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Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Gene mutation (Bacterial reverse mutation assay / Ames test): the related substance trichloro(hexadecyl)silane (CAS 5894-60-0): negative with and without activation in Salmonella typhimurium strains TA98, TA 100, TA102, TA 1535 and TA 1537 (OECD TG 471) (LPT, 2002a)

Gene mutation (Bacterial reverse mutation assay / Ames test): the related substance dichloro(methyl)(octyl)silane (CAS 14799-93-0): negative with and without activation in Salmonella typhimurium strains TA98, TA 100, TA102, TA 1535 and TA 1537 (OECD TG 471) (LPT, 2002b)

Gene mutation (Bacterial reverse mutation assay / Ames test): read-across from related substance trimethoxy(octyl)silane (CAS 3069-40-7): negative with and without activation in Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537 and E. coli WP2 uvrA (OECD TG 471) (Dow Corning Corporation, 2003).

Cytogenicity in mammalian cells: negative with and without metabolic activation in Chinese hamster V79 cells (OECD TG 473) (BSL Bioservice, 2012a).

Cytogenicity in mammalian cells: read-across from related substance triethoxy(octyl)silane, (CAS 2943-75-1): negative in Chinese hamster ovary cells (OECD TG 473) (MA Bioservices 1997).

Mutagenicity in mammalian cells: read-across from related substance triethoxy(octyl)silane, (CAS 2943-75-1): negative in mouse lymphoma L5178Y cells (OECD TG 476) (BSL Bioservice, 2012b).

Mutagenicity in mammalian cells: read-across from related substance trichloro(hexadecyl)silane (CAS 5894-60-0): negative with and without metabolic activation in mouse lympoma L5178Y cells (OECD TG 476) (BSL Bioservice, 2012c).

Link to relevant study records

Referenceopen allclose all

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011-10-06 to 2011-12-27
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.5375 - In vitro Mammalian Chromosome Aberration Test
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.10 (Mutagenicity - In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, München, Germany
Type of assay:
in vitro mammalian chromosome aberration test
Species / strain / cell type:
Chinese hamster lung fibroblasts (V79)
Details on mammalian cell type (if applicable):
- Type and identity of media: MEM
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
Metabolic activation:
with and without
Metabolic activation system:
Liver S9 of Wistar phenobarbital and ß-naphthoflavone-induced rat liver S9 mix
Test concentrations with justification for top dose:
Pre-experiment: 0.020, 0.039, 0.078, 0.16, 0.31, 0.63, 1.25, 2.5, 5 and 10 mM (+/-MA); Expt I: 0.02, 0.04 and 0.06 mM (-MA); 0.100, 0.150 and 0.175 mM (+MA); Expt II: 0.03, 0.04 and 0.05 mM (-MA); 0.11, 0.14 and 0.16 mM (+MA)

Vehicle / solvent:
-Vehicle (s)/solvent(s) used: Tetrahydrofurane (final concentration of 1% v/v solvent)
-Justification for choice of solvent/vehicle: Due to the nature of the test item Octyltrichlorosilane could be dissolved in THF and diluted in cell culture medium (MEM) at a concentration of 10 mM. The solvent was compatible with the survival of the cells and the S9 activity.

Untreated negative controls:
yes
Remarks:
culture medium
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
without metabolic activation 400 and 900 µg/mL
Untreated negative controls:
yes
Remarks:
culture medium
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
with metabolic activation 0.83 µg/mL
Details on test system and experimental conditions:
TREATMENT TIME:
4 hours (Experiment I with and without metabolic activation, experiment II with metabolic activation)
20 hours (Experiment II without metabolic activation)

FIXATION INTERVAL: 20 hours (Experiment I and II with and without metabolic activation)
NUMBER OF REPLICATIONS: 2 independent experiments
NUMBER OF CELLS SEEDED: 1 x 10^4 - 5 x 10^4 cells
NUMBER OF CULTURES: two cultures per concentration
NUMBER OF CELLS SCORED: 200 cells per concentration (100 cells per culture)
DETERMINATION OF CYTOTOXICITY: Mitotic index, cell density
METABOLIC ACTIVATION: S9 mix included glucose-6-phospate and NADP as cofactors. S9 added so that the final protein concentration in cultures was 0.75 mg/ml.
Evaluation criteria:
There are several criteria for determining a positive result:
- a clear and dose-related increase in the number of cells with aberrations,
- a biologically relevant response for at least one of the dose groups, which is higher than the laboratory negative control range (0.0% - 4.0% aberrant cells (with and without metabolic activation)).


Statistics:
According to OECD guidelines, the biological relevance of the results is the criterion for the interpretation of results, a statistical evaluation of the results is not regarded as necessary.
Key result
Species / strain:
Chinese hamster lung fibroblasts (V79)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
No biologically relevant increase in the frequency of polyploid cells was observed.

Results of chromosome analysis
without metabolic activation
     Cytotoxicity Chromatid aberrations         Isochromatid aberrations       rel. Mitotic index (%) rel. Cell density (%)  Poly-ploidy mean % aberrant cells
Scored cells  gaps breaks  inter-changes  other  gaps breaks  inter-changes  other incl. Gaps excl. Gaps
Experiment I                              
negative control 200 - 2 1 0 1 1 0 0 0 91 101 1 2.5 1.0
solvent control 200 - 5 2 1 0 0 0 0 0 100 100 1 3.5 1.5
0.0025 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 89 n.d. n.d. n.d. n.d.
0.005 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 93 n.d. n.d. n.d. n.d.
0.01 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 95 n.d. n.d. n.d. n.d.
0.02 mM 200 no 1 3 0 0 2 0 0 0 97 101 1 2.5 1.0
0.04 mM 200 no 3 1 0 1 0 0 0 0 76 97 1 2.5 1.0
0.06 mM 200 yes   2 0 0 0 0 0 0 0 36 68 0 1.0 0.0
0.08 mM - yes   n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d.
0.10 mM - yes   n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d.
0.12 mM - yes   n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d.
EMS 900 µg/mL 200 - 7 13 8 1 1 0 1 1 84 95 1 15.0 11.0
Experiment II                                  
negative control 200 - 4 1 0 0 1 0 2 3 90 101 2 4.5 2.0
solvent control 200 - 1 0 0 0 0 0 1 0 100 100 0 1.0 0.5
0.0025 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 93 n.d. n.d. n.d. n.d.
0.005 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 94 n.d. n.d. n.d. n.d.
0.01 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 102 n.d. n.d. n.d. n.d.
0.02 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 99 n.d. n.d. n.d. n.d.
0.03 mM 200 no 3 1 0 0 0 0 0 0 85 100 6 2.0 0.5
0.04 mM 200 no 2 2 0 0 0 0 1 0 76 99 4 2.0 1.5
0.05 mM 200 yes 3 2 0 0 0 0 0 0 38 49 0 2.5 1.0
0.06 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 17 n.d. n.d. n.d. n.d.
0.07 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 8 n.d. n.d. n.d. n.d.
EMS 400 µg/mL 200 - 4 14 6 0 0 0 2 0 85 101 0 12.0 10.5

