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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:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: read across; Guideline study, GLP, 4 strains included

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
S9-mix from Syrian golden Hamster liver
Test concentrations with justification for top dose:
0-1-3,3-10-33,3-100-333-1000-5000 µg/plate
Vehicle / solvent:
water
Controls
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
sodium azide
congo red
other: 4-nitro-o-phenylenediamine
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium; in agar (plate incorporation); preincubation; in suspension; as impregnation on paper disk

DURATION
- Preincubation period: 30 minutes
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: other:evaluation of background lawn
Evaluation criteria:
Validity criteria:
normal background lawn
normal range of spontaneous reversions in control

effect criteria:
reproducible, significant, dose related increase of reversions
Statistics:
none

Results and discussion

Test results
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
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Dose µg/plate

S9-mix

TA1535

TA1535

TA1537

TA1537

TA98

TA98

TA100

TA100

Negative Control

-

9

12

4

7

32

30

105

107

Solvent Control

-

9

12

5

6

34

20

103

113

10

-

8

15

6

5

33

22

113

94

100

-

8

19

4

5

39

29

102

79

333,3

-

10

15

4

8

30

28

109

93

1000

-

8

14

6

10

28

31

112

85

5000

-

10

14

4

11

32

28

98

98

Pos Control

-

945

1080

209

240

2286

2076

973

1170

Negative Control

+

12

14

5

4

31

45

91

93

Solvent Control

+

6

12

5

5

32

43

83

100

10

+

8

15

3

3

25

46

95

97

100

+

8

12

4

3

33

42

86

94

333,3

+

6

12

5

3

36

49

114

120

1000

+

7

14

4

4

25

47

133

132

5000

+

11

16

3

7

20

22

131

129

Pos. Control

+

310

344

389

383

333

489

265

338

Applicant's summary and conclusion

Conclusions:
The test item did not induce gene mutations in 4 strains of Salmonella typhimurim with and without metabolic activation by syrian hamster liver S9.mix.
Executive summary:

A study was performed to investigate the potential of Braun HH 469 to induce gene mutations according to the pre-incubation method for azo-dyes using the salmonella typhimurium strains TA 1535, TA 1537, TA 98 and TA 100. The assay was performed in two independent experiments using identical procedures' both with and without Syrian hamster liver microsomal activation. Each concentration, including the controls, was tested in triplicate. The Test article was tested at the following concentrations: 10.0, 100.0, 333.3, 1000.0, and 5000.0 µg/plate. Toxic effects, evidenced by a reduction in the number of revertants, occurred in strain TA 98 at 5000.0 µg/ptate in the presence of metabolic activation in experiment II.

The plates incubated with the test article showed, normal background growth up to 5000.0 µg/ptate with and without S9 mix in all strains used. Up to the highest investigated dose, neither a significant and reproducible increase of the number of revertants was found in any strain as compared to the solvent control nor a concentration-dependent enhancement of the revertant number exists. The presence of liver microsomal activation did not influence these findings. Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant coronies.

CONCLUSTON: In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test article did not induce point mutations by base pair changes or frameshifts in the genome of the strains used. Therefore, Braun HH 469 is considered to be non-mutagenic in this salmonella tlphimurium reverse mutation assay.