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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:
1997.11.14-1997.12.09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1998

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
other: OECD draft guidelines 471 and 472 (1995)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver S9
Test concentrations with justification for top dose:
75, 200, 600, 1800 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle: based on sponsor's request and compatibility with the target cells
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene 1.0 µg/plate
Remarks:
TA98, TA100, TA1535, TA1537, WP2 uvrA with metabolic activation
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
TA98 without metabolic activation 1.0 µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA100 and TA1535 without metabolic activation 1.0 µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
TA1537 without metabolic activation 75 µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
WP2 uvrA without metabolic activation 1000 µg/plate
Details on test system and experimental conditions:
METHOD OF APPLICATION: preincubation

ACTIVATION: S9 mix contained glucose-6-phosphate and NADP as co-factors. 0.5 ml of S9 mix containing 10% S9 was added to agar, bacterial suspension and test substance to a total volume of 2.65, giving a final concentration of approximately 1% S9.

DURATION
- Preincubation period: 60 minutes
- Exposure duration: 48 - 72 hours

NUMBER OF REPLICATIONS: triplicate plates, experiment repeated



DETERMINATION OF CYTOTOXICITY
- Method: condition of background lawn
Evaluation criteria:
A result is positive if it causes a dose related increase in the mean revertants per plate of at least one tester strain with a minimum of two increasing concentrations of test article. This would be an increase of at least 3-fold of the solvent control for TA1535 and TA1537 and a 2-fold increase of the solvent control for TA98, TA100 and WP2 uvrA
Statistics:
None available

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:
not applicable
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:
not valid
Positive controls validity:
valid

Any other information on results incl. tables

Table 1 Experiment 1 Revertants per plate - preincubation (mean of 3 plates)

Treatment µg/plate

 TA98

TA 98

 TA100

TA 100

 TA1535

TA 1535

 TA1537

TA 1537

  WP2 uvrA

WP2 uvrA

-S9

  +S9

-S9

= S9

-S9

+S9

-S9

+S9

-S9

+ S9

Solvent control

   19

 37

138

151

   8

  9

  6

 5

 16

 17

75

   20

 30

139

148

 11

 14

  6

 7

 21

 24

200

   23

 38

123

165

 10

 13

  6

 5

 18

 18

600

   21

 37

111

160

 10

 12

  7

 8

 17

 18

1800

   25

 31

132

143

   9

 10

  4

 6

 18

 17

5000

   20

 26

125

133

 11

 12

  5

 6

 13

 14

Positive control

1037

916

605

790

551

112

775

87

437

511

 

Table 2 Experiment 2 Revertants per plate - preincubation (mean of 3 plates)

Treatment µg/plate

 TA98

TA 98

 TA100

TA 100

 TA1535

TA 1535

 TA1537

TA 1537

 WP2 uvrA

WP2 uvrA

-S9

 +S9

-S9

+ S9

-S9

+S9

-S9

+S9

-S9

+ S9

Solvent Control

14

25

119

129

8

13

8

8

18

22

75

15

23

117

134

5

12

6

5

18

22

200

12

18

111

109

7

9

4

6

14

17

600

10

23

112

123

9

9

5

9

12

14

1800

12

23

90

119

7

8

6

8

15

14

5000

12

24

94

119

9

9

3

6

14

10

Positive control

736

975

500

921

457

94

719

87

438

358

Applicant's summary and conclusion

Conclusions:
Triethoxy(octyl)silane has been tested for mutagenicity to bacteria in a study conducted according to OECD TG 471 and in compliance with GLP. No evidence of a substance related increase in the number of revertants was observed with or without activation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2 uvr A in the initial or the repeat experiment, both of which used the preincubation method. Appropriate solvent and positive 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.