2-(methylamino)ethanol, compound with sulphur dioxide

Endpoint summary

Additional information

Genetic toxicity in vitro (weight of evidence)

A reliable Ames test with the source chemical 2 -(Methylamino)ethanol, performed according to protocols similar to OECD guideline 471 and using test substance concentrations up to 3333 µg/plate (Zeiger et al., 1987) revealed no mutagenic potential of the test substance both in the presence and the absence of a mammalian metabolic activation system. Salmonella typhimurium strains TA 98, TA 100, TA 1535 and TA 1537 were used as tester strains in a preincubation assay. The substance 2 -(Methylamino)ethanol did not induce mutation at the hprt locus of mouse lymphoma cells when tested up to highly toxic concentrations in 2 independent experiments in the presence and the absence of a rat liver metabolic activation system (Covance Laboratories Ltd, 2010; 8218080). Mutant frequencies in negative control cultures fell within normal ranges and clear increases in mutation were induced by the positive control chemicals (without and with S9 -mix). Therefore the study was accepted as valid. The source chemical 2 -(Methylamino)ethanol was also assessed for its potential to induce structural chromosomal aberrations (clastogenic activity) and/or changes in the number of chromosomes (aneugenic activity) in V79 cells both in the absence and in the presence of a metabolising system (BASF SE, 2008; 32M0540/074085). Following 4 -hour or 18 -hour exposure up to the highest recommended test substance concentration of 800 µg/mL (approximately 10 mM) with 18 -hour or 28 -hour sampling time, 2 -(Methylamino)ethanol did not cause any increase in the number of structural aberrant metaphases including and excluding gaps at both sampling times either with or without S9 -mix in 2 experiments performed independently of each other. The negative controls gave frequencies of aberrations within the range expected for the V79 cell line. Both of the positive control substances (without and with S9 -mix) led to the expected increase in the number of cells containing structural chromosomal aberrations, thus confirming sensitivity of the test system. Under the experimental conditions employed, the test substance had no chromosome-damaging (clastogenic) effect in vitro.

The source chemical Sodium sulfite was assayed for mutagenicity in the Ames test with the S. typhimurium strains TA 1535, TA 100, TA 1537 and TA 98 (BASF AG, 1989; 40MO639/884492)

. The bacterial strains were exposed to 20 - 5000 µg/plate in the standard and preincubation test, both with and without S9 –mix (BASF AG, 1989). The cytotoxicity was determined. No bacteriotoxic effects were observed. An increase in the number of his+ revertants was not observed, without or with S-9 mix. The source chemical Disodium disulfite was tested for mutagenicity in the Ames test with the S. typhimurium strains TA 1535, TA 100, TA 1537 and TA 98 (BASF AG, 1989; 40MO380/894265). The bacterial strains were exposed to 20 - 5000 µg/plate in the standard and preincubation test, both with and without S9-mix. The cytotoxicity was determined. No bacteriotoxic effects were observed. An increase in the number of his+ revertants was not observed both in the plate incorporation and in the preincubation test, without or with S9 -mix. According to the results of this study, the test substance was not mutagenic under the chosen experimental conditions.

