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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
(1997)
Deviations:
yes
Remarks:
(no strain was included for detection of oxidising or cross-linking substances)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): BRD 1155; 07651 J8 003
- Substance type: alkoxysilane
- Physical state: liquid
- Lot/batch No.: 1
- Storage condition of test material: at 4°C, in the dark under dry conditions

Method

Target gene:
his operon
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 1538
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:
0.05-5 mg/plate
Vehicle / solvent:
- Solvent: ethanol
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: +S9: 2-anthramine (TA 98, TA 100, TA 1535, TA 1537, TA 1538); -S9: 2-nitrofluorene (TA98); methyl methanesulfonate (TA 100); ethyl methanesulfonate (TA 1535); 9-aminoacridine (TA 1537); 2-nitrofluorene (TA 1538)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 h

NUMBER OF REPLICATIONS: 3


DETERMINATION OF CYTOTOXICITY
- Cytotoxicity was determined in a preliminary study using strain TA 98 and also within the main study cytotoxicity was determined. No further information was given about the method applied.


POSITIVE CONTROLS:
+S9: 2-anthramine (TA 98, TA 100, TA 1535, TA 1537, TA 1538: 0.002 mg/plate)
-S9: 2-nitrofluorene (TA98: 0.001 mg/plate); methyl methanesulfonate (TA 100: 0.1 mg/plate); ethyl methanesulfonate (TA 1535: 10 mg/plate); 9-aminoacridine (TA 1537: 0.05 mg/plate); 2-nitrofluorene (TA 1538: 0.001 mg/plate)
Evaluation criteria:
No significant effects: number of colonies after treatment with test substance is less than 2-fold the number of colonies of the solvent control.
Significant effects: number of colonies after treatment with test substance is at least 2-fold the number of colonies of the solvent control.

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
-S9: TA 98, TA 1535 (5 mg/plate), TA 100, TA 1537, TA 1538 (1 and 5 mg/plate); +S9: TA 1537 (5 mg/plate)
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
In a preliminary study the test substance was applied to bacteria (TA 98) from 0.5 to 100 mg/plate. Cytotoxicity was observed from 5 mg/plate upwards.

Any other information on results incl. tables

Table 1: Test results of experiment 1.

With or without S9-Mix

Test substance concentration

Mean number of revertant colonies per plate

(μg/plate)

(average of 3 plates ± Standard deviation)

 

 

 

 

TA 98

TA 100

TA1535

TA1537

TA1538

0

28±4

83±4

9±3

5±1

22±1

50

25±1

91±5

9±4

4±1

26±1

100

26±8

90±11

6±2

5±0

23±4

500

21±5

101±9

7±0

6±2

19±5

1000

21±2

78±6

11±4

8±5

26±4

5000

T

53±8

5±1

T

5±2

Positive controls, –S9

Name

2-NF

MMS

EMS

9-AA

2-NF

Concentrations (μg/plate)

1

100

10000

50

1

Mean No. of colonies/plate (average of 3)

472

299

1035

131

248

+

0

39±4

112±12

13±5

5±2

34±9

+

50

35±5

107±2

8±2

7±4

40±4

+

100

36±5

107±20

8±2

5±2

35±13

+

500

37±1

108±6

12±3

7±2

33±3

+

1000

34±7

102±8

10±3

4

33±8

+

5000

36±3

111±4

9±4

4±2

38±7

Positive controls, +S9

Name

2-A

2-A

2-A

2-A

2-A

Concentrations (μg/plate)

2

2

2

2

2

Mean No. of colonies/plate (average of 3)

554

1528

239

63

298

Table 2: Test results of experiment 2.

With or without S9-Mix

Test substance concentration

Mean number of revertant colonies per plate

(μg/plate)

(average of 3 plates ± Standard deviation)

 

 

 

 

TA 98

TA 100

TA1535

TA1537

TA1538

0

28±5

78±7

7±2

6±2

32±6

50

28±3

81±16

7±3

5±2

32±4

100

29±2

73±17

7±3

4±1

30±3

500

27±6

73±8

7±3

5±1

25±3

1000

28±6

T

5±3

2±1

7±6

5000

T

T

7±1

T

T

Positive controls, –S9

Name

2-NF

MMS

EMS

9-AA

2-NF

Concentrations (μg/plate)

1

100

10000

50

1

Mean No. of colonies/plate (average of 3)

573

270

835

116

548

+

0

43±10

118±4

9±5

6±1

38±3

+

50

41±5

107±13

11±2

5±3

47±11

+

100

43±2

101±14

8±2

5±1

38±10

+

500

44±14

101±11

9±5

5±3

42±9

+

1000

46±11

98±17

9±1

6±2

49±4

+

5000

43±8

109±5

11±2

6±1

41±12

Positive controls, +S9

Name

2-A

2-A

2-A

2-A

2-A

Concentrations (μg/plate)

2

2

2

2

2

Mean No. of colonies/plate (average of 3)

673

1337

185

35

579

 

MMS = methyl methanesulfonate

EMS = ethyl methanesulfonate

9AA = 9-aminoacridine

2-A = 2-anthramine

T = cytotoxic

Applicant's summary and conclusion

Conclusions:
Interpretation of results: negative

In a bacterial mutagenicity assay similar to OECD 471 and GLP, no mutagenic effect was observed for the test substance tested up to the top dose of 5000 µg/plate in any of the test strains in two independent experiments without and with metabolic activation. The test substance is non-mutagenic under the applied conditions.