Trimethoxyoctylsilane

Genetic toxicity: in vitro

Administrative data

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1997

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Trimethoxyoctylsilane

EC Number:

221-338-7

EC Name:

Trimethoxyoctylsilane

Cas Number:

3069-40-7

Molecular formula:

C11H26O3Si

IUPAC Name:

trimethoxyoctylsilane

Test material form:

liquid

Method

Target gene:

Histidine operon

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbital 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

Controls

Controls 1

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

Controls 2

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)

Controls 3

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

Controls 4

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

Results and discussion

Test results

Test results 1

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

Test results 2

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

Test results 3

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

Test results 4

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

Test results 5

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

Test results 6

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

Test results 7

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

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.

Any other information on results incl. tables

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

Applicant's summary and conclusion

Conclusions:

The substance RMS 808 MC has been tested according to OECD 471 and under GLP. No increase in the number of revertants was observed for the test substance tested up to cytotoxic or limit concentrations 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.