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Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information
Three studies perfomed to examine genetic toxicity of the substance, one for mutergenic proterties towards bacterias, one for clastgenic activity in human lymphocytes and one gene mutation assay in mammalian cells(HPRT).
Link to relevant study records
Reference
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:
2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.10 (Mutagenicity - In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of assay:
in vitro mammalian chromosome aberration test
Species / strain / cell type:
mammalian cell line, other: human peripheral lymphocytes
Details on mammalian cell type (if applicable):
Human peripheral blood was obtained by venipuncture from healthy donors known to be without any medication and collected in heparinised vessels. Small innocula of whole blood (0.5 mL) were added to tubes containing 5 mL of complete culture medium. The tubes were sealed and incubated at 37°C with occasional shaking to prevent clumping.
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
Post-mitochondrial fraction (S9 fraction) from rats treated with Aroclor 1254 was prepared according to MARON and AMES (1983). S9 was collected from 20 - 30 rats. The pooled fraction was tested for:
Test concentrations with justification for top dose:
10, 26, 103, 257, 1029 and 2571 µg IPETC per mL medium
Vehicle / solvent:
dimethyl sulfoxide (DMSO)
Untreated negative controls:
yes
Remarks:
DMSO
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
mitomycin C
Remarks:
was used as the positive control for the study in the absence of metabolic activation.
Untreated negative controls:
yes
Remarks:
DMSO
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
was used as the positive control for the study in the presence of metabolic activation.
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION

- Exposure duration: 4 hours in experiment 1 and 24 hours in experiment 2

SPINDLE INHIBITOR (cytogenetic assays): colcemid® to accumulate cells in a metaphase-like stage of mitosis (c-metaphase).

Evaluation criteria:
The test item is judged to have mutagenic properties with respect to chromosomal or chromatid change, if the following criteria are fulfilled:
o the number of chromosomal aberrations is significantly (at p  0.05) increased compared with the solvent control
o the increase observed is concentration-dependent
o both duplicate cultures lead to similar results
o the increase should not occur in the severely cytotoxic range (mitotic index <0.25), as it is known that high cytotoxicity causes artefacts in the form of aberrations in in vitro chromosomal aberration tests
o a reproducible increase in the number of cells with chromosomal aberrations.

Statistics:
The assessment was carried out by a comparison of the number of chromosome aberrations of the samples with those of the solvent control, using the exact test of R. A. FISHER (p  0.05) as recommended by the UKEMS guidelines (The United Kingdom Branch of the European Environmental Mutagen Society: Report of the UKEMS subcommittee on guidelines for mutagenicity testing, part III, Statistical evaluation of mutagenicity test data, 1989).
Key result
Species / strain:
mammalian cell line, other: human peripheral lymphocytes
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
cytotoxicity was noted in the experiment without and with metabolic activation (24-h or 4-h exposure, respectively) starting at 1029 µg IPETC /mL. Haemolysis was noted at concentrations of 2571 and 5143 µg/mL in both experiments.
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: strain/cell type: human peripheral lymphocytes
Remarks:
Migrated from field 'Test system'.
Conclusions:
Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

Under the present test conditions, IPETC, tested up to cytotoxic concentrations, in the absence and in the presence of metabolic activation employing two exposure times (without S9) and one exposure time (with S9) revealed no indications of mutagenic properties with respect to chromosomal or chromatid damage.
In the same test, Mitomycin C and cyclophosphamide induced significant damages, which confirmed the validity of this assay.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

No positive results in any of the three performed scientific valid genetic toxicity tests leads to the conclusion that the substance is proberbly not mutagenic/genotoxic.


Justification for selection of genetic toxicity endpoint
Study of most relavance to human exposure

Justification for classification or non-classification

No mutergenic/clastogenic properties found for the substance.

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