Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECd guideline 471 study conducted under GLP. The study was selected as a key study because the information provided for the hazard is sufficient to evaluate the need for classification and labelling and/or risk assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
Ecoli WP2uvrA was also evaluated in the study (with and without activation)
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254-induced rat liver homogenate (S9-mix).
Test concentrations with justification for top dose:
10, 20, 40, 60, 76% in the atmosphere
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
yes
Remarks:
sham exposed bacteria
Positive controls:
yes
Positive control substance:
2-acetylaminofluorene
Details on test system and experimental conditions:

- Exposure duration: 4 hr 15 minutes to test substance in gas exposure chamber followed by 48-72 hour exposure at 37C
Evaluation criteria:
Study is considered valid if the mean colony counts of the control values of the strains are within acceptable ranges, if the results of the positive controls meet the criteria for a positive response, and if no more than 5 % of the plates are lost through contamination or other unforeseen events.
A test substance is considered to be positive in the bacterial gene mutation test if the mean number of revertant colonies on the test plates is concentration-related increased or if a two-fold or more increase is observed compared to that on the negative control plates.

A test substance is considered to be negative in the bacterial gene mutation test if it produces neither a dose-related increase in the mean number of revertant colonies nor a positive response at any of the test points.
Statistics:
None

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
only in TA100 at 10% and greater
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium, other: TA1535, 1537, and 98
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

The substance caused a dose related increase at and above the 10% dose, and a more than two-fold increase at and above the 20% dose to strains TA100 and WP2uvrA, only in the presence of S9 mix.

The positive control for WP2 in the absence of S9 -mix induced a 2.5 fold increase not the 3 fold increase as required. However, the test substance induced a greater than 3 fold increase in revertants indicating the validity of this test system. The remaining controls all behaved as expected.

Mean Number of Revertants Counted (triplicate samples)

 

TA1535

TA 1537

TA 98

TA 100

WP2uvrA

 

-S9

+ S9

-S9

+S9

-S9

+ S9

-S9

+ S9

-S9

+ S9

0 %

46

33

23

22

39

61

224

146

44

43

10 %

32

32

18

28

45

59

134

197

46

83

20 %

53

33

14

30

43

57

122

318

43

106

40 %

26

40

19

34

52

65

153

317

54

153

60 %

37

47

23

30

35

58

174

383

51

174

76 %

28

50

20

26

53

60

157

372

46

175

Pos Control

552

394

3651

173

807

556

688

1160

133

1218

 

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive with metabolic activation (TA100 and E.coli uvr-a

The test substance was mutagenic under the conditions employed in this study (TA100 and WP-2 in the presence of S9) but was not mutagenic in these strains in the absence of S9 or in any of the other strains with or without metabolic activation.