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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:
no data
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: NTP study carried out to national standards that applied at the time.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
EPA OPPTS 870.5375 - In vitro Mammalian Chromosome Aberration Test
Deviations:
yes
Remarks:
Only one culture per dose; two independent cultures per dose are recommended
GLP compliance:
not specified
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): butyl benzyl phthalate
- Physical state: solid
- Analytical purity: no data
- Impurities (identity and concentrations): no data
- Purity test date: no data
- Lot/batch No.: no data
- Expiration date of the lot/batch: no data
- Stability under test conditions: no data
- Storage condition of test material: no data

Method

Target gene:
not applicable
Species / strain
Species / strain:
Chinese hamster Ovary (CHO)
Details on mammalian cell lines (if applicable):
- Type and identity of media: McCoy's 5a medium supplemented with 10% fetal calf serum, L-glutamine and antibiotics
- Properly maintained: no data
- Periodically checked for Mycoplasma contamination: no data
- Periodically checked for karyotype stability: no data
- Periodically "cleansed" against high spontaneous background: no data
Additional strain characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9 fraction prepared from Aroclor 1254-induced rat liver
Test concentrations with justification for top dose:
0, 125, 400 or 1250 ug/mL
Vehicle:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: included in list of recommended solvents
Controlsopen allclose all
Negative controls:
no
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
triethylenemelamine
Remarks:
Migrated to IUCLID6: 0.15 ug/mL without S9
Negative controls:
no
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
Migrated to IUCLID6: 15.0 ug/mL with S9
Details on test system and conditions:
METHOD OF APPLICATION: in medium


DURATION
- Exposure duration: Without S9 the cells were incubated with the test substance for 12 hours, then colcemid added and incubated for a further 2 hr. With S9 the cells were exposed to the test substance for 2 hr, then incubated for a further 12 hr in fresh medium. Colcemid was added for the final 2 hr of incubation

- Fixation time (start of exposure up to fixation or harvest of cells): 14 hr


SPINDLE INHIBITOR (cytogenetic assays): colcemid

STAIN (for cytogenetic assays): Giemsa


NUMBER OF REPLICATIONS: one


NUMBER OF CELLS EVALUATED: 100 cells/dose


DETERMINATION OF CYTOTOXICITY
- Method: other: doses based on the cytotoxicity seen in a sister chromatid exchange assay in the same cell type.


OTHER EXAMINATIONS:
- Determination of polyploidy: no
- Determination of endoreplication: yes
Evaluation criteria:
Only cells containing 21 +/- 2 chromosomes were scored; all types of aberrations were included. Gaps and endoreduplications were recorded but not included in the totals.
Statistics:
Linear regression analysis of the percentage of cells with aberrations versus the log-dose of the dose was used to test for trend.

Results and discussion

Test results
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
not specified
Vehicle controls valid:
yes
Negative controls valid:
not applicable
Positive controls valid:
yes
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
no data


RANGE-FINDING/SCREENING STUDIES: based on a previous assay for sister chromatid exchanges using the same cell type


Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Butyl benzyl phthalate did not induce chromosome aberrations when tested in an in vitro assay with Chinese hamster ovary cells, both in the presence and absence of a rat liver metabolic activation fraction.
Executive summary:

Butyl benzyl phthalate was assessed for its ability to induce chromosome aberrations in Chinese hamster ovary cells.

Cells were incubated with concentrations of the test substance of up to 1250 ug/mL for 2 hr with S9, or 14 hr without S9. Cells that had been exposed with S9 were placed in fresh medium and incubated for a further 12 hr.; colcemid was added as a spindle inhibitor to all cultures 2 hr before harvesting the cells.After fixation and staining, 100 first-division metaphases per dose were scored for all types of chromosome aberrations.

The test substance did not increase the frequency of aberrations, compared to the vehicle controls.

Butyl benzyl phthalate did not induce chromosome aberrations in an in vitro assay with Chinese hamster ovary cells, either in the presence or absence of a rat liver metabolic activation fraction.