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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP guideline study with acceptable restrictions. Although 5 strains were tested no strain for detection of cross-linking or oxidising mutagens was included, but in accordance with guideline at time of testing.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1986
Report Date:
1986

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
Strain for detection of oxidising or cross-linking mutagens is missing, but in accordance with guideline at the time of testing.
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: solid, not further specified

Method

Target gene:
His-operon
Species / strain
Species / strain / cell type:
other: TA 1535, TA 1537, TA 1538, TA 98, TA 100
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254-induced rat liver S-9 mix
Test concentrations with justification for top dose:
100, 333, 1000, 3330, 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Very low water solubility of test substance in common solvents. Appropriate solvents not suitable for bacterial culture; therefore, suspension of test substance in DMSO added to cultures.
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 1535 without S-9 mix

Migrated to IUCLID6: 1 µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
TA 100 without S-9 mix

Migrated to IUCLID6: 0.5 µL/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylene-diamine (4 NPD), 10 µg/plate
Remarks:
TA 98 and TA 1538 without S-9 mix
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
TA 1537 without S-9 mix

Migrated to IUCLID6: 60 µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (2AA), 0.5 µg/plate
Remarks:
All strains with S-9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS: triplicates

DETERMINATION OF CYTOTOXICITY
- Method: reduction of background growth
Evaluation criteria:
Acceptability of Assay:
1) Negative control data (number of spontaneous revertants per plate) should reasonably fall within the laboratory background historical range for each tester strain.
2) The positive control chemicals should produce responses in all tester strains which also reasonably fall within the laboratory historical range documented for each positive control substance.
3) The selected dose range should include a clearly toxic concentration as demonstrated by a preliminary toxicity range-finding test with strain TA 100.
Statistics:
Mean and standard deviation of revertant numbers.

Results and discussion

Test results
Species / strain:
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 nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No precipitation occurred up to limit concentrations.

RANGE-FINDING/SCREENING STUDIES:
Eleven serial dilutions of the test substance (0.1, 0.3, 1.0, 3.3, 10.0, 33.3, 100, 333, 1000, 3330, 5000 µg/plate) were plated with a diluted TA 100 culture on non-selective agar for viability counting. For viability counting equal numbers of bacterial cells were plated in the presence of test substance. The percentage of survival of an appropriately diluted TA 100 culture on non-selective agar was determined by comparing the number of colonies on the solvent control plate with those on the test substance plates. Even at the highest test substance concentration used (5000 µg/plate) there was no reduction in survival of TA 100. Therefore, the test substance was tested up to a concentration of 5000 µg/plate in the main test, which is the maximum test concentration to be used according to the OECD guideline.

COMPARISON WITH HISTORICAL CONTROL DATA:
The observed numbers of revertants are well within the ranges of the historical controls.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Maximum mean numbers of revertants (± SD):

Strain

-S9

+S9

Control

Test substance (µg/plate)

Control

Test substance (µg/plate)

TA 1535

9 ± 2

9 ± 1 (100)

12 ± 4

14 ± 2 (333)

TA 1537

12 ± 4

14 ± 3 (1000)

9 ± 2

20 ± 19 (5000)

TA 1538

14 ± 2

19 ± 6 (100)

26 ± 6

28 ± 3 (100)

TA 98

36 ± 10

38 ± 9 (333)

30 ± 14

36 ± 8 (333)

TA 100

121 ± 6

119 ± 7 (5000)

98 ± 19

138 ± 9 (5000)

 

The test substance did not induce a statistically significant dose-related increase in the numbers of revertants in any of the tester strains.

Conclusion:

The test substance does not have to be considered as mutagenic to bacteria.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative