Dichloromethyltetradecylsilane

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:

2002-05-13 to 2002-09-19

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:

Dichloromethyloctylsilane

EC Number:

238-863-2

EC Name:

Dichloromethyloctylsilane

Cas Number:

14799-93-0

Molecular formula:

C9H20Cl2Si

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

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 102

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 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.

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 (all strains, with and without S9-mix); experiment II: at 1000 µg/plate (all strains, without S9-mix); at 316 µg/plate (TA 98, TA 1535. TA 1537, without S9-mix), =316 µg/plate (all strains, with 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:

experiment I: at 1000 µg/plate (with and without S9-mix); experiment II: =316 µg/plate (with and 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: Results 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 (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

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative

Dichloromethyloctylsilane 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 the test strains used.