Hexachlorodisilane

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1981-03-10

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The restrictions were that only four dose concentrations were tested with single replicates and the range of strains does not comply with current guidelines.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

only 4 doses no duplicates; the range of strains does not comply with current guidelines.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Trichlorosilane

EC Number:

233-042-5

EC Name:

Trichlorosilane

Cas Number:

10025-78-2

Molecular formula:

Cl3HSi

IUPAC Name:

Trichlorosilane

Method

Species / strain

Species / strain / cell type:

bacteria, other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100

Metabolic activation:

with and without

Metabolic activation system:

Aroclor induced rat liver S9

Test concentrations with justification for top dose:

0.5, 5, 100 and 500 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle: none given

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

ethanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

without activation Migrated to IUCLID6: strain TA 1537

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

without activation Migrated to IUCLID6: strains TA 98 and TA 1538

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-anthramine

Remarks:

all strains with activation

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

ethanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without activation Migrated to IUCLID6: TA 1535 and TA 100

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48-72 hours
- Expression time (cells in growth medium): 48-72 hours
- Fixation time (start of exposure up to fixation or harvest of cells): 48-72 hours


NUMBER OF REPLICATIONS: One


DETERMINATION OF CYTOTOXICITY
- Method: other: reduction in number of revertants (reviewers assessment)

Evaluation criteria:

A reproducible dose-responsive increase in the number of revertants over 3 concentrations to at least twice the solvent control (TA 1535, 1537, 1538) or an increase over 3 concentrations with the highest increase twice the solvent control is considered posiitve.

Statistics:

The number of colonies was counted using a Model C111 Automated colony counter. Each count is listed as the average of 10 replicate counts on each plate.

Results and discussion

Test results

Species / strain:

bacteria, other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Other confounding effects: hydrolysis of test compound may have occurred. This is not considered by the reviewer to affect the relevance of the result.


RANGE-FINDING/SCREENING STUDIES: No information


COMPARISON WITH HISTORICAL CONTROL DATA: Historical control data not presented in study report

Remarks on result:

other: all strains/cell types tested

Any other information on results incl. tables

Table 1a: 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)
0*	16	30	no	325	287	no	14	14	no
0.5	15	26	no	281	262	no	17	17	no
5	14	32	no	226	291	no	14	16	no
100	11	18	no	245	268	no	10	20	no
500	11	28	no	281	233	no	5	14	yes
Positive control	>1000	>1000	no data	>1000	>1000	no data	1000	62	no data

*solvent control withethanol

 

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

	TA1537			TA1538
Conc. (µg/plate)	- MA	+ MA	Cytotoxic (yes/no)	- MA	+ MA	Cytotoxic (yes/no)
0*	11	6	no	4	24	no
0.5	8	4	no	3	24	no
5	12	7	no	1	23	no
100	12	5	no	2	10	yes
500	2	7	yes	4	7	yes
Positive control	44	22	no data	>1000	316	no data

*solvent control with ethanol

Applicant's summary and conclusion

Conclusions:

Trichlorosilane was tested according to a protocol that is similar to OECD 471 and in compliance with GLP. No test substance related increase in the number of reversions was observed when tested to limit concentration in Salmonella typhimurium strains TA98, TA100, TA1535, TA1537 or TA 1538, with and without metabolic activation. Appropriate solvent and positive controls were included and gave expected results. The substance is considered to be non-mutagenic under the conditions of the test.