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Toxicological information

Genetic toxicity: in vitro

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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:
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

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strain
Species / strain:
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:
- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle: none given
Controlsopen allclose all
Negative controls:
no
Solvent 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
Negative controls:
no
Solvent 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
Negative controls:
no
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-anthramine
Remarks:
all strains with activation
Negative controls:
no
Solvent 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 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:
other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
not applicable
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
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


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.