Dichlorododecylmethylsilane

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2002-05-07 to 2002-08-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Freie und Hansestadt Hamburg Behörde für Arbeit Gesundheit und Soziales

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Trichloro(hexadecyl)silane

EC Number:

227-575-2

EC Name:

Trichloro(hexadecyl)silane

Cas Number:

5894-60-0

Molecular formula:

C16H33Cl3Si

IUPAC Name:

trichloro(hexadecyl)silane

Test material form:

liquid

Method

Target gene:

his 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:

other: uvr B-, rfa- (TA 98 & TA 100: pKM 101)

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 102

Additional strain / cell type characteristics:

other: wild-type, rfa-, pKM 101

Metabolic activation:

with and without

Metabolic activation system:

Aroclor induced rat liver S9-mix

Test concentrations with justification for top dose:

Preliminary toxicity test:
- 0.316, 1, 3.16, 10, 31.6, 100, 316, 1000, 3160 and 5000 µg/plate (without metabolic activation)
Experiment I:
- 10, 31.6, 100, 316 and 1000 µg/plate (with and without metabolic activation)
Experiment II:
- 10, 31.6, 100, 316 and 1000 µg/plate (with and without metabolic activation)

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

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: -S9-mix: sodium azide, 10 µg/plate (TA 100, TA 1535); 2-nitro-fluorene, 10 µg/plate (TA 98); 9-AA, 100 µg/plate (TA 1537); MMS, 1300 µg/plate (TA 102); +S9-mix: 2-AA, 2 µg/plate (TA 98, TA 102, TA 1537); CPA, 1500 µg/plate (TA 100, TA 1535)

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 in two independent experiments

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

Results and discussion

Test results

Test results 1

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

experiment I: at 1000 µg/plate (TA 100, TA 1535, TA 1537 without S9-mix; TA 1537 with S9-mix); experiment II: at 316 and 1000 µg/plate (all strains, without S9-mix)

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 316 and 1000 µg/plate (without S9-mix)

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

COMPARISON WITH HISTORICAL CONTROL DATA: Data were within range of historical control data

Any other information on results incl. tables

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 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*	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 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*	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 ethylene glycol dimethylether

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 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	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 ethylene glycol dimethylether

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative

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.