (METI, 2012). No evidence for a test-substance related increase in the number of revertants was observed in Salmonella typhimurium TA 98, TA 100, TA 1535, TA 1537 and E. coli WP2uvrA strain.  The strains were treated with doses of 0.39 to 5.0 mg/plate with and without metabolic activation system. Appropriate positive and solvent controls were included and gave expected results. Under the conditions of this study, triethoxy(methyl)silane was concluded to be non-mutagenic in the Salmonella typhimurium strains(METI, 2012). This conclusion was further supported in two additional bacterial reverse mutation assays where no test-substance related increase in the number of revertants was observed in Salmonella typhimurium TA 98, TA100, TA1535, TA1537 and TA1538, treated with 0.1 to 5.0 mg/plate with and without metabolic activation system (Hazelton France, 1992e) or Salmonella typhimurium TA98, TA100, TA1535, TA1537, TA1538 andSaccharomyces cerevisiae, treated with doses of 0.001 to 5 µl/plate with and without metabolic activation system (Litton Bionetics, 1978), respectively.

The key in vitro cytogenicity study on triethoxy(methyl)silane was conducted in compliance with GLP and according to OECD TG 473 (METI, 2012). Triethoxy(methyl)silane did not cause a statistically significant dose-related increase in chromosome aberrations in Chinese hamster CHL/IU cells with or without metabolic activation. The test substance was therefore considered non-clastogenic in CHL/IU cells. Appropriate positive and solvent controls were included and gave expected results (METI, 2012). This conclusion was supported in an additional chromosome aberration test (Litton Bionetics, 1979). In the supporting study, no test-substance related increase in chromosome aberrations in mouse lymphoma L5178Y cells with or without metabolic activation were observed.

 

A key mammalian cell gene mutation study equivalent or similar to OECD TG 476 and which was conducted prior to the commencement of GLP is available for the registered substance. Triethoxy(methyl)silane was tested in the mouse lymphoma L5178Y cells in the absence and presence of metabolic activation. The cultures selected for cloning were treated with doses up to 2.4 µl/ml in the absence and 3.2 µl/ml in the presence of metabolic activation and exhibited no mutagenic potential in mouse lymphoma L5178Y cells. Appropriate positive and solvent controls were included and gave expected results (Litton Bionetics, 1978). 

 

 

In vivo testing is not required as no evidence for genetic toxicity was found in the in vitro studies.


Justification for classification or non-classification

Based on the available in vitro and in vivo data on mutagenicity of the registered substance, triethoxy(methyl)silane is not classified for mutagenicity according to Regulation (EC) 1272/2008.