Results of chromosome analysis
with metabolic activation
     Cytotoxicity Chromatid aberrations         Isochromatid aberrations       rel. Mitotic index (%) rel. Cell density (%)  Poly-ploidy mean % aberrant cells
Scored cells  gaps breaks  inter-changes  other  gaps breaks  inter-changes  other incl. Gaps excl. Gaps
Experiment I                              
negative control 200 - 0 1 1 0 0 0 0 0 94 100 0 1.0 1.0
solvent control 200 - 1 2 1 0 0 0 0 0 100 100 0 1.5 1.0
0.025 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 106 n.d. n.d. n.d. n.d.
0.050 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 91 n.d. n.d. n.d. n.d.
0.100 mM 200 no 3 0 0 1 0 0 0 0 80 100 1 2.0 0.5
0.125 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 62 n.d. n.d. n.d. n.d.
0.150 mM 200 yes 1 0 0 0 1 0 0 0 63 93 1 1.0 0.0
0.175 mM 200 yes 2 1 0 0 0 0 0 0 43 73 1 1.5 0.5
0.200 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 16 n.d. n.d. n.d. n.d.
0.225 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 9 n.d. n.d. n.d. n.d.
0.250 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 0 n.d. n.d. n.d. n.d.
0.275 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 0 n.d. n.d. n.d. n.d.
0.300 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 21 n.d. n.d. n.d. n.d.
CPA 0.83 µg/mL 200 - 3 12 3 1 0 0 3 0 73 94 0 9.5 8.0
Experiment II                                  
negative control 200 - 6 3 1 2 0 0 0 0 99 100 1 4.5 2.0
solvent control 200 - 4 3 0 0 0 0 0 0 100 100 1 3.5 1.5
0.03 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 85 n.d. n.d. n.d. n.d.
0.06 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 114 n.d. n.d. n.d. n.d.
0.09 mM - no n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 86 n.d. n.d. n.d. n.d.
0.11 mM 200 no 0 1 0 0 0 0 0 0 79 100 1 0.5 0.5
0.13 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 61 n.d. n.d. n.d. n.d.
0.14 mM 200 yes 1 1 0 0 0 0 0 0 62 71 0 1.0 0.5
0.16 mM 200 yes 1 1 0 0 0 0 0 0 50 59 1 1.0 0.5
0.18 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 24 n.d. n.d. n.d. n.d.
0.20 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 15 n.d. n.d. n.d. n.d.
0.22 mM - yes n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 5 n.d. n.d. n.d. n.d.
CPA 0.83 µg/mL 200 - 7 10 4 0 1 0 2 1 85 100 1 11.0 8.0

n.d. not determined

Conclusions:
Trichloro(octyl)silane has been tested in a cytogenicity study conducted according to OECD TG 473 and in compliance with GLP. No evidence of the induction of chromosome aberrations or polyploidy was observed with or without metabolic activation when tested to cytotoxic concentrations in Chinese hamster V79 cells. It is concluded that octyltrichlorosilane is non-clastogenic (does not induce chromosome aberrations) under the conditions of the test.
Executive summary:

To investigate the potential of octyltrichlorosilane to induce structural chromosome aberrations in Chinese hamster V79 cells, an in vitro chromosome aberration assay was carried out.

The chromosomes were prepared 20 h after start of treatment with the test item. The treatment interval was 4 h with and without metabolic activation in Experiment I. In Experiment II the treatment interval was 4 h with and 20 h without metabolic activation. Duplicate cultures were treated at each concentration. 100 metaphases per culture were scored for structural chromosomal aberrations.

The test item Octyltrichlorosilane could be dissolved in THF and diluted in cell culture medium (MEM) at a concentration of 10 mM.

The following concentrations were evaluated for the microscopic analysis of chromosomal aberrations:

Experiment I:

without metabolic activation: 0.02, 0.04 and 0.06 mM

with metabolic activation: 0.100, 0.150 and 0.175 mM

Experiment II:

without metabolic activation: 0.03, 0.04 and 0.05 mM

with metabolic activation: 0.11, 0.14 and 0.16 mM

In the Experiments I and II no precipitation of the test item was seen with and without metabolic activation at all concentrations evaluated.

Toxic effects of the test item were noted in Experiment I without metabolic activation at a concentration of 0.06 mM, with metabolic activation at concentrations of 0.15 mM and higher.

In Experiment II without metabolic activation toxic effects of the test item were observed at a concentration of 0.05 mM, with metabolic activation toxic effects of the test item were noted at concentrations of 0.14 mM and higher.

In both experiments no biologically relevant increase of the aberration rates was noted after treatment with the test item with and without metabolic activation. The aberration rates of all dose groups treated with the test item were within the historical control data of the negative control.

In both experiments with and without metabolic activation no biologically relevant increase in the frequencies of polyploid cells was found after treatment with the test item as compared to the controls.

EMS (400 and 900 µg/mL) and CPA (0.83 µg/mL) were used as positive controls and induced distinct and biologically relevant increases in cells with structural chromosomal aberrations.

The positive controls induced the appropriate responses.

There was no evidence of test item Octyltrichlorosilane induced over background.

This study is classified as acceptable. This study satisfies the requirement for Test Guideline OPPTS 870.5375; OECD 473 for in vitro cytogenetic mutagenicity data. 

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-05-07 to 2002-08-26
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
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 102
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat liver S9
Test concentrations with justification for top dose:
10-1000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Abs. ethylene glycol

- Justification for choice of solvent/vehicle: Non toxic to bacteria
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 1535, TA 100 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
TA 98 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
TA 1537 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
TA 102 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-anthracene amide
Remarks:
TA 98, TA 102, TA 1537 (with activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
TA 100, TA 1535 (with activation)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION
- Preincubation period: 60 minutes
- Expression time (cells in growth medium): 48 hours

NUMBER OF REPLICATIONS: 3 plates per concentration

DETERMINATION OF CYTOTOXICITY
- Method: other: reduced background lawn and/or a reduction in the number of revertant colonies by more than 50% compared with the solvent control
Evaluation criteria:
The test chemical is positive if the number of revertants is significantly increased compared with the solvent control to at least 2-fold of the solvent control for TA 98, TA 100 and TA 102, and 3-fold of the solvent control for TA 1535 and TA 1537 in both experiments.

Positive results have to be reproducible and the histidine independence of the revertants has to be confirmed by streaking random samples on
histidine free agar plates.

Cytotoxicity is defined as a reduction in the number of colonies by more than 50% compared with the solvent control and/or a scarce background
lawn.
Statistics:
MANN and WHITNEY and Spearman's rank
Key result
Species / strain:
S. typhimurium, other: TA98, TA 100, TA102, TA 1535 and TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
316 µg/plate (all strains without metabolic activation)
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
COMPARISON WITH HISTORICAL CONTROL DATA: Data were within range of historical control data

Table 2: Dose range-finding study Number of revertants per plate (2 plates)

 

TA100

Conc.
(µg/plate)

Plate 1

Plate 2

Cytotoxic
(yes/no)

0*

137

137

No

0.316

140

145

No

1

144

143

No

3.16

132

106

No

10

127

116

No

31.6

121

126

No

100

109

107

No

316

142

122

No

1000

175

170

Yes

3160

0

0

Yes

5000

0

0

Yes

*solvent control with DMSO

Table 3: Experiment 1 Plate incorporation Number of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA102

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

0*

38

36

No

123.3

131.3

No

271.7

278.3

No

10

44.7

34

No

150.7

133.7

No

259.3

279.7

No

31.6

43

37

No

136.0

138

No

269.7

284

No

100

41.7

30

No

131.7

148.7

No

275

280.7

No

316

46

28.7

No

156.0

143

No

253.7

266.3

No

1000

47

31

No

147.7

132.7

Yes

291.3

258

No

Positive control

1041.7

987.3

No

1271.3

1267

No

1223

1219

No

*solvent control with DMSO

Table 3: Experiment 1 Plate incorporation Number of revertants per plate (mean of 3 plates)

 

