2,5,8,11-tetramethyldodec-6-yne-5,8-diol

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

According to the UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Part 3 Chapter 3.5 this substance is not causing concern to be mutgenetic/genetic toxic.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2010

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source and target substances have similar toxicological properties because
- they are manufactured from similar precursors under similar conditions
- they share structural similarities with common functional groups: the substances start with an acetylene group as core structure; geminal hydroxyl groups on the alpha carbon atoms; distal to the geminal hydroxyl groups is an isobutyl group (methyl isopropyl); the target substance 2,4,7,9-Tetramethyl-5-decyne-4,7-diol, ethoxylated (1.3) is further functionalised with ethylene oxide and has an ethoxylation degree of 1.3; the source substance 2,4,7,9-Tetramethyl-5-decyne-4,7-diol, ethoxylated (3.8) has an ethoxylation degree of 3.8
- they have similar physicochemical properties and thus, show a similar toxicokinetic behaviour
- they are expected to undergo similar metabolism: oxidation of the terminal methyl groups to result in alcohol, aldehyde and finally the corresponding acid

Therefore, read-across from the existing toxicity, ecotoxicity, environmental fate and physicochemical studies on the source substances is considered as an appropriate adaptation to the standard information requirements of REACH regulation.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
see “Justification for read-across” attached to IUCLID section 13

3. ANALOGUE APPROACH JUSTIFICATION
see “Justification for read-across” attached to IUCLID section 13

4. DATA MATRIX
see “Justification for read-across” attached to IUCLID section 13

Reason / purpose for cross-reference:

read-across source

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Two independent experiments wre performed. In Experiment 1, L5178Y TK +/- 3.7.2c mouse lymphoma cells (heterozyous at the thymidine kinase locus) were treated with the test material at up to eight dose levels, in duplicate, together with vehicle (solvent) and positive controls using 4 -hour exposure groups both in the asence and presence of metabolic activation (2% S9). In experiment 2, the cells were treated with the test material at up to eight dose levels using a 4 -hour exposure group in the absence of metabolic activation.
The dose range of test material was selected following the results of a preliminary toxicity test and for the first experiment was 4.38 to 140 µg/ml in the absence of metabolic activation, and 17.5 to 280 µg/ml in the presence of metabolic activation. For the second experiment the dose range was 4.38 to 140 µg/ml in the absence of metabolic activation, and 17.5 to 210 µg/ml in the presence of metabolic activation.

Conclusions:

The test material was considered to be non-mutagenic to L5178Y cells under the conditions of the test.

Executive summary:

Introduction:

The study was conducted according to a method that was designed to assess the potential mutagenicity of the test material on the thymidine kinase, TK +/-, locus of the L5178Y mouse lymphoma cell line, >>The method used meets the requirements of the OECD (476) and the Method B17 of Commission Regulation (EC) No. 440/2008 of 30 May 2008.

Methods:

Two independent experiments wre performed. In Experiment 1, L5178Y TK +/- 3.7.2c mouse lymphoma cells (heterozyous at the thymidine kinase locus) were treated with the test material at up to eight dose levels, in duplicate, together with vehicle (solvent) and positive controls using 4 -hour exposure groups both in the asence and presence of metabolic activation (2% S9). In experiment 2, the cells were treated with the test material at up to eight dose levels using a 4 -hour exposure group in the absence of metabolic activation.

The dose range of test material was selected following the results of a preliminary toxicity test and for the first experiment was 4.38 to 140 µg/ml in the absence of metabolic activation, and 17.5 to 280 µg/ml in the presence of metabolic activation. For the second experiment the dose range was 4.38 to 140 µg/ml in the absence of metabolic activation, and 17.5 to 210 µg/ml in the presence of metabolic activation.

Results:

THe maximum dose level used in the mutagenicity test was limited by test material-induced toxicity. Precipitate of the test material was not observed at any of the dose levels in the mutagenicity test. The vehicle (solvent) controls had acceptable mutant frequency values that were within the normal range for the L5178Y cel line at the TK +/- locus. The positive control materials induced marked increases in the mutant frequency indicating the satisfactory perfomance of the test and of the activity of the metabolising system.

The test material did not induce any toxicologically significant dose-related increases in the mutant frequency at any dose level, either with or without metabolic activation, in either the first or the second experiment.

Conclusion:

The test material was considered to be non-mutagenic to L5178Y cells under the conditions of the test.