The source chemical Disodium disulfite was assayed for the ability to induce mutation at the Hypoxanthine-guanine phosphoribosyl transferase (HPRT) locus (6-thioguanine [6TG] resistance) in mouse lymphoma cells (Covance Laboratories Ltd, 2010; 8230958). The study consisted of a cytotoxicity range-finder experiment followed by three independent experiments, each conducted in the absence and/or presence of a mammalian metabolic activation system (S9 -mix). The test substance was formulated in purified water. A 3 -hour treatment incubation period was used for all experiments. In the cytotoxicity range-finder experiment, concentrations were tested in the absence and presence of S9 mix, ranging from 59.44 to 1902 µg/mL (equivalent to 10 mM at the highest concentration tested). The highest concentration analysed gave 37 % and 50 % relative survival (RS) in the absence and presence of S9 mix, respectively. In Experiment I, concentrations ranging from 200 to 1902 µg/mL were tested in the absence and presence of S9 mix. Seven days after treatment, the highest concentration analysed in the absence and presence of S9 mix gave 43 % and 65 % RS, respectively. In Experiment II, concentrations ranging from 100 to 1902 µg/mL were tested in the absence and presence of S9 mix. Seven days after treatment, the highest concentration analysed in the absence and presence of S9 mix gave 30 % and 75 % RS. In Experiment III, concentrations ranging from 200 to 1902 µg/mL were tested in the presence of S9 mix. Seven days after treatment, the highest concentration analysed gave 43 % RS. Vehicle and positive control treatments were included in each mutation experiment. In Experiment I in the presence of S9 mix, statistically significant increases in mutant frequency were observed at the highest 2 concentrations (1600 and 1902 µg/mL). However, there was no significant linear trend. These data did not fulfil all the criteria for a positive result and were therefore considered equivocal. In Experiment I in the absence of S9 mix and Experiment II in the absence and presence of S9 mix no significant increases in mutant frequency were observed following treatment with the test substance at any concentration and there were no significant linear trends, indicating a negative result. In order to confirm this negative result a confirmatory experiment in the presence of S9 mix was performed. In Experiment III, no statistically significant increases in mutant frequency were observed following treatment with the test substance at any concentration tested and there were no significant linear trends, indicating a negative result.

Genetic toxicity in vivo (weight of evidence)

The source chemical Sodium sulfite was tested for chromosomal damage induction (clastogenicity) and for its ability to induce spindle poison effects (aneugenic activity) in NMRI mice using the micronucleus test method (BASF SE, 2008; 26MO250/084046). For this purpose, the test substance, dissolved in purified water, was administered once subcutaneously to groups of male animals at dose levels of 250, 500 or 1000 mg/kg bw in a volume of 10 mL/kg bw in each case. Purified water was used as the vehicle control, administered by the same route. Cyclophosphamide and Vincristine sulfate were used as positive control substances. The animals were sacrificed and the bone marrow of the 2 femora was prepared 24 and 48 hours after administration in the highest dose group of 1000 mg/kg bw and in the vehicle controls. In the test groups at 500 and 250 mg/kg bw and in the positive control groups, the 24 -hour sacrifice interval was investigated only. After staining of the preparations, 2000 polychromatic erythrocytes (PCEs) were evaluated per animal and investigated for micronuclei. The normocytes (NCEs) with and without micronuclei occurring per 2000 PCEs were also recorded. According to the results of this study, the single subcutaneous administration of the test substance did not lead to any relevant increase in the number of PCEs containing either small or large micronuclei. The rate of micronuclei was always close to the range as that of the concurrent vehicle control in all dose groups and at all sacrifice intervals and within the range of the historical vehicle control data. Under the experimental conditions, the test substance had no chromosome damaging (clastogenic) effect, and there were no indications of any impairment of chromosome distribution in the course of mitosis (aneugenic activity) in bone marrow cells in vivo.

Justification for selection of genetic toxicity endpoint
No endpoint selection was conducted, since several reliable studies with the relevant source chemicals were identified to assess the genetic toxicity hazard displayed by the target chemical 2-(Methylamino)ethanol, compound with Sulfur dioxide, (weight-of-evidence).

Short description of key information:
The in vitro and in vivo studies on genetic toxicity conducted with the source chemicals 2-(Methylamino)ethanol or Sodium sulfite/Disodium disulfite demonstrated that none of the source chemicals displayed a genotoxic hazard in aqueous formulations. On the basis of the weight-of-evidence, the target chemical 2-(Methylamino)ethanol, compound with Sulfur dioxide, which is the salt of the source chemicals, is identified as a substance without genotoxic activity.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the results of reliable studies obtained in vitro and in vivo for the source chemicals 2 -(Methylamino)ethanol and Sodium sulfite/Disodium disulfite (weight-of-evidence), the target chemical 2 -(Methylamino)ethanol, compound with Sulfur dioxide, is not considered to be subject to classification for genetic toxicity according to Directive 67/548/EEC (DSD) and Regulation (EC) No 1272/2008 (GHS/CLP).