TA1535

TA1537

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

0*

13.7

13

No

5

4

No

10

13.7

12.3

No

3.7

4.7

No

31.6

13

13

No

4.7

3

No

100

11.3

12

No

3

3.3

No

316

13.7

12.3

No

4

3.3

No

1000

12

11.7

Yes

4.7

5

Yes

Positive control

789

788.7

No

779.7

789.3

No

*solvent control with DMSO

Table 4: Experiment 2 Preincubation Number of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA102

Conc.
(
µg/plate)

— M

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

0*

37.3

38.3

No

114.7

134.7

No

277

259.3

No

10

41.3

28

No

108.3

104.7

No

252.3

281.3

No

31.6

36.3

37

No

134.3

114.7

No

256

268.7

No

100

33.3

37

No

120.3

134.3

No

248

278.7

No

316

46.7

30.7

Yes

132

151.3

Yes

260.3

272

Yes

1000

53.3

40.7

Yes

117.7

123.7

Yes

296.3

276

Yes

Positive control

637.7

654.7

No

997.3

976

No

1222

1226.3

No

*solvent control with DMSO

Table 4: Experiment 2 Preincubation Number of revertants per plate (mean of 3 plates)

 

TA1535

TA1537

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

0*

14

17.3

No

5

6

No

10

14.3

13.3

No

4.7

6

No

31.6

13.7

13.7

No

4.7

5

No

100

13

13

No

5

5.3

No

316

12

13.7

Yes

5.3

5.3

Yes

1000

14

14

Yes

4.3

5

Yes

Positive control

902.3

900

No

377.3

381.3

No

*solvent control with DMSO

Conclusions:
Trichloro(hexadecyl)silane has been tested in compliance with OECD 471, under GLP conditions. No increase in the number of revertant colonies compared with the solvent control was observed for the test substance in any of the Salmonella typhimurium strains TA98, TA 100, TA102, TA 1535 and TA 1537 when tested with and without metabolic activation in either the initial plate incorporation or the repeat pre-incubation assay. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.
Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2003-03-19 to 2003-04-01
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
1997
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay
Target gene:
Histidine operon
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:
Phenobarbital and Beta-Naphthoflavone induced rat liver S9
Test concentrations with justification for top dose:
3 µg/plate - 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Acetone

- Justification for choice of solvent/vehicle: Solubility properties and relative non-toxicity to bacteria
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 1535, TA 100 (without activation) 10 µg/plate
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylene-diamine 10 µg/plate in TA 98, 50 µg/plate in TA 1537
Remarks:
TA 1537, TA 98 (without activation)
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
WP2 uvrA (without activation) 4 µl/plate
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene 2.5 µg/plate (TA 1535, TA 1537, TA 98, TA 100), 10 µg/plate (WP2 uvrA)
Remarks:
All strains (with activation)
Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION

- Preincubation period: 60 minutes

- Expression time (cells in growth medium): 48 hours

NUMBER OF REPLICATIONS: 3 plates for each test concentration

DETERMINATION OF CYTOTOXICITY

- Method: Background lawn assessment, revertant colony counts
Evaluation criteria:
A result is considered positive if the number of revertants is significantly increased compared with the solvent control to at least 2-fold of the solvent control for TA 98, TA 100 and WP2 uvrA and 3-fold of the solvent control for TA 1535 and TA 1537 in both experiments.

A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration. An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent experiment.

Cytotoxicity is defined as a reduction in the number of colonies by >50% compared with the solvent control and/or a sparse background lawn.





Statistics:
No statistical evaluation of the data is required
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
5000 μg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
5000 μg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
5000 μg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
COMPARISON WITH HISTORICAL CONTROL DATA: With metabolic activation, the number of colonies did not quite reach the lower limit of historical control data in strain TA 1537, (negative and solvent control, exp 1), and in strain WP2 uvrA (negative control exp 1and 2, solvent control exp 1). Since these deviations are rather small, these effects are considered to be based upon biologically irrelevant fluctuations in the number of colonies.

Table 2:  Pre-toxicity test

 

TA98

TA100

TA1535

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

Negative control

23

29

No

108

107

No

10

12

No

0*

26

29

No

134

113

No

9

13

No

3

16

30

No

101

106

No

13

9

No

10

19

30

No

114

127

No

14

9

No

33

21

26

No

115

104

No

12

13

No

100

19

28

No

88

121

No

12

10

No

333

20

27

No

68

81

No

9

10

No

1000

16

26

No

76

84

No

9

10

No

2500

18

23

No

73

67

No

8

7

No

5000

17

20

No

52

58

Yes

5

6

Yes

Positive control

228

1495

No

1068

1629

No

697

211

No

*solvent control with acetone

Table 2:  Pre-toxicity test

 

TA1537

E. coli WP2 uvrA

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

Negative control

7

6

No

31

32

No

0*

4

5

No

29

31

No

3

3

5

No

28

25

No

10

5

5

No

28

34

No

33

5

5

No

27

33

No

100

4

7

No

32

34

No

333

3

4

No

30

27

No

1000

2

3

No

30

35

No

2500

3

3

No

31

32

No

5000

1

2

Yes

18

35

No

Positive control

50

226

No

804

215

No

*solvent control with acetone

Table 3: Experiment 1 Plate incorporation number of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA1535

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

Negative control

23

29

No

108

107

No

10

12

No

0*

26

29

No

134

113

No

9

13

No

33

21

26

No

115

104

No

12

13

No

100

19

28

No

88

121

No

12

10

No

333

20

27

No

68

81

No

9

10

No

1000

16

26

No

76

84

No

9

10

No

2500

18

23

No

73

67

No

8

7

No

5000

17

20

No

52

58

Yes

5

6

Yes

Positive control

228

1495

No

1068

1629

No

697

211

No

*solvent control with acetone

Table 3: Experiment 1 Plate incorporation - number of revertants per plate (mean of 3 plates)

 

TA1537

E. coli WP2 uvrA

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

Negative control

7

6

No

31

32

No

0*

4

5

No

29

31

No

33

5

5

No

27

33

No

100

4

7

No

32

34

No

333

3

4

No

30

27

No

1000

2

3

No

30

35

No

2500

3

3

No

31

32

No

5000

1

2

Yes

18

35

No

Positive control

50

226

No

804

215

No

*solvent control with acetone

Table 4: Experiment 2 Pre-incubation number of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA1535

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

Negative control

30

38

No

148

184

No

20

18

No

0*

28

35

No

154

187

No

17

17

No

33

30

40

No

150

199

No

17

19

No

100

28

40

No

146

214

No

17

16

No

333

23

32

No

177

198

No

18

16

No

1000

24

37

No

195

216

No

17

17

No

2500

28

35

No

188

242

No

21

15

No

5000

31

44

No

207

215

No

16

17

No

Positive control

239

1465

No

1536

1207

No

1479

299

No

*solvent control with acetone

Table 4: Experiment 2 Pre-incubation number of revertants per plate (mean of 3 plates)

 

TA1537

E. coli WP2 uvrA

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

Negative control**

9

11

No

38

33

No

0*

9

11

No

36

38

No

33

10

13

No

28

35

No

100

7

11

No

39

36

No

333

5

14

No

42

46

No

1000

6

10

No

31

46

No

2500

6

11

No

41

46

No

5000

5

12

No

40

41

No

Positive control

77

227

No

444

346

No

*solvent control with acetone

Conclusions:
The substance trimethoxy(octyl)silane has been tested according to OECD 461 and under GLP. No increase in the number of revertants was observed for the test substance tested up to cytotoxic concentration in any of the test strains either with or without metabolic activation in either the initial plate incorporation assay or the independent pre-incubation experiment . It is concluded that the test substance is not mutagenic to bacteria under the conditions of the test.

