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Administrative data

Key value for chemical safety assessment

Additional information

For genetic toxicity, there was no study with registered substance, but read across data were available from source substances Butanedioic acid, sulfo-, 1,4-bis(1,3-dimethylbutyl) ester, sodium salt (CAS No. 2373 -38 -8) and Docusate sodium (CAS No. 577 -11 -7).

Bacterial mutagenicity

- In a key Ames test (Flügge, 2013) Butanedioic acid, sulfo-, 1,4-bis(1,3-dimethylbutyl) ester, sodium salt (CAS No. 2373 -38 -8) was examined in the 5 Salmonella typhimurium strains TA98, TA100, TA102, TA1535 and TA1537 in two independent experiments, each carried out without and with metabolic activation up to concentration of 5000 µg/plate. The first experiment was carried out as a plate incorporation test and the second as a preincubation test. No signs of cytotoxicity were noted in the plate incorporation test and in the preincubation test. No increase in revertant colony numbers as compared with control counts was observed for the test item up to 5000 µg/plate, in any of the 5 test strains in two independent experiments without and with metabolic activation, respectively.

- In a supporting study, Docusate sodium (CAS No. 577 -11 -7) was tested in 5 Salmonella typhimurium strains TA98, TA100, TA102, TA1535 and TA1537 (Clare 1993). After a range-finder experiment showing cytotoxicity at the highest concentration of 5000 µg/plate, maximum test concentrations of 1000 and 2500 µg/plate were chosen for the main experiment 1. In experiment 1, concentrations were close to the limit of toxicity, therefore for experiment 2, concentrations for all strains were maximally 2000 µg/plate without S9 and 2500 µg/plate with S9. In both experiments, Docusate sodium did not result in statistically significant increases in revertant number of colonies, both with and without S9.

Mammalian gene mutation

- In a key Mouse Lymphoma assay in the cell line L5178Y (Wollny, 2006), Butanedioic acid, sulfo-, 1,4-bis(1,3-dimethylbutyl) ester, sodium salt (CAS No. 2373 -38 -8) containing 80% active ingredient was assessed for its potential to induce mutations in the mouse lymphoma thymidine kinase locus using the cell line L5178Y with and without liver microsomal activation and a treatment period of 4h. After a dose range finding study, two independent experiments with in duplo cell cultures were tested up to highly toxic concentrations leading to 10 -20% viability. No substantial and reproducible dose dependent increase in mutant colony numbers was observed in both main experiments. No relevant shift of the ratio of small versus large colonies was limited by toxicity of the test item. Under the experimental conditions reported, the test substance did not induce mutations in the mouse lymphoma thymidine kinase locus assay using the cell line L5178Y in the absence and presence of metabolic activation.

Chromosome aberration

- Butanedioic acid, sulfo-, 1,4-bis(1,3-dimethylbutyl) ester, sodium salt (CAS No. 2373 -38 -8) containing 80% active ingredient was tested in a key Chromosome aberration toxicity study according to OECD 473 in V79 cell of the Chinese hamster in vitro (Schulz, 2003), in two independent experiments up to 5000 µg act.ingr./mL (approx. 10 mM of the active ingredient). In each experimental group two parallel cultures were set up. Per culture 100 metaphase plates were scored for structural chromosome aberrations. Toxic effects indicated by reduced cell numbers and/or mitotic indices of about and below 50% of control were observed in all experimental parts. However, in experiment I in the absence and the presence of S9 mix concentrations showing clear cytotoxicity were not evaluable for cytogenetic damage. In both independent experiments, no biologically relevant increase in the number of cells carrying structural and numerical chromosomal aberrations was observed after treatment with the test item. Appropriate mutagens were used as positive controls.

- Docusate sodium was tested in a supporting Chromosome aberration toxicity study according to OECD 473 in V79 CHO cells (Marshall 1994). The highest dose level used, 470 µg/mL was close to the solubility limit in culture medium. In the absence of S9, frequencies of cells with aberration were similar to and not significantly different from negative controls. Numbers of aberrant cells in all treated cultures fell within (or very close to) the historical negative control range. In the presence of S9 (Experiment 1) significantly increased frequencies of cells with aberrations were seen at the highest dose level for analysis (120µg/mL) which fell outside the historical negative control range. In contrast, cultures treated and sampled under these conditions in Experiment 2 had normal frequencies of aberrant cells at all dose levels analysed, however the highest concentration failed to induce 50% mitotic inhibition. This part of the assay was therefore repeated on 2 further occasions using a smaller interval, however, it was not possible to achieve 50-75% mitotic inhibition. The highest scorable dose in the second trial was 130 µg/ml and slides from these cultures were analyzed. Due to applicant and author, small but statistically significant increases in cells with aberrations were seen at both 125 and 130 µg/ml, however the effect was considered to be of marginal biological significance because numbers of aberrant cells fell outside the normal range in only a single replicate at the highest dose. Author further mentioned that most likely aberration induction involved an indirect mechanism. Therefore induction of chromosome aberration is not concluded based on the opinion of the applicant.

Conclusion

- Standard information requirements according to REACH Guidance Part 3 R7a were fulfilled for genotoxicity testing, including bacterial and mammalian mutagenicity and chromosomal aberration. Based on the available results, there were no indications of mutagenicity or genotoxicity, and no further testing is needed. The substance can be considered to have no mutagenic or genotoxic potential.

- Further information supporting the safety of the test substance is provided in the read across justification for the Di-ester category, showing that all substances were negative for the various genotoxicity endpoints (justification with data matrix separately attached in Section 13).

 


Justification for selection of genetic toxicity endpoint
Although the Ames test was selected as key study, the other genotoxicity enpoints were considered equally important.

Short description of key information:
Key and supporting studies were available for the various in vitro genotoxicity endpoints, including bacterial reverse muation in the Ames test in Salmonella typhimurium strains TA98, TA100, TA102, TA1535 and TA1537, mammalian gene mutation in the Mouse Lymphoma assay in the cell line L5178Y, and chromosome aberration in the Chromosome aberration assay in V79 Chinese hamster cells. In all systems, results were negative either without and with metabolic activation. The results were based on read across substances wihtin the category of Diesters, and were confirmed by other negative studies in the same category.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the negative findings with read across data, the test item does not need to be classified and has no obligatory labelling requirement for genotoxicity according to the EC Directive (No.93/21/EEC) and CLP (No. 1272/2008 of 16 December 2008).