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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:
2003-07-17 to 2003-07-21
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Study performed with methods similar to OECD Guideline 471 (Bacterial Reverse Mutation Assay) with the following deviations: 1) only three tester strains were used and 2) limited details on test substance (purity was lacking) and materials and methods were provided. Since the test is positive, performing an Ames test covering the 5 required strains will not provide any additional information to change the conclusion of the classification.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
1) only three tester strains were used and 2) limited details on test substance (purity was lacking) and materials and methods were provided.
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material: JNJ-1692405-AAC (T002006)
- Appearance: yellow powder
- Physical state: solid
Specific details on test material used for the study:
Description: Pale yellow powder
Batch number: 00282450
Date received: 2003-04-29
Storage condition: Room temperature in the dark

Method

Target gene:
histidine locus
Species / strain
Species / strain:
other: TA 98, TA 100, and TA 102
Additional strain characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
10 % rat liver S9 in standard co-factors
Test concentrations with justification for top dose:
0, 0.5, 1.5, 5, 15, 50, 150, 500, 1500, 5000 µg/plate
Vehicle:
- Vehicle(s)/solvent(s) used: sterile distilled water
- Justification for choice of solvent/vehicle: no data
Controlsopen allclose all
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: N-ethyl-N'-nitro-N-nitrosoguanidine at 3 µg/plate with TA100
Remarks:
without S9
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Mitomycin C at 0.5 µg/plate with TA102
Remarks:
without S9
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-Nitroquinoline-1-oxide at 0.2 µg/plate with TA98
Remarks:
without S9
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene at 1 µg/plate with TA100
Remarks:
with S9
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 1,8-Dihydroxyanthraquinone at 10 µg/plate with TA102
Remarks:
with S9
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Benzo(a)pyrene at 5 µg/plate with TA98
Remarks:
with S9
Details on test system and conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 3 days


NUMBER OF REPLICATIONS: Salmonella typhimurium strains TA98, TA100 and TA102 were treated with suspensions of the test material using the Ames plate incorporation method at nine dose levels, in triplicate, both with and without the addition of a rat liver homogenate metabolising system (10% liver S9 in standard co-factors).


NUMBER OF CELLS EVALUATED: not applicable


DETERMINATION OF CYTOTOXICITY
- Method: reduction in bacterial background lawn

Evaluation criteria:
no data
Statistics:
no data

Results and discussion

Test results
Species / strain:
other: TA 98, TA 100, and TA 102
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity:
yes
Vehicle controls valid:
yes
Negative controls valid:
not applicable
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No test substance precipitate was observed on the plates at any of the doses tested in either the presence or absence of S9 mix.

RANGE-FINDING/SCREENING STUDIES:
- no data

COMPARISON WITH HISTORICAL CONTROL DATA:
The vehicle (sterile distilled water) control plates gave counts of revertant colonies within the normal range. All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with and without metabolic activation. Thus, the sensitivity of the assay and the efficacy of the S9-mix were validated.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- The test substance caused a visible reduction in the growth of the bacterial background in all of the tester strains (except TA102 with S9 mix only), initially at 1500 µg/plate. The test substance was therefore, tested up to the maximum recommended dose level of 5000 µg/plate.

Any other information on results incl. tables

Dose-related and toxicologically significant increases in the frequency of revertant colonies were recorded in bacterial strains TA100 (with and without S9) and the remaining strains in the presence of S9 only at the upper sub-toxic dose levels of the test material. The first evidence of a two-fold increase over the concurrent vehicle control was noted in TA100 at 5 and 150 μg/plate without and with S9 respectively. All of the toxicologically significant increases observed were substantially greater than the concurrent solvent control and the in-house historical maxima.

Applicant's summary and conclusion

Conclusions:
Interpretation of results:
positive with and without metabolic activation

The test substance was evaluated for mutagenic potential in the Ames test using S. typhimurium strains TA98, TA100 and TA102 in the absence and presence of metabolic activation. The test substance was considered to be mutagenic under the conditions of this test.