2-Propenoic acid, 2-methyl-, C11-14-isoalkyl esters, C13-rich

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

consistenty negative in a bacteria reverse mutation assay (OECD TG 471; RL1, GLP), mammalian cell gene mutation assay (OECD TG 476, RL1, GLP) and chromosome aberration assay (OECD TG 473, RL1, GLP); read-across from Isodecyl methacrylate

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

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

Adequacy of study:

weight of evidence

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 physicochemical, ecotoxicological and toxicological properties because
• they are manufactured from similar or identical precursors under similar conditions
• they share structural similarities with common functional groups: methacrylate esters
• the metabolism pathway leads to comparable products (methacrylic acid and medium chain alcohol).

Therefore, read-across from the existing physicochemical, ecotoxicity and toxicity 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

Reason / purpose for cross-reference:

read-across: supporting information

Type of assay:

bacterial reverse mutation assay

Positive controls:

yes

Remarks:

for TA 1535, TA 1537, TA 98, TA 100, TA 102

Positive control substance:

other: 2-aminoanthracene, with metabolic activation

Remarks:

2-aminoanthracene (purity: > 99%, supplier: MERCK, D-64293 Darmstadt, Germany) dissolved in DMSO; concentration: 2.5 µg/plate (10 µg/plate in TA 102)

Species / strain:

other: Salmonella typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

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

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results: negative

Reference 2

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

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

Adequacy of study:

weight of evidence

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 physicochemical, ecotoxicological and toxicological properties because
• they are manufactured from similar or identical precursors under similar conditions
• they share structural similarities with common functional groups: methacrylate esters
• the metabolism pathway leads to comparable products (methacrylic acid and medium chain alcohol).

Therefore, read-across from the existing physicochemical, ecotoxicity and toxicity 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

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain:

lymphocytes: human, short-term culture

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: strain/cell type: Human Lymphocytes

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results: negative

Reference 3

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:

weight of evidence

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 physicochemical, ecotoxicological and toxicological properties because
• they are manufactured from similar or identical precursors under similar conditions
• they share structural similarities with common functional groups: methacrylate esters
• the metabolism pathway leads to comparable products (methacrylic acid and medium chain alcohol).

Therefore, read-across from the existing physicochemical, ecotoxicity and toxicity 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

Reason / purpose for cross-reference:

read-across: supporting information

Type of assay:

mammalian cell gene mutation assay

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

in forward gene mutations in mammalian cells

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 1200 µg/mL with S9 mix; at 1.0 µg/mL and above in Experiment I and 37.5 µg/mL in Experiment II without S9 mix

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: strain/cell type: V79

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results: negative

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

No experimental data on Isotridecyl methacrylate are available for the assessment of genetic toxicity. However, studies are available for the source substance Isodecyl methacrylate. A detailed justification for read-across is attached to IUCLID section 13.

 

The absence of a mutagenic potential was demonstrated for gene mutations as well as chromosome aberrations for Isodecyl methacrylate. These results are representative for the target substance, as Isodecyl methacrylate represents a worst-case in terms of bioavailability due to its molecular size, lipophilicity and water solubility.

 

Hypothesis for the analogue approach

The read-across hypothesis relies on the close structural similarity between the source substance Isodecyl methacrylate and the target substance Isotridecyl methacrylate. his read-across hypothesis corresponds to scenario 2 - different compounds have qualitatively similar properties - of the read-across assessment framework i.e. properties of the target substance are predicted to be quantitatively equal to those of the source substance. Namely, the structurally similar source substance Isodecyl methacrylate predicts the toxicological properties of the target substance Isotridecyl methacrylate.

 

Toxicological data are summarised in the data matrix; robust study summaries are included in the Technical Dossier in the respective sections.

 

Therefore, read-across from the existing toxicity studies conducted with the source substance is considered as an appropriate adaptation to the standard information requirements of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of the REACH Regulation.

A detailed justification for the proposed read-across approach is attached to Iuclid section 13.

 

1. Identity and characterisation of the source substance

 

There is close structural similarity between the source and the target substances and the identity and characterisation of these substances is unambiguous thereby giving a high level of confidence in the validity of the read across.

