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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
Study period:
25.08.2011 - 15.09.2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report Date:
2011

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Version / remarks:
Kanpoan No.287
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Metabolic activation system:
Phenobarbitol/beta-naphthoflavone induced rat liver S9
Test concentrations with justification for top dose:
3, 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Acetone
- Justification for choice of solvent/vehicle: the solvent was requested by the sponsor.
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
Acetone
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 1535, TA100 without metabolic activation 10 µg/plate
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
Acetone
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylene-diamine 10 µg/plate TA98 and 50 µg/plate TA1537
Remarks:
TA1537, TA98 without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
Acetone
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
WP2 uvrA without metabolic activation 3 µl/plate
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
Acetone
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene 2.5 µg/plate TA1535, TA1537, TA98, TA100 and 10 µg/plate WP2 uvrA
Remarks:
TA1535, TA1537, TA98, TA100, WP2 uvrA with metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

ACTIVATION: S9 mix contained glucose-6-phosphate and NADP as co-factors. The amount of S9 supernatant was 10% v/v in the S9 mix. 0.5 ml S9 was added to test solution, bacterial suspension and top agar giving a final concentration in the cultures of approximately 2% S9.

DURATION
- Preincubation period: 60 minutes at 37C
- Exposure duration: 72 hours

SELECTION AGENT (mutation assays): histidine deficient agar

NUMBER OF REPLICATIONS: triplicate plates, pre-experiment for toxicity and experiment 1 used plate incorporation, the test was repeated using pre-incubation.

DETERMINATION OF CYTOTOXICITY
- Method: other: condition of background lawn


Evaluation criteria:
A test item is considered as a mutagen if a biologically relevant increase in the mean number of revertant colonies exceeding the threshold of twice (strains TA98, TA100 and WP2 uvrA) or thrice (strains TA1535 and TA1537) the mean colony count of the corresponding solvent control is observed. A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration. An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment.
Statistics:
No statistical evaluation of the data was required.

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS

- Precipitation: No precipitation was observed


ADDITIONAL INFORMATION ON CYTOTOXICITY: Cytotoxicity was not evident at any concentrations

Any other information on results incl. tables

Table 1: Experiment 1 - Mean revertant colony counts

 

TA 1535

TA 1537

TA 98

TA 100

WP2 uvrA

Concentration (µg/plate)

-S9

+S9

-S9

+S9

-S9

+S9

-S9

+S9

-S9

+S9

Solvent control

14

21

15

25

33

38

126

130

47

49

Negative control

16

17

17

21

37

54

120

127

44

49

3

12

21

16

24

32

41

123

120

52

49

10

13

18

14

24

34

37

117

131

40

56

33

15

21

18

21

36

37

129

105

44

49

100

13

24

16

24

39

39

139

131

40

53

333

15

18

18

19

38

29

134

134

47

48

1000

14

16

16

15

38

23

142

135

51

46

2500

18

17

18

16

38

23

127

124

45

44

5000

14

18

17

15

29

18

129

119

39

31

Positive control

1536

313

71

388

326

1266

1791

2270

956

227

 

  Table 2: Experiment 2 Mean revertant colony counts 

 

 

TA 1535

TA 1537

TA 98

TA 100

WP2 uvrA

Concentration (µg/plate)

-S9

+S9

-S9

+S9

-S9

+S9

-S9

+S9

-S9

+S9

Solvent control

16

21

22

26

37

37

132

139

49

63

Negative control

18

16

24

28

41

45

142

143

52

64

3

NA

19

NA

26

NA

41

NA

159

NA

58

10

NA

21

NA

24

NA

39

NA

162

NA

55

33

18

24

21

26

31

44

124

124

50

61

100

16

21

24

30

33

40

140

161

58

53

333

17

18

24

19

37

35

134

150

51

53

1000

17

15

21

19

33

29

155

145

58

58

2500

15

16

20

17

30

31

156

127

56

37

5000

17

16

24

16

38

29

155

114

57

42

Positive control

1780

318

118

266

329

1655

1782

1602

643

261

Applicant's summary and conclusion

Conclusions:
3,3-Bis[(dimethylvinylsilyl)oxy]-1,1,5,5-tetramethyl-1,5-divinyltrisiloxane has been tested for mutagenicity to bacteria, in a study which was conducted according to OECD Test Guideline 471 and in compliance with GLP. No evidence of a test substance related increase in the number of revertant colonies was observed with or without metabolic activation in the pre-experiment for toxicity or the initial assay using the plate incorporation method using S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2. The result was confirmed the repeat preincubation experiment. Appropriate positive, negative and solvent controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.