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Genetic toxicity: in vitro

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in vitro cytogenicity / chromosome aberration study in mammalian cells
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Meets the criteria for classification as Reliable without restriction according to Klimisch et al (1997)

Data source

Reference Type:
study report

Materials and methods

Test guideline
according to
EU Method B.10 (Mutagenicity - In Vitro Mammalian Chromosome Aberration Test)
GLP compliance:
yes (incl. certificate)
Type of assay:
in vitro mammalian chromosome aberration test

Test material



Species / strain
Species / strain / cell type:
mammalian cell line, other: human lymphocytes
Details on mammalian cell type (if applicable):
For each experiment, sufficient whole blood was drawn from the peripheral circulation of a volunteer who had been previously screened for suitability. The volunteer had not been exposedto high levels of radiation or hazardous chemicals and had not knowingly recently suffered from a
viral infection. The cell-cycle time for the lymphocytes from the donors used in this study was determined using BrdU (bromodeoxyuridine) incorporation to assess the number of first, second and third division metaphase cells and so calculate the average generation time (AGT). The average AGT for the regular donors used in this laboratory has been determined to be approximately 17 hours under typical experimental exposure conditions.
Metabolic activation:
with and without
Metabolic activation system:
Phenobaritone and Beta-naphtholflavone induced rat liver S9.
Test concentrations with justification for top dose:
Concentration range in the main test (with and without metabolic activation) = 625 to 5000 µg/ml
Vehicle / solvent:
Minimal Essential Medium (MEM)
Untreated negative controls:
Negative solvent / vehicle controls:
culture medium
True negative controls:
Positive controls:
Positive control substance:
other: in the absence of S9 mitomycin C. In the presence of S9 cyclophosphamide
Details on test system and experimental conditions:
Exposure period (with metabolic activation): 4 hours
Exposure period (without metabolic activation): 4 hours

Fixation time:
24 hours, with and without metabolic activation.
Evaluation criteria:
Where possible the first 100 consecutive well-spread metaphases from each culture were counted, where there was approximately 50% of cells with aberrations, slide evaluation was terminated at 50 cells. If the cell had 44-48 chromosomes, any gaps, breaks or rearrangements were noted according to the simplified system of Savage (1976) recommended in the 1983 UKEMS guidelines for mutagenicity testing (Appendix 1).
The frequency of cells with aberrations excluding gaps and the frequency of polyploid cells was compared, where necessary, withthe concurrent vehicle control value using Fisher's Exact test.

Results and discussion

Test results
Species / strain:
mammalian cell line, other: Human lymphocytes
Metabolic activation:
with and without
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
Untreated negative controls validity:
not applicable
Positive controls validity:
Additional information on results:
All vehicle (solvent) controls had frequencies of cells with aberrations within the range expected for normal human lymphocytes.

All the positive control materials induced statisically significant increases in the frequency of cells with aberrations indicating the satisfactory performance of the test and of the activity of the metabolising system.

The test material was non-toxic and did not induce any statistically significant increases in the frequency of cells with the aberrations, in either of the two separate experiments, using a dose range that was the maximum recommended dose level.
Remarks on result:
other: all strains/cell types tested
Migrated from field 'Test system'.

Any other information on results incl. tables

See Tables 4, 5,6 and 7 in the attached study report for details on number of aberrations per dose group.

Applicant's summary and conclusion

Interpretation of results (migrated information):

The test material was therefore considered to be non-clastogenic to human lymphocytes in vitro .