The target and source substances are manufactured from similar compounds by esterification of methacrylic acid with the corresponding fatty alcohol. Typical trace impurities are water and the corresponding alcohols as well as < 1 % methacrylic acid, which are not of toxicological concern.

The carbon chain length distribution of the resulting mix of long-chain aliphatic methacrylate esters mirrors the chain length distribution of the alcohol(s) used.

 

2. Link of structural similarities and differences with the proposed prediction

Structural similarities:

The target substance Isotridecyl methacrylate is an ester of Methacrylic acid and branched C12-C18 alcohols. The source substance Isodecyl methacrylate contains branched alkyl chains as well, though it has shorter C-chains (C10).

 

Structural differences:

There are differences in alkyl chain length between the target and the source substances.

The source substance Isodecyl methacrylate can be expected to have a slightly higher bioavailability due to lower molecular weight compared to the target substance.

The physicochemical properties (low water solubility and high log Kow) are, however, quite similar. Thus, no large differences in bioavailability are expected.

 

Reliability and adequacy of the source data

All available studies have been conducted according to OECD guidelines and have been assigned a reliability of 1 or 2 as documented in the data matrix (see detailed justification for read-across attached to Iuclid section 13).

 

Overall, the study design of the respective source studies is adequate and reliable for the purpose of this read-across. The results of the selected key studies are adequate for classification and labelling and for risk assessment purposes.

 

 

Data availability

Reverse gene mutation assay in bacteria

In a reverse gene mutation assay in bacteria (Ames test), strains TA1535, TA1537, TA98, TA100, and TA102 of Salmonella typhimurium were exposed to Isodecyl methacrylate at concentrations of up to 5000 µg/plate in the presence and absence of mammalian metabolic activation S9 -mix. 

No toxic effects occurred in the test groups with and without metabolic activation.The plates incubated with the test article showed normal background growth up to ug/plate with and without S9-mix in all strains used. No substantial increases in revertant colony numbers of any of the five tester strains were observed following treatment with at any concentration level, either in the presence or absence of metabolic activation (S9 -mix). There was also no tendency to higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance.

Appropriate reference mutagens were used as positive controls.

The positive controls induced the appropriate responses in the corresponding strains.

There was no evidence of induced mutant colonies over background.

Therefore, Isodecyl methacrylate is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.

 

Chromosome aberration test

The test item Isodecyl methacrylate, dissolved in THF, was assessed for its potential to induce structural chromosomal aberrations in human lymphocytes in vitro in two independant experiments.

The study design was performed as follows:

Experiment I: 22 hrs preparation interval, 4 hrs exposure period without and with S9 mix

Experiment II: 22 hrs prep. interval, 22 hrs exposure period without S9 mix and 22 hrs prep. interval, 4 hrs exposure period with S9 mix.

In each experimental group, two parallel cultures were analysed. Per culture 100 metaphase plates were scored for structural chromosomal aberrations, except for the positive controls in Experiment I, in the presence of S9 mix and Experiment II, in the absence of S9 mix, where 50 metaphase plates were scored due to strong clastogenic effects.

The highest applied concentration in Experiment I (2333.0 µg/ml of the test item, approx. 9.9 mM) was chosen with regard to the solubility of the test item in an appropriate solvent (THF) and with respect to the current OECD Guideline 473.

Dose selection of the cytogenetic experiment was performed considering the toxicity data and the occurrence of test item precipitation in accordance with OECD Guideline 473.

In Experiment I, visible precipitation of the test item in the culture medium was observed at 136.0 µg/ml and above in the absence and presence of S9 mix. In addition, precipitation occurred in Experiment II, in the absence of S9 mix, at 136.0 µg/ml and above and in the presence of S9 mix at 416.7 µg/ml and above. No relevant increase in the osmolarity or pH value was observed. In Experiment I, in the absence and presence of S9 mix, and in Experiment II, in the presence of S9 mix, no cytotoxicity was observed up to the highest applied concentration. In Experiment II, in the absence of S9 mix, a single clearly reduced mitotic index was observed at the highest dose evaluated for cytogenetic damage.