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-05-13 to 2002-09-19
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
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 102
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat liver S9
Test concentrations with justification for top dose:
10-1000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethylene glycol dimethylether

- Justification for choice of solvent/vehicle: The solvent was chosen because of its solubility properties and relative non toxicity to bacteria
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 1535, TA 100 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
TA 98 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
TA 1537 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
TA 102 (without activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-anthracene amide
Remarks:
TA 98, TA 102, TA 1537 (with activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
TA 100, TA 1535 (with activation)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION

- Preincubation period: 60 minutes

- Expression time (cells in growth medium): 48 hours

NUMBER OF REPLICATIONS: 3 plates for each test concentration

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth; background lawn assessment
Evaluation criteria:
A result is positive if the number of revertants is significantly increased compared with the solvent control to at least 2-fold of the solvent control for TA 98, TA 100 and TA 102 and 3-fold of the solvent control for TA 1535 and TA 1537 in both experiments.

Positive results have to be reproducible and the histidine independence of the revertants has to be confirmed by streaking on histidine-free agar plates.

Cytotoxicity is defined as a reduction in the number of colonies by >50% compared with the solvent control and/or a sparse background lawn.
Statistics:
MANN and WHITNEY and Spearman’s rank.
Key result
Species / strain:
S. typhimurium, other: TA98, TA 100, TA102, TA 1535 and TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
316 μg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
COMPARISON WITH HISTORICAL CONTROL DATA: Results were within range of historical control data


Table 2: Dose range-finding study Number of revertants per plate (TA 100 - MA)

 

TA100

Conc.
(µg/plate)

Plate 1

Plate 2

Cytotoxic
(yes/no)

0*

139

146

No

0.316

153

136

No

1

145

156

No

3.16

159

150

No

10

168

144

No

31.6

140

157

No

100

140

145

No

316

149

155

No

1000

0

0

Yes

3160

0

0

Yes

5000

0

0

Yes

*solvent control with Ethylene glycol dimethylether

Table 3: Experiment 1 Plate incorporation Number of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA102

Conc.
µg/plate

MA

+

MA

Cytotoxic
(yes/no)

MA

+

MA

Cytotoxic
(yes/no)

MA

+

MA

Cytotoxic
(yes/no)

0*

36.7

39.3

No

129.3

144

No

278.3

293.3

No

10

34.7

36.3

No

145.7

140.7

No

271

293

No

31.6

33.7

37

No

133.3

145

No

275

282

No

100

36.3

40.7

No

138.7

124.3

No

279.3

288.3

No

316

40.7

40.7

No

140.3

128.7

No

281.3

286.3

No

1000

0

0

Yes

0

0

Yes

0

0

Yes

Positive control

839.3

837.7

No

1168.7

1164

No

1186

1261.3

No

*solvent control with Ethylene glycol dimethylether

Table 3: Experiment 1 Plate incorporation Number of revertants per plate (mean of 3 plates)

 

TA1535

TA1537

Conc.
µg/plate

MA

+ MA

Cytotoxic
(yes/no)

MA

+

MA

Cytotoxic
(yes/no)

0*

15.3

12.7

No

5

6.3

No

10

14.7

11.7

No

4

4.7

No

31.6

14.3

11.7

No

4.3

4.3

No

100

14.7

14

No

2.7

5.7

No

316

14

13

No

5.7

5

No

1000

0

0

Yes

0

0

Yes

Positive control

538.7

558

No

545.3

549.7

No

*solvent control with Ethylene glycol dimethylether

Table 4: Experiment 2 Preincubation Number of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA102

Conc.
µg/plate

— MA

+

MA

Cytotoxic
(yes/no)

MA

+

MA

Cytotoxic
(yes/no)

MA

+

MA

Cytotoxic
(yes/no)

0*

35.3

36.7

No

129

145

No

277.3

289

No

10

36.3

38

No

116.3

124

No

279.7

269.7

No

31.6

37.3

30

No

129.3

114.7

No

287.3

274

No

100

27.7

27.3

No

140.3

112.7

No

268

266.3

No

316

30

0

Yes

136.3

0

Yes

258.7

0

Yes

1000

0

0

Yes

0

0

Yes

0

0

Yes

Positive control

1041

1070

No

1286.3

1292.3

No

1302

1306

No

*solvent control with Ethylene glycol dimethylether

Table 4: Experiment 2 Preincubation Number of revertants per plate (mean of 3 plates)

 

TA1535

TA1537

Conc.
µg/plate

— MA

+ MA

Cytotoxic
(yes/no)

— MA

+ MA

Cytotoxic
(yes/no)

0*

14.3

13

No

4

3.3

No

10

13

11.3

No

3

3.3

No

31.6

11

12

No

2.7

3

No

100

14

13.7

No

3.3

3

No

316

13

0

Yes

2.7

0

Yes

1000

0

0

Yes

0

0

Yes

Positive control

486

489

No

490

495

No

*solvent control with Ethylene glycol dimethylether

Conclusions:
Dichloro(methyl)(octyl)silane has been tested for mutagenicity to Salmonella typhimurium strain TA98, TA 100, TA102, TA 1535 and TA 1537 according to OECD TG 471, under conditions of GLP. No increase in the number of revertant colonies was observed with or without metabolic activation in any of the strains used in either the initial plate incorporation assay or the subsequent pre-incubation test. The test substance is non-mutagenic in test strains used.
Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1994.11.07 - 1997.12.24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
in vitro mammalian chromosome aberration test
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Details on mammalian cell type (if applicable):
- Type and identity of media:
- Properly maintained: yes/no
- Periodically checked for Mycoplasma contamination: yes
- Periodically checked for karyotype stability: yes/no
- Periodically "cleansed" against high spontaneous background: yes/no
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver S-9
Test concentrations with justification for top dose:
0.016 - 157 µg/ml
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle: no information provided
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
Ethanol
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
used with S9 metabolic activation 30 µg/ml
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
Ethanol
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: N-methyl-N-nitro-N-nitrosoguanidine (MNNG) dosed at 2 µg/ml
Remarks:
used without S9 activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 6 hours with and without S9 metabolic activation or up to 24 and 48 hours without S9
- Expression time (cells in growth medium): 18 hours
- Fixation time (start of exposure up to fixation or harvest of cells):

SPINDLE INHIBITOR (cytogenetic assays): Colcemid
STAIN (for cytogenetic assays): 5% Giemsa

NUMBER OF REPLICATIONS: 2

NUMBER OF CELLS EVALUATED: 200 per dose level

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cell growth inhibition

Statistics:
Fisher's exact test and the Cochran-Armitage test
Key result
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:



COMPARISON WITH HISTORICAL CONTROL

Chromosome aberration assay

Treatment µg/ml

S9 activation

Treatment /Harvest Time

Mitotic index

Cells scored

Cells with aberrations

Numerical      Structural

Negative control

    -

24

7.2

200

2.5

  0.5

Solvent control

    -

6/24

6.1

200

2.5

  0.5

A-137

 

 

 

 

 

 

 8.5

    -

6/24

6.8

200

1.0

  1.0

 11.3

    -

6/24

8.2

200

2.0

  0.5

15

    -

6/24

8.5

200

0.5

  2.0

20

    -

6/24

3.9

155

0.6

 0.0

Positive control

    -

6/24

5.2

200

1.5

27.0**

 

 

 

 

 

 

 