Reference 2

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:

2010

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)

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

lymphocytes: human

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 Mix

Test concentrations with justification for top dose:

19.2 (µg/ml)
33.5 (µg/ml)
58.7 (µg/ml)
102.7 (µg/ml)
179.7 (µg/ml)
314.5 (µg/ml)
550.4 (µg/ml)
963.3 (µg/ml)
1685.7 (µg/ml)
2950.0 (µg/ml)

Vehicle / solvent:

acetone

Negative solvent / vehicle controls:

yes

Remarks:

acetone

Positive controls:

yes

Positive control substance:

cyclophosphamide

ethylmethanesulphonate

Key result

Species / strain:

lymphocytes: human

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

The test item, dissolved in acetone, was assessed for its potential to induce chromosomal aberrations in human lymphocytes in vitro in the absence and presence of metabolic activation by S9 mix. Two independent experiments were performed. In Experiment I, the exposure period was 4 hours with and without S9 mix. In Experiment II, the exposure period was 4 hours with S9 mix and 22 hours without S9 mix. The chromosomes were prepared 22 hours (Exp. I & II) after start of treatment with the test item. In each experimental group two parallel cultures were analysed. 100 metaphases per culture were scored for structural chromosomal aberrations. 1000 cells were counted per culture for determination of the mitotic index. The highest treatment concentration in this study, 2950.0 Ng/mL (approx. 11.4 mM) was chosen with respect to the OECD Guideline for in vitro mammalian cytogenetic tests. Visible precipitation of the test item in the culture medium was observed at 179.7 Ng/mL and above in Experiment I and II in the presence of S9 mix. No relevant increase in the osmolarity or pH value was observed (Exp. I: solvent control: 376 mOsm, pH 7.3 versus 343 mOsm and pH 7.4 at 2950.0 Ng/mL; Exp. II: solvent control: 371 mOsm, pH 7.3 versus 384 mOsm and pH 7.3 at 102.7 Ng/mL). Phase separation was observed in Experiment I in the absence of S9 mix at 179.9 NL/mL and above at the end of treatment. In Experiment I in the absence and presence of S9 mix and in Experiment II in the presence of S9 mix, cytotoxicity was observed at the highest evaluated concentrations (24.3, 51.7 and 27.0 % of control). In Experiment II in the absence of S9 mix concentrations showing clear cytotoxicity were not scorable for cytogenetic damage (Table 3 and 4, pages 22 and 23). In both experiments, in the absence and presence of S9 mix, no biologically relevant increase in the number of cells carrying structural chromosome aberrations was observed (see Table 6, 7, 9 and 10, pages 25, 26, 28 and 29). The aberration rates of the cells after treatment with the test item (0.0 – 2.5 % aberrant cells, excluding gaps) were close to the range of the solvent control values (0.0 - 1.5 % aberrant cells, excluding gaps) and within the range of the laboratory´s historical solvent control data (see ANNEX III). Two statistically significant increases were observed in Experiment II in the absence of S9 mix after treatment with 6.3 and 11.0 Ng/mL (2 % aberrant cells, excluding gaps). These values are within the laboratory´s historical solvent control data range (0.0 – 2.5 % aberrant cells, excluding gaps) and therefore the statistical significance has to be regarded as being biologically irrelevant. Table 5 and 8, pages 24 and 27, show the occurrence of polyploid metaphases. The rates of polyploid metaphases after treatment with the test item (0.0 – 0.6 %) were close to the rates of the solvent controls (0.0 – 0.4 %) and within the range of the laboratory’s historical control data (see ANNEX III). In both experiments, either EMS (660.0 or 825.0 Ng/mL) or CPA (7.5 or 15.0 Ng/mL) were used as positive controls and showed distinct increases in cells with structural chromosome aberrations. In conclusion, it can be stated that under the experimental conditions reported, the test item Surfynol® 124 Surfactant did not induce structural chromosomal aberrations in human lymphocytes in vitro, when tested up to cytotoxic, precipitating or the highest evaluable concentrations.

Conclusions:

negative

It can be stated that under the experimental conditions reported, the test item did not induce structural chromosomal aberrations in human lymphocytes in vitro, when tested up to cytotoxic, precipitating or the highest evaluable concentrations.

Reference 3

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

0 (µg/plate)
1.5 (µg/plate)
5 (µg/plate)
15 (µg/plate)
50 (µg/plate)
150 (µg/plate)
500 (µg/plate)
1500 (µg/plate)

Vehicle / solvent:

DMSO

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

The vehicle (dimethyl sulphoxide) control plates gave counts of revertant colonies within the normal range. All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with or without metabolic activation. Thus, the sensitivity of the assay and the efficacy of the S9-mix were validated. In the first experiment (plate incorporation method) the test material caused a visible reduction in the growth of the bacterial background lawns of all of the bacterial strains at and above 1500 ug /plate in both the presence and absence of S9-mix. In the second experiment (pre-incubation method) the test material induced toxicity to the bacterial background lawns of all of the tester strains, initially from 150 and 500 ug /plate, in the absence and presence of S9-mix, respectively. The test material was tested up to the maximum recommended dose level of 5000 ug /plate in the range-finding test and the toxic limit in the main test. A clear, particulate precipitate (crystalline in appearance under an inverted microscope) was observed at 5000 ug /plate, this observation did not prevent the scoring of revertant colonies. No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, with any dose of the test material, either with or without metabolic activation or exposure method.

Conclusions:

The test material was considered to be non-mutagenic under the conditions of this test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Mode of Action Analysis / Human Relevance Framework

There is no evidence for species specific effects of the substance. Therefore, the results of the in vitro data are regarded as relevant for humans. 

Justification for classification or non-classification

According to the UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Part 3 Chapter 3.5 this substance is not causing concern to be mutgenetic/genetic toxic.