In both independent experiments, neither a statistically significant nor a biologically relevant increase in the number of cells carrying structural chromosomal aberrations was observed after treatment with the test item.

No relevant increase in the frequencies of polyploid metaphases was found after treatment with the test item as compared to the frequencies of the controls.

Appropriate mutagens were used as positive controls. They induced statistically significant increases (p < 0.05) in cells with structural chromosome aberrations.

In conclusion, it can be stated that under the experimental conditions reported, the test item did not induce structural chromosomal aberrations as determined by the chromosome aberration test in human lymphocytes in vitro.

Therefore, the test substance is considered to be non-clastogenic under the experimental conditions reported.

 

in vitro gene mutation study in mammalian cells

Isodecyl methacrylate was assessed for its potential to induce gene mutations at the HPRT locus using V79 cells of the Chinese hamster.

The assay was performed in two independent experiments with identical experimental procedures, using two parallel cultures each. The first main experiment was performed with and without liver microsomal activation and a treatment period of 4 h. The second experiment was performed with a treatment period of 24 hours in the absence of metabolic activation and 4 hours in the presence of metabolic activation.

The cell cultures were evaluated at the following concentrations:

Experiment I:

without S9 mix:  0.1; 0.3; 0.5; 1.0; and 2.0 µg/ml

with S9 mix: 37.5; 75; 150; 300; and 1200 µg/ml

 

Experiment II:

without S9 mix: 18.8 ;37.5; 75.0; 150; and 600 µg/ml

with S9 mix: 37.5; 75.0; 150; 300; and 600 µg/ml

 

Phase separation of the test item was observed at 300 µg/mL and above in the first experiment with metabolic activation and at 150 µg/mL and above in the second experiment without metabolic activation. In the second experiment with metabolic activation phase separation was noted at 300 µg/mL and above.

Relevant toxic effects indicated by a relative cloning efficiency 1 below 50 % occurred at 1.0 µg/mL and above in the first experiment without metabolic activation and at 1200.0 µg/mL and above with metabolic activation. In the second experiment toxic effects as described above occurred at 37.5 µg/mL without metabolic activation and at 1200 µg/mL with metabolic activation. The striking difference of toxic concentrations with and without metabolic activation is probably based on protein or lipid binding effects. In the presence of metabolic activation the protein and lipid concentration is higher due to the S9-mix added.This fact is furthermore supported by the considerably less severe cytotoxicity following 24 h treatment without metabolic activation. During long term exposure 10 % FCS have to be added increasing the protein and lipid concentration of the medium.

No relevant and reproducible increase in mutant colony numbers/106cells was observed in the main experiments up to the maximum concentration.

The induction factor reached or exceeded the threshold of three times the corresponding solvent control in experiment I at 37.5 µg/mL in the first culture with metabolic activation and at the same concentration in the first culture in experiment II without metabolic activation. However, both effects were judged as biologically irrelevant fluctuations since no increase was observed at higher concentrations or in the parallel cultures under identical conditions. Furthermore, the effects were not dose-dependent as indicated by the lacking statistical significance.

In both experiments of this study (with and without S9 mix) the range of the solvent controls was from 5.7 up to 24.0 mutants per 106cells; the range of the groups treated with the test item was from 3.3 up to 34.1 mutants per 106cells.

EMS(150 µg/mL in experiment I and 75 µg/mL in experiment II) and DMBA (2.0 µg/mL) were used as positive controls and showed a distinct increase in induced mutant colonies. This showed the sensitivity of the test system and the activity of the S9 mix.

In conclusion it can be stated that under the experimental conditions reported the test item did not induce gene mutations at the HPRT locus in V79 cells.

Therefore, Isodecyl methacrylate is considered to be non-mutagenic in this HPRT assay.

 

 

There are no data gaps for the endpoint genetic toxicity. There is no reason to believe that the results would not be relevant to humans.  

Justification for classification or non-classification

Based on the available data, Isotridecyl methacrylate does not need to be classified for genetic toxicity according to the criteria given in regulation (EC) 1272/2008. Thus, no labelling is required.