Negative control

    +

24

10.9

200

3.0

 0.5

Solvent control

    +

6/24

8.2

200

5.0

 0.5

A-137

 

 

 

 

 

 

21.3

    +

6/24

9.5

200

5.0

 0.5

28.3

    +

6/24

9.4

200

5.0

 0.0

37.6

    +

6/24

6.6

200

8.0

 1.5

50

    +

6/24

3.2

200

3.5

 1.0

Positive control

    +

6/24

3.0

200

8.5

43.0

 

 

 

 

 

 

 

Negative control

    -

24

12.1

200

0.5

 0.5

Solvent control

    -

24/24

9.1

200

0.0

 1.0

A-137

 

 

 

 

 

 

8.5

    -

24/24

7.6

200

0.0

 1.0

11.3

    -

24/24

11.6

200

1.0

 1.0

15

    -

24/24

11.7

200

1.5

 1.0

20

    -

24/24

 1.7

  37

0.0

 0.0

Positive control

    -

24/24

 5.9

200

1.5

20.5

 

 

 

 

 

 

 

Negative control

    -

48

5.0

200

0.0

 0.5

Solvent control

    -

48/48

4.0

200

0.0

 1.5

A-137

 

 

 

 

 

 

8.5

    -

48/48

4.1

200

0.0

 2.0

11.3

    -

48/48

3.1

200

0.0

 0.0

15

    -

48/48

2.0

200

1.0

 0.0

20

    -

48/48

2.0

200

0.5

 2.0

Positive control

    -

48/48

2.2

200

1.0

18.0

Conclusions:
Triethoxy(octyl)silane has been tested in a reliable in vitro cytogenetic assay according to OECD TG 473 and under GLP. The test substance did not induce statistically and biologically significant increases in the chromosomal aberration frequency of CHO (Chinese hamster ovary) cells. It is concluded that the test substance is negative for the induction of chromosome aberrations (not clastogenic) in vitro under the conditions of the test.

Endpoint:
in vitro gene mutation study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011-12-21 to 2012-03-20
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.17 (Mutagenicity - In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.5300 - In vitro Mammalian Cell Gene Mutation Test
Deviations:
no
Qualifier:
according to
Guideline:
other: IWGT Recommendations
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
(Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Germany)
Type of assay:
mammalian cell gene mutation assay
Target gene:
Thymidine kinase
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
- Type and identity of media: RPMI
- Properly maintained: Yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically "cleansed" against high spontaneous background: yes
Metabolic activation:
with and without
Metabolic activation system:
Liver S9 of Wistar Phenobarbital and ß-Naphthoflavone-induced rat liver S9 mix
Test concentrations with justification for top dose:
Pre-expt I: 0.2, 0.5, 2.5, 5.0, 7.5 and 10.0 mM (+/-MA); Pre-expt II: 0.01, 0.1, 1.0, 2.0, 5.0, 10.0 mM (-MA, 24 h exp); Expt I: 0.1, 0.2, 0.5, 1.0, 2.5, 5.0, 7.5 and 10.0 mM (+/-MA); Expt II: 0.15, 0.3, 0.7, 2.0, 4.0, 6.0, 8.0 and 10.0 mM (+MA); 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.10 and 0.20 mM (-MA)




Vehicle / solvent:
THF was used as solvent (0.35% THF v/v in the samples). To reach a final concentration of 0.35% THF v/v in the samples the test item stock solution was diluted in RPMI + 5% HS for short-term exposure or RPMI + 7.5% HS for long-term exposure. After adding the THF stock solution to cell culture medium precipitate formed.
The solvent was compatible with the survival of the cells and the activity of the S9 mix.
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
THF
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
with metabolic activation 3.5 µg/mL
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
without metabolic activation 200 µg/mL and 300 µg/mL
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
without metabolic activation 10 µg/mL
Details on test system and experimental conditions:
METHOD OF APPLICATION: dissolved in THF (0.35% THF v/v in the samples)
DURATION: 4 h (short-term exposure), 24 h (long-term exposure)
Expression time (cells in growth medium): 48 h
Selection time (if incubation with selection agent): about 14 days

SELECTION AGENT ( mutation assay) 5 µg/ml trifluorothymidine
NUMBER OF REPLICATIONS: two separate experiments (I+II) with single exposure; cells were seeded in 4 plates and evaluated
NUMBER OF CELLS SEEDED: 2000 cells per well
DETERMINATION OF CYTOTOXICITY: relative total growth (RTG)

ACTIVATION: S9 mix contained glucose-6-phosphate and NADP as co-factors, and sufficient S9 to give a final protein concentration in the cultures of 0.75 mg/ml
Evaluation criteria:
The test item is considered mutagenic if following criteria are met:
-The induced mutant frequency meets or exceeds the Global Evaluation factor (GEF) of 126 per 10^6 cells
- A dose-dependent increase in mutant frequency is detected.

Besides, combined with a positive effect in the mutant frequency, an increased occurrence of small colonies (≥40% of total colonies) is an indication for potential clastogenic effects and/or chromosomal aberrations.
According to the OECD guideline, the biological relevance is considered first for the interpretation of results. Statistical methods might be used as an aid in evaluation the test result.
A test item is considered to be negative if the induced mutant frequency is below the GEF and the trend test is negative.

Statistics:
The non-parametric Mann-Whitney test is applied to the mutation data to prove the dose groups for any significant difference in mutant frequency compared to the negative /solvent controls.
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
RTG of 14.6% and 9.7% without metabolic activation.
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid

Pre-experiment for toxicity with and without metabolic activation

Concentration (mM)

Number of cells 4 h after treatment

Number of cells 24 h after treatment

Number of cells 48 h after treatment

Suspension growth

Relative suspension growth

 

+S9

-S9

+S9

-S9

+S9

-S9

+S9

-S9

+S9

-S9

Negative control

271000

278000

946000

948000

1600000

1570000

15.1

14.9

89.8

103.6

307000

356000

105000

115000

1510000

1540000

15.9

17.7

94.1

123.3

Solvent control

307000

256000

104000

807000

1560000

1570000

16.2

12.7

100.0

100.0

339000

313000

112000

101000

1560000

1590000

17.5

16.1

0.2

284000

271000

77000

593000

1540000

1480000

11.9

8.8

70.4

61.1

0.5

307000

252000

876000

377000

1490000

1190000

13.1

4.5

77.5

31.2

2.5

289000

220000

728000

186000

1620000

637000

11.8

1.9

70.0

13.3

5.0

316000

225000

798000

137000

1550000

286000

12.4

0.9

73.4

6.0

7.5 (P)

303000

271000

650000

239000

1590000

850000

10.3

2.6

61.3

17.8

10.0 (P)

305000

244000

728000

183000

1580000

481000

11.5

1.4

68.3

10.0

Summary: Experiment 1 and 2 with metabolic activation

 

Treatment (mM)

RTG (%)

MF (mutants/106cells)

IMF (mutants/106cells)

Precipitate

 

Negative control

103.5

125.6

/

-

 

98.1

/

-

 

Solvent control

100.0

135.2

/

-

 

/

-

 

0.1

72.3

142.3

7.2

-

Exp 1

0.2

73.5

143.3

8.1

-

 

0.5

84.9

97.1

-38.1

-

 

1.0

63.7

182.8

47.6

-

 

2.5

67.1

144.4

9.2

-

 

5.0

87.2

117.6

-17.6

-

 

7.5

78.1

154.8

19.6

-

 

10.0

74.3

130.3

-4.8

+

 

Positive control

38.4

918.4

783.2

-

 

 

 

 

 

 

 

Treatment (mM)

