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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:
1996-01-31 to 1996-02-23
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
The restrictions were that the range of strains does not comply with the current guideline and only 2-aminoanthracene was used as positive control in the presence of S9.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
1983
Deviations:
yes
Remarks:
only 2-aminoanthracene as +S9 control and no TA 102 or E.coli strains used.
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
his Operon
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
other: rfa, uvrB (TA 98 and 100: pKM101)
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:
50 - 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO

- Justification for choice of solvent/vehicle: It is assumed by the reviewer that the solvent was chosen for its solubility properties and relative non-toxicity to bacteria.
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
Remarks:
+ S9: All strains: 2.5 µg/plate in DMSO
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
-S9: TA 98: 2.5 µg/plate in DMSO
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
-S9: TA 100 and TA 1535: 5.0 and 2.5 µg/plate in aqua bidest, respectively.
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
- S9: TA 1537: 25 µg/plate in DMSO
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION
- Preincubation period: 30 minutes
- Expression time (cells in growth medium): 72 hours

NUMBER OF REPLICATIONS: 3 Plates per test concentration

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth, background lawn assessment

METABOLIC ACTIVATION SYSTEM: S9 mix was prepared freshly before use. One part of S9 fraction was mixed with 9 parts of a cofactor solution resulting in the following mixture:
-10% S9 fraction
- 33 mM KCl
- 8 mM MgCl2
- 5 mM glucose-6-phosphate
- 4 mM NADP, 100 mM Na2HPO4/NaH2PO4, pH 7.4.
Evaluation criteria:
For a test substance to be considered positive, it must cause at least a doubling in the mean revertants per plate of at least one tester strain with a minimum of two increasing concentrations of test article.
The increase must be accompanied by a dose response towards increasing concentrations of the test article.

Results and discussion

Test results
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:
cytotoxicity
Remarks:
5000 μg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid

Any other information on results incl. tables

Table 2: Experiment 1 Plate incorporation assay - 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*

21

42

No

91

109

No

8

11

No

50

24

46

No

141

121

No

16

11

No

160

20

45

No

134

131

No

8

10

No

500

25

36

No

113

134

No

7

16

No

1600

25

39

No

130

135

No

9

11

No

5000

30

31

No

137

115

No

9

15

No

Positive Control

142

1324

No

544

1474

No

322

195

No

*solvent control with DMSO

Table 2: Experiment 1 Plate incorporation assay - Number of revertants per plate (mean of 3 plates)

 

TA1537

Conc.
µg/plate

— MA

+ MA

Cytotoxic
(yes/no)

0*

2

23.4

No

50

6

14

No

160

8

16

No

500

9

9

No

1600

6

13

No

5000

2

16

No

Positive Control

3

152

No

*solvent control with DMSO

Table 3: Experiment 2 Pre incubation assay - 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*

23

35

No

147

119

No

9

11

No

50

19

38

No

108

111

No

6

13

No

160

20

29

No

110

137

No

6

13

No

500

18

25

No

104

137

No

6

11

No

1600

21

32

No

123

148

No

6

13

No

5000

6

12

Yes

48

76

Yes

0

1

Yes

Positive Control

110

1264

No

527

1466

No

306

220

No

*solvent control with DMSO

Table 3: Experiment 2 Pre incubation assay Number of revertants per plate (mean of 3 plates)

 

TA1537

Conc.
µg/plate

— MA

+ MA

Cytotoxic
(yes/no)

0*

5

15

No

50

6

10

No

160

5

11

No

500

5

9

No

1600

3

12

No

5000

0

5

Yes

Positive Control

100

164

No

*solvent control with DMSO

Applicant's summary and conclusion

Conclusions:
Tripotassium propylsilanetriolate has been tested in a bacterial mutagenicity assay according to OECD 471 and in compliance with GLP No mutagenic effect was observed for the test substance tested up to cytotoxic concentration in any of the test strains in two independent experiments without and with metabolic activation. Appropriate positive 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.