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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:
2003-12-10 to 2004-01-09
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Only three strains are tested. However, an expert statement is added in the field "any other remarks" to justify the fact that no further testing is necessary.

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:
only 3 strains of bacteria used, limited methodology
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 (as cited in study report): T001624
- Physical state: solid
- Appearance: white powder
- CAS: 132961-05-8
- Molecular formula: C23H28F2N4O2
- Molecular weight: 430.5 g/mol
Specific details on test material used for the study:
Name of test material: T 1624, ((Z)-3-[2-[4-[(2,4-difluorophenyl)(hydroxyimino)methyl]-1-piperidinyl]ethyl]-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one)
- Physical state: white powder
- Analytical purity: ~100%
- Storage condition of test material: room temperature in the dark
- Other: date received: 2003-12-01

Method

Target gene:
histidine locus
Species / strain
Species / strain / cell type:
S. typhimurium, other: TA98, TA 100, and TA 102
Details on mammalian cell type (if applicable):
not applicable
Additional strain / cell type characteristics:
other:
Metabolic activation:
with and without
Metabolic activation system:
rat liver homogenate metabolising system (10% liver S9 in standard co-factors)
Test concentrations with justification for top dose:
0.5, 1.5, 5, 15, 50, 150, 500, 1500, 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: no data
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: N-ethyl-N'-nitro-N-nitrosoguanidine at 3 µg/plate on TA100
Remarks:
without S9
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: mitomycin C at 0.5 µg/plate for TA102
Remarks:
without S9
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-Nitroquinoline-1-oxide at 0.2 µg/plate on TA98
Remarks:
without S9
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene at 1 µg/plate for TA100
Remarks:
with S9
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 1,8-dihydroxyanthraquinone at 10 µg/plate for TA 102
Remarks:
with S9
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: benzo(a)pyrene at 5 µg/plate on TA98
Remarks:
with S9
Details on test system and experimental conditions:
METHOD OF APPLICATION: plate incorporation method

Measured aliquots (0.1 mL) of one of the bacterial cultures were dispensed into sets of test tubes followed by 2.0 mL of molten, trace histidine supplemented, top agar, 0.1 mL of the test material formulation, vehicle or positive control and either 0.5 mL of S9-mix or phosphate buffer. The contents of each test tube were mixed and equally distributed onto the surface of Vogel-Bonner Minimal agar plates (one tube per plate).

DURATION
- Exposure duration: 3 days
SELECTION AGENT: histidine

NUMBER OF REPLICATIONS: triplicate

DETERMINATION OF CYTOTOXICITY
- Method: growth of the bacterial background lawn
Evaluation criteria:
no data
Statistics:
no data

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA 98, TA 100, and TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
Precipitation: No test material 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 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.
The S9-mix used in both experiments was shown to be sterile. Results for the negative controls (spontaneous mutation rates) were considered to be acceptable. These data are for concurrent untreated control plates performed on the same day as the Mutation Test.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
The test material caused no visible reduction in the growth of the bacterial background lawn at any dose level.

Remarks on result:
other: all strains/cell types tested

Applicant's summary and conclusion

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

The test material was considered to be non-mutagenic under the conditions of this test.