RTG (%)

MF (mutants/106cells)

IMF (mutants/106cells)

Precipitate

 

Negative control

98.9

116.5

/

-

 

111.8

/

-

 

Solvent control

100.0

116.7

/

-

 

/

-

 

0.15

111.4

105.1

-11.6

-

Exp 2

0.3

96.2

131.1

14.4

-

 

0.7

75.7

128.5

11.8

-

 

2.0

42.3

220.5

103.8

-

 

4.0

72.7

138.8

22.2

-

 

6.0

58.9

170.6

53.9

-

 

8.0

74.1

134.6

17.9

+

 

10.0

76.4

154.9

38.2

+

 

Positive control

50.5

1141.0

1024.3

-

MF - mutant frequency

IMF = induced mutant frequency

RTG = relative total growth

Summary: Experiment 1 and 2 without metabolic activation

 

Treatment (mM)

RTG (%)

MF (mutants/106cells)

IMF (mutants/106cells)

Precipitate

 

Negative control

122.0

142.0

/

-

 

129.6

/

-

 

Solvent control

100.0

144.3

/

-

 

/

-

 

0.1

100.3

177.2

32.9

-

Exp 1

0.2

87.3

157.4

13.0

-

 

0.5

98.4

186.0

41.6

-

 

1.0

49.2

190.1

45.7

-

 

2.5

37.8*

179.4

35.1

-

 

5.0

37.2

179.3

35.0

-

 

7.5

17.1

224.1

79.8

+

 

10.0

14.6

264.7

120.4

+

 

Positive control 1

75.1

817.6

673.2

-

 

Positive control 2

85.2

564.1

419.7

-

 

 

 

 

 

 

 

Treatment (mM)

RTG (%)

MF (mutants/106cells)

IMF (mutants/106cells)

Precipitate

 

Negative control

145.4

110.6

/

-

 

122.8

/

-

 

Solvent control

100.0

109.3

/

-

 

/

-

 

0.001

114.6

108.6

-0.8

-

Exp 2

0.002

99.3

94.7

-14.6

-

 

0.005

103.4

120.0

10.6

-

 

0.01

62.1

121.8

12.5

-

 

0.02

82.5

160.0

50.6

-

 

0.05

98.6

108.4

-0.9

-

 

0.10

16.8

173.0

63.6

-

 

0.20

0.9

119.1

9.7

-

 

Positive control 1

21.3

2373.6

2264.2

-

 

Positive control 2

14.7

1826.6

1717.3

-

Conclusions:
Triethoxy(octyl)silane has been tested for mutagenicity to mammalian cells in a reliable study conducted according to OECD TG 476 and in compliance with GLP. No biologically relevant increase in mutation rate was found in mouse lymphoma L5178Y cells with or without metabolic activation in either the initial or the repeat experiment, up to limit and cytotoxic concentrations. The global evaluation factor was not exceeded at any concentration. In addition, colony sizing showed no clastogenic effects in either experiment. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.
Executive summary:

The test item triethoxy(octyl)silane was assessed for its potential to induce mutations at the mouse lymphoma thymidine kinase locus using the cell line L5178Y.

The selection of the concentrations used in the main experiments was based on data from the pre-experiments. In Experiment I 10.0 mM (with and without metabolic activation) was selected as the highest concentration. In Experiment II 10.0 mM (with metabolic activation) and 0.20 mM (without metabolic activation) were selected as the highest concentrations. Experiment I with and without metabolic activation and Experiment II with metabolic activation were performed as a 4 h short-term exposure assay. Experiment II without metabolic activation was performed as a 24 h long-term exposure assay.

THF was used as solvent (0.35% THF v/v in the samples). After adding the THF stock solution to cell culture medium precipitate formed.

The test item was investigated at the following concentrations:

Experiment I

with and without metabolic activation:

0.1, 0.2, 0.5, 1.0, 2.5, 5.0, 7.5 and 10.0 mM

Experiment II

with metabolic activation:

0.15, 0.3, 0.7, 2.0, 4.0, 6.0, 8.0 and 10.0 mM

and without metabolic activation:

0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.10 and 0.20 mM

Precipitation of the test item was noted in Pre-experiment Iwith and without metabolic activation, Pre-experiment II without metabolic activation, Experiment I with and without metabolic activation and in Experiment II with metabolic activation.

In Experiment I with metabolic activation the relative total growth (RTG) was 74.3% for the highest concentration (10.0 mM) evaluated. At two concentrations (1.0 mM and 2.5 mM) growth inhibition was observed with a RTG of 63.7% and 67.1%, respectively. However, considering all evaluated concentrations this effect showed no concentration relationship. The highest concentration evaluated without metabolic activation was 10.0 mM with a RTG of 14.6%. The Experiment without metabolic activation displayed a concentration related decrease in RTG starting at 1.0 mM with a RTG of 49.2%.

In Experiment II with metabolic activation the relative total growth (RTG) was 76.4% for the highest concentration (10.0 mM) evaluated. At two concentrations (2.0 mM and 6.0 mM) growth inhibition was observed with a RTG of 42.3% and 58.9%, respectively. However, considering all evaluated concentrations this effect showed no concentration relationship. The highest concentration evaluated without metabolic activation was 0.20 mM with a RTG of 0.9%. Due to high cytotoxicity the highest concentration was not considered for evaluation of mutagenicity. Experiment II without metabolic activation displayed a concentration related decrease in RTG starting at 0.1 mM with a RTG of 16.8%.

In Experiments I and II no biologically relevant increase of mutants were found after treatment with the test item (with and without metabolic activation).The Global Evaluation Factor (GEF; defined as the mean of the negative/vehicle mutant frequency plus one standard deviation; data gathered from ten laboratories) was not exceeded by the induced mutant frequency at any concentration.

No dose-response relationship was observed in Experiment I with metabolic activation and in Experiment II with and without metabolic activation. In Experiment I without metabolic activation a dose-response relationship was observed in the higher concentrations.

Additionally, in Experiments I and II colony sizing showed no clastogenic effects induced by the test item under the experimental conditions (with and without metabolic activation).

EMS, MMS and B[a]P were used as positive controls and showed distinct and biologically relevant effects in mutation frequency. Additionally, MMS and B[a]P significantly increased the number of small colonies, thus proving the efficiency of the test system to indicate potential clastogenic effects.

This study is classified as acceptable. This study satisfies the requirements for Test Guidelines OPPTS 870.5300, OECD 476 forin vitromutagenicity (mammalian forward mutation) data.

