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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:
experimental study
Adequacy of study:
key study
Study period:
1989-05-19 to 1989-07-06
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it followed a protocol comparable to OECD Guideline 471 but was modified to test the vapor phase of the test substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
The method was modified to use the dessicator methodology in order to test the mutagenicity of the vapor phase of the test substance.
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, other: TA 1535, TA 1537, TA 1538, TA 98, TA 100
Metabolic activation:
with and without
Metabolic activation system:
S9 from aroclor induced rat liver
Test concentrations with justification for top dose:
0, 600, 1000, 3000, 6000, 9000 ppm
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
other: no solvent used
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene, 2-nitrofluorene, sodium azide, 9-aminoacridine, 1,1-dichloroethene
Details on test system and experimental conditions:
METHOD OF APPLICATION: Prepared plates were placed uncovered and inverted in 9l dessicators. An appropriate amount of test substance was placed in a glass petri dish was suspended at the bottom of the dessicator. A magnetic stirring bar was placed at the bottom of the dessicator, and served as a fan to ensure even distribution of the vapor.


DURATION
- Preincubation period: 48 hrs
- Exposure duration: 7-8 hrs at 37 degree C
- Expression time (cells in growth medium): There was an additional incubation time of 40 hrs after exposure.

NUMBER OF REPLICATIONS: 3


Evaluation criteria:
To be considered positive for mutation, at least a doubling of mean revertants per plate in at least one tester strain must be seen. This increase must be dose-related.
Statistics:
Mean number of revertant per plate and the standard deviation was calculated.

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA 1535, TA 1537, TA 1538, TA 98, TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not examined
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
No positive responses were observed in any of the tester strains. The positive control substance, 2-aminoanthracene, did not produce any mutations in strain TA 1538 in one experiment in the presence of S9. As revertants were seen in the test of TA 1538 without S9, and revertants were seen in other strains exposed to positive controls with S9, the lack of revertants was most likely due to a technical error and the study is still considered valid.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Average Revertants per Plate (SD) - Experiment B1

Dose (ppm)

TA 98

TA 100

TA 1535

TA 1537

TA 1538

Without S9

0.0

17 ± 1

105 ± 12

11 ± 1

7 ± 1

8

600

20 ± 5

113 ±  9

13 ± 4

6 ± 1

6

1000

16 ± 3

121 ± 8

14 ± 2

7 ± 1

6

3000

18 ± 4

112 ± 13

17 ± 3

5 ± 4

4

6000

24 ± 4

117 ± 14

12 ± 4

6 ± 4

8

9000

17 ± 3

112 ± 7

14 ± 5

9 ± 2

5

Positive control

227 ± 8

422 ± 44

349 ± 36

481 ± 135

452

With S9

0.0

24 ± 5

119 ± 10

17 ± 1

7 ± 0

12

600

30 ± 10

137 ± 12

23 ± 4

9 ± 4

15

1000

23 ± 5

126 ± 3

14 ± 2

11 ± 5

13

3000

22 ± 1

120 ± 19

16 ± 2

9 ± 2

9

6000

24 ± 2

103 ± 11

14 ± 4

7 ± 2

11

9000

30 ± 6

120 ± 3

17 ± 1

8 ± 2

14

Positive control

3142 ± 139

3902 ± 68

189±  22

351 ± 26

--

Positive vapor control

372 ± 52

Average Revertants per Plate (SD) - Experiment B2

Dose (ppm)

TA 98

TA 100

TA 1535

TA 1537

TA 1538

Without S9

0.0

12 ± 2

107 ± 11

9 ± 5

5 ± 1

19

600

20 ± 1

103 ±  9

8 ± 4

7 ± 3

19

1000

14 ± 4

110 ± 6

12 ± 5

7 ± 2

19

3000

14 ± 1

124 ± 14

12 ± 2

7 ± 2

19

6000

22 ± 6

125 ± 14

15 ± 1

5 ± 2

16

9000

15 ± 6

114 ± 5

13 ± 3

5 ± 3

13

Positive control

444 ± 86

991 ± 67

758 ± 19

162 ± 51

754

With S9

0.0

21 ± 4

132 ± 16

17 ± 4

7 ± 3

26

600

25 ± 7

133 ± 8

18 ± 2

6 ± 1

25

1000

22 ± 2

155 ± 4

15 ± 7

8 ± 3

25

3000

20 ± 1

123 ± 23

16 ± 7

7 ± 3

24

6000

21 ± 4

151 ± 14

15 ± 1

6 ± 2

30

9000

25 ± 4

161 ± 8

11 ± 4

6 ± 1

27

Positive control

2187 ± 166

2229 ± 223

166 ±  32

230 ± 24

2195

Positive vapor control

394 ± 50

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The test substance is not mutagenic.
Executive summary:

This study examined the mutagenicity of vapors of the test substance commercial hexane. Plates of S. typhimurium were exposed for 7 -8 hrs to test atmospheres of 0, 600, 1000, 3000, 6000, or 9000 ppm of test substance. 20,000 ppm of 1,1 -dichloroethene was used a vapor-phase positive control substance. The test substance did not produce a positive response in any of the test strains. The test substance is not mutagenic.