p-vinylphenol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 January to 20 February 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 490 (In Vitro Mammalian Cell Gene Mutation Tests Using the Thymidine Kinase Gene)

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian cell gene mutation tests using the thymidine kinase gene

Test material

Test material information

Constituent 1

Reference substance name:

p-vinylphenol

EC Number:

220-103-6

EC Name:

p-vinylphenol

Cas Number:

2628-17-3

Molecular formula:

C8H8O

IUPAC Name:

p-vinylphenol

Test material form:

solid: particulate/powder

Method

Species / strain

Species / strain / cell type:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Metabolic activation system:

Short-term treatment in the absence of metabolic activation (−S9 mix) Short-term treatment in the presence of metabolic activation (+S9 mix): 24-hour continuous treatment (−S9 mix): 1.32, 1.98, 2.96, 4.44, 6.67, 10.0 and 15.0 μg/mL

Test concentrations with justification for top dose:

In accordance with the specification of “Toxicity Study Guidelines”, the highest dose level was set at 1200 μg/mL (equivalent to 10 mM), and this was diluted using a common ratio of 2 to obtain a total of 9 concentrations (600, 300, 150, 75.0, 37.5, 18.8, 9.38 and 4.69 μg/mL).

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Remarks:

DMSO

Negative solvent / vehicle controls:

yes

True negative controls:

yes

Positive controls:

yes

Positive control substance:

cyclophosphamide

methylmethanesulfonate

Results and discussion

Test results

Key result

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

PHS has mutagenic potential in L5178Y TK+/-− -clone 3.7.2C cells under the conditions of this study.

Executive summary:

A dose range finding test and a gene mutation test were conducted for PHS using the mutations in the thymidine kinase gene loci in the cultured mouse lymphocytes (L5178Y TK+/− -clone 3.7.2C) cells with the short-term treatment and 24-hour continuous treatment.

Observation and measurement were performed after the treatment with the test article or the control articles for 3 hours for the short-term treatment and for 24 hours for the continuous treatment. Dimethyl sulfoxide (DMSO), the vehicle, was used as the negative control article and methyl methanesulfonate (MMS) and cyclophosphamide (CP) as the positive control articles for the treatment without and with metabolic activation, respectively.

Since cytotoxicity was occurred in the dose range finding test, the concentrations for the gene mutation test was selected to cover the cytotoxicity range from that producing cytotoxicity and including concentrations at which there is moderate and little or no cytotoxicity.

– Short-term treatment in the absence of metabolic activation (−S9 mix):

5.27, 7.90, 11.9, 17.8, 26.7, 40.0 and 60.0 μg/mL (common ratio: 1.5)

– Short-term treatment in the presence of metabolic activation (+S9 mix):

8.78, 13.2, 19.8, 29.6, 44.4, 66.7 and 100 μg/mL (common ratio: 1.5)

– 24-hour continuous treatment (−S9 mix):

1.32, 1.98, 2.96, 4.44, 6.67, 10.0 and 15.0 μg/mL (common ratio: 1.5)

In the judgment of the results, the indices calculated by addition of the Global Evaluation Factor (GEF: 126 × 10−6) to the total mutant frequency (T-MF) of the negative control group were used for evaluation according to recommendation of "OECD Guidelines for Testing of Chemicals 490".

In the gene mutation test, precipitation was not observed in any test article treatment group. Color of the culture medium did not change for any test article treatment group.

In the short-term treatment without metabolic activation, the T-MFs were 65.95, 132.75, 206.79, 314.11, 401.39, 800.00 and 871.09 × 10−6 at 5.27, 7.90, 11.9, 17.8, 26.7, 40.0 and 60.0 μg/mL, respectively, and the T-MFs at the dose level of 11.9 to 60.0 μg/mL were increased more than the indices calculated by addition of the GEF to the T-MF of the concurrent negative control group (73.63 × 10−6). However, the T-MFs at the dose levels of 40.0 and 60.0 μg/mL were excluded from the statistical analysis and the evaluation of the results, since the RTG was not higher than 10%. This treatment with the test article showed a significant dose-dependent

T-G327

9

T-MF increase (p < 0.05). According to the judging criteria, the result of the short-term treatment without metabolic activation was evaluated as positive.

In the short-term treatment with metabolic activation, the T-MFs were 88.95, 152.61, 205.27, 236.46, 302.97, 309.96, 413.79 × 10−6 at the dose levels of 8.78, 13.2, 19.8, 29.6, 44.4, 66.7 and 100 μg/mL, respectively, and the T-MFs at the dose levels of 19.8 to 100 μg/mL were increased more than the indices calculated by addition of the GEF to the T-MF of the concurrent negative control group (65.20 × 10−6). However, the T-MFs at the dose levels of 66.7 and 100 μg/mL were excluded from the statistical analysis and the evaluation of the results, since the RTG was not higher than 10%. This treatment with the test article also showed a significant dose-dependent T-MF increase (p < 0.05). According to the judging criteria, the result of the short-term treatment without metabolic activation was evaluated as positive.

In the continuous treatment, the T-MFs were 93.00, 62.97, 108.92, 98.93, 155.00, 246.84 and 288.02 × 10−6 at the dose levels of 1.32, 1.98, 2.96, 4.44, 6.67, 10.0 and 15.0 μg/mL, respectively, and the T-MFs at the dose levels of 10.0 and 15.0 μg/mL were increased more than the indices calculated by addition of the GEF to the T-MF of the concurrent negative control group (109.29 × 10−6). This treatment with the test article also caused a significant dose-dependent T-MF increase (p < 0.05). According to the judging criteria, the result of the continuous treatment without metabolic activation was evaluated as positive.

For the negative control group, the T-MF was within 50×10-6 to 170×10-6, the CE was within 0.65 to 1.20, and the TSG was between 8 to 32-fold in the short-term treatment and 32 to 180-fold in the continuous treatment. For the positive control group, the RTG was more than 10% and the S-MF increased 150×10-6 above the concurrent negative control group. For all the treatment groups, the number of evaluable dose levels was 4 or more. Therefore, it was judged that the study was conducted appropriately.

Based on the above results, it was concluded that PHS has mutagenic potential in L5178Y TK+/-− -clone 3.7.2C cells under the conditions of this study.