Endpoint:
in vitro gene mutation study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011-10-20 to 2012-01-31
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.17 (Mutagenicity - In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.5300 - In vitro Mammalian Cell Gene Mutation Test
Deviations:
no
Qualifier:
according to
Guideline:
other: IWGT Recommendations
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
(Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Germany)
Type of assay:
mammalian cell gene mutation assay
Target gene:
Thymidine kinase
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
- Type and identity of media: RPMI
- Properly maintained: Yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically "cleansed" against high spontaneous background: yes
Metabolic activation:
with and without
Metabolic activation system:
Phenobarbital and ß-Naphthoflavone-induced rat liver S9 mix
Test concentrations with justification for top dose:
Pre-experiment I with and without metabolic activation:
0.100, 0.500, 2.500, 5.000, 7.500 and 10.000 mM

Pre-experiment II without metabolic activation (24 h long-term exposure):
0.005, 0.010, 0.050, 0.100, 0.200 and 0.500 mM

Experiment I
with metabolic activation:
0.020, 0.040, 0.080, 0.100, 0.200, 0.300, 0.500, 0.800 mM

and without metabolic activation:
0.002, 0.005, 0.010, 0.020, 0.040, 0.080, 0.100, 0.200 mM

Experiment II
with metabolic activation:
0.015, 0.030, 0.050, 0.150, 0.250, 0.350, 0.450, 0.550, 1.150 mM

and without metabolic activation:
0.010, 0.020, 0.050, 0.100, 0.150, 0.200, 0.300, 0.350 mM





Vehicle / solvent:
Based on the results of the solubility test THF was used as solvent (0.5% THF v/v). Different test item stock solutions were prepared and added to the samples. To reach a final concentration of 0.5% THF v/v in the samples the test item stock solution was diluted in RPMI + 5% HS for short-term exposure or RPMI + 7.5% HS for long-term exposure. After adding the THF stock solution to cell culture medium precipitate formed. The pH value was adjusted to physiological range with 1 M NaOH. The solvent was compatible with the survival of the cells and the activity of the S9 mix.
Untreated negative controls:
yes
Remarks:
treatment medium
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
3.5 µg/ml; with metabolic activation
Untreated negative controls:
yes
Remarks:
treatment medium
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
without metabolic activation 200 µg/mL and 300 µg/mL
Untreated negative controls:
yes
Remarks:
treatment medium
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
without metabolic activation 10 µg/mL
Details on test system and experimental conditions:
METHOD OF APPLICATION: Dissolved in tetrahydrofuran and diluted with RPMI cell culture medium, where precipitate was formed.
DURATION: 4 h (short-term exposure), 24 h (long-term exposure)
Expression time (cells in growth medium): 48 h
Selection time (if incubation with selection agent): about 14 days

SELECTION AGENT ( mutation assay) 5 µg/ml trifluorothymidine
NUMBER OF REPLICATIONS: two separate experiments (I+II) with single exposure; cells were seeded in 4 plates and evaluated
NUMBER OF CELLS SEEDED: 2000 cells per well
DETERMINATION OF CYTOTOXICITY: relative total growth (RTG)
ACTIVATION: Phenobarbital and ß-Naphthoflavone-induced rat liver S9 mix included S9 to give a final protein concentration in the cultures of 0.75 mg/ml, and the following cofactors: 8 mM MgCl2; 33 mM KCl; 5 mM Glucose-6-phosphate; 5 mM NADP in 100 mM sodium-phosphate-buffer pH 7.4.
Evaluation criteria:
The test item is considered mutagenic if following criteria are met:
-The induced mutant frequency meets or exceeds the Global Evaluation factor (GEF) of 126 mutants per 10xE+06 cells
- A dose-dependent increase in mutant frequency is detected.

Besides, combined with a positive effect in the mutant frequency, an increased occurrence of small colonies (≥40% of total colonies) is an indication for potential clastogenic effects and/or chromosomal aberrations.
According to the OECD guideline, the biological relevance is considered first for the interpretation of results. Statistical methods might be used as an aid in evaluation the test result.
A test item is considered to be negative if the induced mutant frequency is below the GEF and the trend test is negative.

Statistics:
The non-parametric Mann-Whitney test is applied to the mutation data to prove the dose groups for any significant difference in mutant frequency compared to the negative /solvent controls.
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid

Table 1: Summary: Experiment I and II, with metabolic activation

Test Group

Conc. [mM]

RCE [%]

RTG

[%]

MF [mutants/ 106 cells]

IMF [mutants/ 106 cells]

GEF exceeded

Statistical Significance*

Precipitate

Experiment I

C1

0

105.4

128.9

90.7

/

/

/

-

C2

91.7

110.8

S1

0

100.0

100.0

81.7

/

/

/

-

S2

/

/

/

-

4

0.020

105.4

109.2

58.7

-23.0

-

-

-

5

0.040

97.5

110.7

106.2

24.6

-

-

-

6

0.080

98.2

108.6

77.2

-4.5

-

-

-

7

0.100

106.1

116.7

70.7

-11.0

-

-

-

8

0.200

88.8

95.3

93.2

11.5

-

-

+

9

0.300

98.9

83.9

105.5

23.8

-

-

+

11

0.500

83.8

25.0

87.7

6.0

-

-

+

12

0.800

60.6

7.6

78.7

-3.0

-

-

+

B[a]P

3.5

93.1

86.6

613.8

532.1

+

+

-

Experiment II

C1

0

103.6

104.9

91.8

/

/

/

-

C2

101.4

120.9

/

/

/

-

S1

0

100.0

100.0

109.7

/

/

/

-

S2

/

/

/

-

1

0.015

97.8

107.5

111.0

1.3

-

-

-

2

0.030

97.1

109.9

113.6

3.9

-

-

-

3

0.050

101.4

128.0

80.0

-29.7

-

-

-

4

0.150

101.4

127.1

134.0

24.2

-

-

-

5

0.250

93.5

95.1

129.9

20.2

-

-

-

6

0.350

92.8

63.6

172.7

63.0

-

+

-

7

0.450

33.1

2.2

132.6

22.9

-

-

+

8

0.550

67.6

7.8

127.7

17.9

-

-

+

14

1.150

91.4

8.3

112.0

2.3

-

-

+

B[a]P

3.5

90.6

76.8

742.1

632.4

+

+

-

Table 2: Summary: Experiment I and II, without metabolic activation

Test Group

Conc. [mM]

RCE [%]

RTG [%]

MF [mutants/ 10xE+06 cells]

IMF [mutants/ 10xE+06 cells]

GEF exceeded

Statistical Significance*

Precipitate

Experiment I

C1

0

93.5

91.1

58.6

/

/

/

-

C2

99.7

112.4

/

/

/

-

S1

0

100.0

100.0

62.5

/

/

/

-

S2

/

/

/

-

1

0.002

94.2

109.4

56.8

-5.8

-

-

-

2

0.005

96.9

111.0

46.8

-15.7

-

-

-

3

0.010

90.8

91.0

82.8

20.2

-

-

-

4

0.020

109.2

109.3

44.0

-18.5

-

-

-

5

0.040

91.5

90.5

77.5

14.9

-

-

-

6

0.080

95.6

89.6

78.3

15.7

-

-

-

7

0.100

99.7

79.8

69.9

7.4

-

-

-

8

0.200

74.4

16.8

80.4

17.8

-

-

+

EMS

300

87.4

92.4

506.6

444.1

+

+

-

MMS

10

86.7

83.3

416.3

353.8

+

+

-

Experiment II

 

 

C1

0

91.5

134.0

83.4

/

/

/

-

C2

98.6

142.4

/

/

/

-

S1

0

100.0

100.0

68.6

/

/

/

-

S2

/

/

/

-

4

0.010

102.8

100.6

53.1

-15.5

-

-

-

5

0.020

89.4

83.2

89.3

20.7

-

-

-

6

0.050

84.4

93.7

106.1

37.5

-

-

-

7

0.100

96.5

85.6

71.5

2.9

-

-

-

8

0.150

90.8

91.8

95.4

26.8

-

-

-

9

0.200

89.4

38.9

87.3

18.6

-

-

-

11

0.300

95.7

34.8

57.6

-11.0

-

-

+

12

0.350

98.6

6.9

70.3

1.7

-

-

+

EMS

200

70.9

42.5

1763.5

1694.9

+

+

-

MMS

10

61.7

42.1

776.2

707.6

+

+

-

C: Negative Controls

S: Solvent Controls

RCE: Relative Cloning Efficiency = [(mean value positive cultures / mean value positive cultures of corresponding controls) x 100]

