4-methyl-4-phenylpentan-2-ol

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Negative results were produced in three in vitro studies -Ames test, mouse lymphoma assay and in a chromosome aberration test in human lymphocytes.

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in accordance with standard test guidelines (OECD TG 473) and is GLP compliant.

Qualifier:

according to guideline

Guideline:

OECD Guideline 473 (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:

other: human lymphocytes

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbital/ß-naphthoflavone induced rat liver S9-mix

Test concentrations with justification for top dose:

Experiment I - 11.6 to 1780 ug/mL (10 dose levels)
Experiment II - without S9 mix 3.8 to 581.2 ug/mL (10 dose levels); with S9 mix 62.0 to 1780 ug/mL (7 dose levels)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO (purity 99.5%)

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

cyclophosphamide

ethylmethanesulphonate

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: 50-80 hours
- Exposure duration: Experiment I, 4 or 22 hours without S9 ; 22 hours with S9. Experiment II, 46 hours without S9 ; 4 hours with S9 mix
- Expression time (cells in growth medium): 22 or 46 hours
- Selection time (if incubation with a selection agent):
- Fixation time (start of exposure up to fixation or harvest of cells): 19 or 43 hours

SPINDLE INHIBITOR (cytogenetic assays): colchicine

STAIN (for cytogenetic assays): Giesma staining or Fluorescent plus Giesma staining for each duplicate

NUMBER OF REPLICATIONS: Two

NUMBER OF CELLS EVALUATED:at least 1000 per culture

DETERMINATION OF CYTOTOXICITY
- Method: reduced mitotic index

OTHER EXAMINATIONS:
- Analysis of metaphase cells for breaks, fragments ,deletions, exchanges and chromosomal disintegrations

Evaluation criteria:

Test item is classed as mutagenic if the number of indiced aberrations is outside the historical control range of 0.0 -0.4% AND a concentration related or significant increase of the number of structural abnormalities is observed.

Test item is anuegenic if the number of induced aberrations (polyploidy and endoreduplication) is outside the range of historical contol data (0.0 to 0.8% polyploidal cells).

Statistics:

Fischers exact test (p<0.05)

Species / strain:

lymphocytes: human

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 189.8 ug/mL and above

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: no increase in pH value was noted : control =7.0, high dose of 1780 ug/mL =7.1
- Effects of osmolality: no increase in osmolality was noted : control =395mOsm; high dose of 1780 ug/mL =394 mOsm
- Precipitation: evident at doses of 581.2 ug/mL and above
- Other confounding effects:

RANGE-FINDING/SCREENING STUDIES: Yes at 10 dose levels to determine cytoxicity.,

COMPARISON WITH HISTORICAL CONTROL DATA: used to determine mutagenicity/non mutagenicty and polyploidy.

Remarks on result:

other: other:

Remarks:

Migrated from field 'Test system'.

In Experiment I and Experiment II in the absence and presence of S9 mix, no biologically relevant increase in the number of cells carrying structural chromosome aberrations was observed.

The aberration rates of cells after treatment (0 to 4.0% aberrant cells excluding gaps) were within the range of the laboratory's control data. However in experiment II after continuous treatment without S9 mix the aberration rate of 4.0% achieved statistical significance but was not considered to be biologically significant as this value fell within the laboratory's historical control data.

In both experiments, there was no biologically relevant increase in the rate of polyploid metaphases (0 to 0.4%) as compared to controls (0 to 0.2%).

Conclusions:

Interpretation of results (migrated information):
negative

Under the test conditions, 4-methyl-4-phenylpentan-2-ol did not induce structural chromosomal aberrations in human lymphocytes in vitro in the presence and absence of metabolic activation.

Executive summary:

The test item, 4-Methyl-4-phenylpentan-2-ol, was assessed for its potential to induce chromosomal aberrations in human lymphocytes in the presence and absence of metabolic activation by S9 mix. In a study conducted in accordance with OECD test guideline 473, two experiments were performed . In Experiment I the exposure periods were 4 hours with and without S9 mix and 22 hours without S9 mix. Chromosomes were prepared 22 hours after start of exposure. In Experiment II - exposure periods were 4 hours with S9 mix and 46 hours without S9 mix. Chromosomes were prepared 46 hours after start of exposure. Doses were as follows - Experiment I - 11.6 to 1780 ug/mL (10 dose levels) ; Experiment II - without S9 mix 3.8 to 581.2 ug/mL (10 dose levels); with S9 mix 62.0 to 1780 ug/mL (7 dose levels). In each experiment two parallel cultures were analysed. 100 metaphase plates per culture were scored for structural chromosomal aberrations.- at least 1000 cells per culture were counted for determination of mitotic index.

In both Experiment I and Experiment II in the absence and presence of S9 mix, no biologically relevant increase in the number of cells carrying structural chromosome aberrations was observed. The aberration rates of cells after treatment (0 to 4.0% aberrant cells excluding gaps) were within the range of the laboratory's control data. However in experiment II after continuous treatment without S9 mix the aberration rate of 4.0% achieved statistical significance but was not considered to be biologically relevant as this value fell within the laboratory's historical control data.

Under the test conditions, 4-methyl-4-phenylpentan-2-ol did not induce structural chromosomal aberrations in human lymphocytes in vitro in the presence and absence of metabolic activation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

Justification for selection of genetic toxicity endpoint
Three key in vitro genetic toxicity studies have been conducted with 4-methyl-4-phenylpentan-2-ol. The two in vitro mutagenicty studies, one in bacterial cells and one in mammalian cells, were both negative and the cytogenicity study in human lymphocytes was also negative. It is the study in human cells which has been selected as the key study for this endpoint summary.

Justification for classification or non-classification

Negative results were produced in an in vitro cytogenicity study in mammalian cells, in a gene mutation study in mammalian cells and also in a gene mutation study in bacterial cells. Therefore, no classification is required for this endpoint.