Trimethoxyoctadecylsilane

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:

14 Dec 2010 - 07 Jan 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

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)

Remarks:

Ministerium für Arbeit, Gesundheit und Soziales des Landes Nordrhein-Westfalen, Düsseldorf, Germany

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Hexadecyltrimethoxysilane

EC Number:

240-464-3

EC Name:

Hexadecyltrimethoxysilane

Cas Number:

16415-12-6

Molecular formula:

C19H42O3Si

IUPAC Name:

hexadecyl(trimethoxy)silane

Method

Target gene:

S. typhimurium strains: his operon
E. coli strain: trp operon

Species / strain

Species / strain 1

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not applicable

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

cofactor supplemented post-mitochondrial fraction (S9-mix), prepared from the livers of rats treated with Aroclor 1254

Test concentrations with justification for top dose:

Experiment I+II:
- 62, 185, 556, 1667, 5000 µg/plate (highest recommended concentration) (with and without metabolic activation)
Experiment III:
- 1000, 2000, 3000, 4000, 5000 µg/plate (with and without metabolic activation)

Vehicle / solvent:

- Vehicle/solvent used: acetone

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: -S9: sodium azide (NaN), 9-aminoacridine (9-AA), 2-nitrofluorene (2-NF), 4-nitroquinoline 1-oxide (4-NQO); +S9: 2-aminoanthracene (2-AA), benzo(a)pyrene (Ba(a)P)

Remarks:

NaN: 2 µg/plate (TA 100, TA 1535), 9-AA: 50 µg/plate (TA 1537), 2-NF: 4 µg/plate, 4-NQO: 1 µg/plate (E. coli WP2 uvrA), 2-AA: 7 µg/plate (TA 1535, TA 1537), 2 µg/plate (TA 100), 10 µg/plate (E. coli WP2 uvrA), Ba(a)P: 30 µg/plate (TA 98)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 h

NUMBER OF REPLICATIONS: triplicates in 3 independent experiments (test substance); six plates per experiment for the solvent control

DETERMINATION OF CYTOTOXICITY
- Method: growth of background lawn

Evaluation criteria:

A test substance producing no biologically relevant positive response in any one of the bacterial strains tested is considered to be non-mutagenic in this system. A biologically relevant response is described as follows: If the number of revertants is at least twice the spontaneous reversion rate for TA 1535, TA 98, TA 100 or WP2 uvrA (or three times for TA 1537) and/or if there is a concentration related increasing number of revertants over the range tested.

Statistics:

Mean values and standard deviations were calculated.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

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

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:

not examined

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

E. coli WP2 uvr A

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:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Precipitation of the test substance was observed at concentrations ≥ 1000 µg/plate.

COMPARISON WITH HISTORICAL CONTROL DATA
- Historical control data were given in the study report. The results of the solvent control cultures lied within the range of the historical control data.

OTHER
- Revertant counts higher than 1000 were counted and calculated as 1000.
- Study plan amendment: Due to invalid positive and solvent controls for the strains Salmonella typhimurium TA 100 and Escherichia coli WP2 uvrA parts of the first experiment had to be repeated (=second experiment).

Any other information on results incl. tables

Table 1: Mean values of experiment 1 and 2.

With or without S9-Mix	Test substance concentration (µg/plate)	Mean number of revertant colonies per plate (average of 3 plates ± Standard deviation)
		TA 1535	TA 1537	TA 98	TA 100	WP2 uvrA
–	0	9±3	4±3	20±4	207±34	17±6
–	62	7±3	3±1	23±6	202±30	16±3
–	185	10±2	3±3	24±3	219±26	19±4
–	556	6±3	8±3	20±1	222±39	15±5
–	1667, P	11±3	3±3	25±6	187±5	13±3
–	5000, P	9±5	5±3	27±3	200±9	12±2
Positive controls, –S9	Name	NaN3	9-AA	2-NF	NaN3	4-NQO
	Concentrations (µg/plate)	2	50	4	2	1
	Revertants per plate	677±107	328±45	363±64	1000±0	491±100
+	0	13±4	6±3	28±3	130±20	23±3
+	62	12±1	4±1	34±2	142±11	21±4
+	185	14±2	4±2	21±4	109±10	20±5
+	556	8±2	4±2	23±6	107±7	21±2
+	1667, P	12±2	4±3	28±6	129±12	19±4
+	5000, P	8±5	5±1	25±9	125±13	23±2
Positive controls, +S9	Name	2-AA	2-AA	B[a]P	2-AA	2-AA
	Concentrations (µg/plate)	7	7	30	2	10
	Revertants per plate	531±45	595±58	1000±0	1000±0	206±23

P: precipitation observed

 

Table 2: Results of experiment 3.

With or without S9-Mix	Test substance concentration (µg/plate)	Mean number of revertant colonies per plate (average of 3 plates ± Standard deviation)
		TA 1535	TA 1537	TA 98	TA 100	WP2 uvrA
–	0	9±2	4±1	21±4	105±12	20±6
–	1000, P	9±3	4±3	28±4	140±26	17±6
–	2000, P	13±5	1±1	22±4	134±33	28±11
–	3000, P	10±3	5±2	23±2	129±5	22±8
–	4000, P	10±4	2±2	19±1	137±21	25±1
–	5000, P	10±2	3±2	23±4	117±12	20±7
Positive controls, –S9	Name	NaN3	9-AA	2-NF	NaN3	4-NQO
	Concentrations (µg/plate)	2	50	4	2	1
	Revertants per plate	704±73	147±13	400±71	1000±0	613±41
+	0	9±2	4±1	21±4	105±12	20±6
+	1000, P	9±3	4±3	28±4	140±26	17±6
+	2000, P	13±5	1±1	22±4	134±33	28±11
+	3000, P	10±3	5±2	23±2	129±5	22±8
+	4000, P	10±4	2±2	19±1	137±21	25±1
+	5000, P	10±2	3±2	23±4	117±12	20±7
Positive controls, +S9	Name	2-AA	2-AA	B[a]P	2-AA	2-AA
	Concentrations (µg/plate)	7	7	30	2	10
	Revertants per plate	491±44	584±97	805±78	1000±0	274±103

 P: precipitation observed

Applicant's summary and conclusion

Conclusions:

In a study performed according to OECD 471 and in compliance with GLP no mutagenic effect was observed for the test substance tested up to the limit concentration in any of the test strains in three independent experiments with and without metabolic activation.