RTG: Relative Total Growth = (RSG x RCE)/100

MF: Mutant Frequency = {-ln [negative cultures/total wells (selective medium)] / -ln [negative cultures/total wells (non selective medium)]}x800

IMF: Induced Mutant Frequency = mutant frequency sample – mean value mutant frequency corresponding controls

GEF: Global Evaluation Factor (126); +: GEF exceeded, -: GEF not exceeded

*Statistical significant difference in mutant frequency compared to negative/solvent controls (Mann Whitney test , p<0.05). +: significant; -not significant

B[a]P: Benzo[a]pyrene [μg/ml]

EMS: Ethylmethanesulphonate [μg/ml]

MMS: Methylmethanesulphonate [μg/ml]

Conclusions:
Trichloro(hexadecyl)silane has been tested in a study conducted according to OECD 476 and in compliance with GLP. No test-substance induced increase in the mutant frequency was observed with or without metabolic activation when the substance was tested up to cytotoxic concentration in L5178Y cells. Appropriate solvent, negative and positive controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to mammalian cells under the conditions of the test.
Executive summary:

The test item trichloro(hexadecyl)silane was assessed for its potential to induce mutations at the mouse lymphoma thymidine kinase locus using the cell line L5178Y.

The selection of the concentrations used in the main experiments was based on data from the pre-experiments. In experiment I 0.800 mM (with metabolic activation) and 0.200 mM (without metabolic activation) were selected as the highest concentrations. In experiment II 1.150 mM (with metabolic activation) and 0.350 mM (without metabolic activation) were selected as the highest concentrations. Experiment I with and without metabolic activation and experiment II with metabolic activation were performed as a 4 h short-term exposure assay. Experiment II without metabolic activation was performed as a 24 h long-term exposure assay.

The test item was dissolved in tetrahydrofuran (THF) and diluted in RPMI + 5% HS for short-term exposure or RPMI + 7.5% HS for long-term exposure. After adding the THF stock solution to cell culture medium precipitate formed.

The test item was investigated at the following concentrations:

Experiment I

with metabolic activation:

0.020, 0.040, 0.080, 0.100, 0.200, 0.300, 0.500, 0.800 mM

and without metabolic activation:

0.002, 0.005, 0.010, 0.020, 0.040, 0.080, 0.100, 0.200 mM

Experiment II

with metabolic activation:

0.015, 0.030, 0.050, 0.150, 0.250, 0.350, 0.450, 0.550, 1.150 mM

and without metabolic activation:

0.010, 0.020, 0.050, 0.100, 0.150, 0.200, 0.300, 0.350 mM

Precipitation of the test item was noted in pre-experiment I and II and in experiment I and II with and without metabolic activation.

Growth inhibition was observed in experiment I and II with and without metabolic activation.

In experiment I with metabolic activation the relative total growth (RTG) was 7.6% for the highest concentration (0.800 mM) evaluated. The highest concentration evaluated without metabolic activation was 0.200 mM with a RTG of 16.8%. In experiment II with metabolic activation the relative total growth (RTG) was 8.3% for the highest concentration (1.150 mM) evaluated. The highest concentration evaluated without metabolic activation was 0.350 mM with a RTG of 6.9%.Concentrations with RTG values below 10% were not considered for evaluation of mutagenicity.

In experiment I and II no biologically relevant increase of mutants was found after treatment with the test item (with and without metabolic activation).The Global Evaluation Factor (GEF; defined as the mean of the negative/vehicle mutant frequency plus one standard deviation; data gathered from ten laboratories) was not exceeded by the induced mutant frequency at any concentration. Concentrations with RTG values below 10% were not considered for evaluation of mutagenicity.

No dose-response relationship was observed.

In experiment I and II colony sizing showed no clastogenic effects induced by the test item under the experimental conditions (with and without metabolic activation).

EMS, MMS and B[a]P were used as positive controls and showed distinct and biologically relevant effects in mutation frequency. Additionally, MMS and B[a]P significantly increased the number of small colonies, thus proving the efficiency of the test system to indicate potential clastogenic effects.

This study is classified as acceptable. This study satisifies the requirements for Test Guidelines OPPTS 870.5300, OECD 476 for in vitro mutagenicity (mammalian forward mutation) data.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

No bacterial mutagenicity data are available for trichloro(octyl)silane. Bacterial mutagenicity studies are, however, available for the related substances, trichloro(hexadecyl)silane and dichloro(methyl)(octyl)silane. Data are also available for two other related substances, triethoxy(octyl)silane, (CAS 2943 -75 -1) and trimethoxy(octyl)silane (CAS 3069-40-7).

Trichloro(hexadecyl)silane has been tested in a bacterial mutagenicity study conducted according to OECD TG 471 and under GLP conditions. No evidence of mutagenicity was observed with or without metabolic activation in Salmonella typhimurium strains TA 98, TA 100, TA102, TA 1535 and TA 1537 (LPT, 2002a).

Dichloro(methyl)(octyl)silane has been tested in a bacterial mutagenicity study conducted according to OECD TG 471 and under GLP. No evidence of mutagenicity was observed with or without metabolic activation in Salmonella typhimurium strains TA 98, TA 100, TA102, TA 1535 and TA 1537 (LPT, 2002b).

Trimethoxy(octyl)silane has been tested in a bacterial mutagenicity study conducted according to a protocol similar to OECD TG 471. No evidence of mutagenicity was observed with or without metabolic activation in Salmonella typhimurium strains TA98, TA 100, TA 1535, TA1537 and TA 1538 (Dow Corning Corporation, 2003).

Triethoxy(octyl)silane has been tested in a cytogenicity study conducted according to OECD TG 473 and under GLP. No evidence of the induction of chromosome aberration was observed with or without metabolic activation in CHO K1 cells (MA Bioservices, 1997).

Trichloro(octyl)silane has been tested in a cytogenicity study conducted according to OECD TG 473 and under GLP (BSL Bioservice, 2012a). No evidence of the induction of chromosome aberrations or polyploidy was observed with or without metabolic activation when tested to cytotoxic concentrations in Chinese hamster V79 cells. It is concluded that trichloro(octyl)silane is non-clastogenic (does not induce chromosome aberrations) under the conditions of the test.

No mammalian mutagenicity data in vitro are available for trichloro(octyl)silane. However, data are available for the analogue substances triethoxy(octyl)silane and trichloro(hexadecyl)silane.

Triethoxy(octyl)silane has been tested for mutagenicity to mammalian cells in a reliable study conducted according to OECD TG 476 and in compliance with GLP (BSL Bioservice, 2012b). No biologically relevant increase in mutation rate was found in mouse lymphoma L5178Y cells with or without metabolic activation in either the initial or the repeat experiment, up to limit and cytotoxic concentrations. The global evaluation factor was not exceeded at any concentration. In addition, colony sizing showed no clastogenic effects in either experiment. It is concluded that the test substance is negative for mutagenicity to L5178Y cells under the conditions of the test.

Trichloro(hexadecyl)silane has been tested in a mammalian mutagenicity study conducted according to OECD TG 476 and in compliance with GLP (BSL Bioservice, 2012c). No biologically relevant increase in the mutant frequency was observed when L5178Y cells were treated in the presence or the absence of metabolic activation. Appropriate solvent, negative and positive controls were included and gave expected results. It is concluded that the test substance is negative for the induction of mutations in L5178Y cells under the conditions of the test.

In vivo testing is not needed as no positive results were observed in vitro.


Justification for classification or non-classification

Based on the available in vitro genotoxicity data, trichloro(octyl)silane is not classified for mutagenicity according to Regulation (EC) No 1272/2008.