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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
6 June 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted in GLP compliance and in accordance with several internationally established guidelines (OECD, EEC, EPA guidelines, see below).

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
not specified
Qualifier:
according to guideline
Guideline:
EU Method B.10 (Mutagenicity - In Vitro Mammalian Chromosome Aberration Test)
Deviations:
not specified
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.5375 - In vitro Mammalian Chromosome Aberration Test
Deviations:
not specified
GLP compliance:
yes (incl. QA statement)
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
480-420-2
EC Name:
-
Cas Number:
144702-27-2
Molecular formula:
C33 H29 N5
IUPAC Name:
4'-{[4-methyl-6-(1-methyl-1H-1,3-benzodiazol-2-yl)-2-propyl-1H-1,3-benzodiazol-1-yl]methyl}-[1,1'-biphenyl]-2-carbonitrile
Test material form:
other: solid
Details on test material:
- Name of test material (as cited in study report): BIBR 277 Nitril
- Physical state: Solid
- Analytical purity: 99.7%
- Purity test date: 20 March 2007
- Lot/batch No.: 80A
- Expiration date of the lot/batch: 08 March 2008
- Stability under test conditions: yes
- Storage condition of test material: At room temperature, dark and dry

Method

Target gene:
not specified
Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Details on mammalian cell type (if applicable):
- Type: CHO KI cells
- Properly maintained: yes (kept frozen until use)
- Periodically checked for Mycoplasma contamination: yes
Metabolic activation:
with and without
Metabolic activation system:
S9 mix
Test concentrations with justification for top dose:
Experiment A:
9.76, 19.53, 39.06, 78.13 and 156.25 microg/mL (both with and without S9)

Experiment B:
4.88, 9.76, 19.53 and 39.06 microg/mL (both with and without S9)
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
other: N-Nitrosodimethylamin
Remarks:
ethymmethanesulphonate without S9, N-Nitrosodimethylamin with S9.
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium; in agar (plate incorporation); preincubation; in suspension; as impregnation on paper disk

DURATION
- Preincubation period: 24 hrs
- Exposure duration: A: 3 hrs 8each with and without S9); B: 20 hours (without S9), 3 hours (with S9)
- Expression time (cells in growth medium): A: 20 hours; B: 28 hours
- Fixation time (start of exposure up to fixation or harvest of cells): two hours prior to harvesting

NUMBER OF REPLICATIONS: 2 per concentration

NUMBER OF CELLS EVALUATED: > 200

DETERMINATION OF CYTOTOXICITY
- Method: number iof abberations

OTHER EXAMINATIONS:
- Determination of polyploidy: yes
- Determination of endoreplication:yes
Evaluation criteria:
The following criteria were taken into account:

percentage of cells with structural chromosome abberations;
different types of abberations;
gaps;
increased number of polyploid cells
increased number of endoreduplicated chromosomes

Results and discussion

Test results
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH:
- Effects of osmolality:
- Evaporation from medium:
- Water solubility:
- Precipitation:
- Other confounding effects:

RANGE-FINDING/SCREENING STUDIES:
a range-finding study was performed.

COMPARISON WITH HISTORICAL CONTROL DATA:


ADDITIONAL INFORMATION ON CYTOTOXICITY:
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
BIBR 277 Nitril, tested up to cytotoxic concentrations, both with and without metabolic activation, did not induce structural chromosome abberations in this test in Chinese Hamster Ovary cells.
Therefore, BIBR 277 Nitril is considered not clastogenic in this system.