2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-1,3-propanediol hydrochloride

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In a study according to OECD TG 471 under GLP conditions, the read-across substance was not mutagenic in five strains (TA98, TA100, TA1535, TA1537 and WP2 uvrA) with and without metabolic activation (reference 7.6.1 -1).

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Please refer to section 13 for the read-across justification.

Reason / purpose for cross-reference:

read-across source

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

True negative controls validity:

not applicable

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

True negative controls validity:

not applicable

Positive controls validity:

valid

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

True negative controls validity:

not applicable

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

True negative controls validity:

not applicable

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

True negative controls validity:

not applicable

Positive controls validity:

valid

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Genetic toxicity in vitro

No study data with the test item is available for genetic toxicity. Therefore, a read-across to the read-across substance with a very similar chemical structure and comparable physico-chemical parameters is used to evaluate the potential of the test item to cause genetic toxicity.

Ames

The read-across substance was tested with regard to a potential mutagenic activity using the Bacterial Reverse Mutation Assay according to OECD 471.

The experiments were carried out using histidine-requiring auxotroph strains of Salmonella typhimurium (Salmonella typhimurium TA98, TA100, TA1535 and TA1537), and the tryptophan-requiring auxotroph strain of Escherichia coli (Escherichia coli WP2 uvrA) in the presence and absence of a post mitochondrial supernatant (S9) prepared from livers of Phenobarbital/β-naphthoflavone-induced rats.

The study included a Preliminary Solubility Test, a Preliminary Range Finding Test (Informatory Toxicity Test), an Initial Mutation Test (Plate Incorporation Test), and a Confirmatory Mutation Test (Pre-Incubation Test).

Based on the results of the Solubility and the Range Finding Tests the read-across substance was dissolved in ultrapure water (ASTM Type 1). This vehicle was compatible with the survival of the bacteria and the S9 activity.

Based on the results of the preliminary Range Finding Test the following concentrations of the read-across substance were prepared and investigated in the Initial and Confirmatory Mutation Tests:

5000; 1600; 500; 160; 50 and 16 μg/plate.

In the preliminary experiments the pH of the aqueous read-across substance solution (50 mg/mL) was found as 9.24. Extremes of pH could have influencing effect on the mutagenicity results, therefore in the Initial and Confirmatory Mutation Tests the pH of the read-acoss substance stock solution (prepared for the highest concentration of 50 mg/mL) and additionally the pH of the overlay (top agar-phosphate buffer-test item system (at 50 mg/mL)) was checked and recorded. The pH values of the read-across substance stock solution (50 mg/mL) were 9.39 and 9.18. The pH of the substance containing overlays was in the range of 7.44 - 7.50 in both experiments. In this study the alkaline read-across substance solutions had only slight effect on the buffered overlay system. Unequivocal negative results were obtained and the additional information about the pH conditions was not involved into the mutagenicity result interpretation.

No precipitation of the read-across substance was observed on the plates in the examined bacterial strains at any examined concentration level (±S9 Mix) throughout the study.

The read-across substance did not show inhibitory, cytotoxic effects in the performed experiments. The colony and background lawn development was not affected in any case; the obtained revertant colony number decreases (compared to the revertant colony numbers of the vehicle control) remained within the biological variability range of the applied test system.

The revertant colony numbers of vehicle control (ultrapure water) plates with and without S9 Mix demonstrated the characteristic mean number of spontaneous revertants that was in line with the corresponding historical control data ranges.

The reference mutagen treatments (positive controls) showed the expected, biological relevant increases in induced revertant colonies in all experimental phases, in all tester strains, thus, showing the expected reversion properties of all strains and good metabolic activity of the S9 mix used.

No biologically relevant increases were observed in revertant colony numbers of any of the five test strains following treatment with the read-across substance at any concentration level, either in the presence or absence of metabolic activation (S9 Mix) in the performed experiments.

The reported data of this mutagenicity assay show that under the experimental conditions applied, the read-across substance did not induce gene mutations by base pair changes or frameshifts in the genome of the bacterium tester strains used.

In conclusion, the read-across substance has no mutagenic activity on the applied bacterium tester strains under the test conditions used in this study.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. As a result the substance is not considered to be classified for genotoxicity under Regulation (EC) No 1272/2008, as amended for the fifteenth time in Regulation (EU) No 2020/1182.