Sodium N-methyltaurinate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The publication by Zeiger et al. reports that the read-across substance N-methyltaurine does not exhibit genetic toxicity in a bacterial reverse mutation assay (Ames test) using various Salmonella typhimurium strains in the presence or absence of metabolic activation with liver S-9 mixes. Concentrations of up to 10 mg of N-methyltaurine per plate were tested. N-methyltaurinate is the deprotonated form of N-methyltaurine. Both sodium N-methyltaurinate and N-methyltaurine are highly soluble in water. Therefore, it is expected that both substances behave similarly in aqueous solution. Hence, the experimental data on N-methyltaurine provide a reasonable measure for the genetic toxicity of sodium N-methyltaurinate.

This result is supported by the OECD 471 guideline study on sodium N-methyltaurinate, where no genetic toxicity has been detected up to the maximum tested concentration of 5 mg of sodium N-methyltaurinate per plate.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Read across from N-Methyltaurine

Qualifier:

according to guideline

Guideline:

other: not specified

Principles of method if other than guideline:

The results and data from the testing of 255 chemicals for mutagenicity in Salmonella are presented. All chemicals were tested under code using a preincubation modification of the Salmonellal microsome test in the absence of exogenous metabolic activation and in the presence of liver S-9 from Aroclor-induced male Sprague-Dawley rats and Syrian hamsters.

The purpose of this report is to present the results and data from the testing of 255 chemicals for their ability to induce mutations in Salmonella. Because some chemicals were tested in more than one laboratory or at different times within the same laboratory, a total of 291 individual samples were tested. All testing was performed at Case Western Reserve University (CWR; Dr. W. Speck), EG&G Mason Research Institute (EGG; Dr. S. Haworth [later Microbiological Associates, Inc.; MIC]), and SRI International (SRI; Dr. K. Mortelmans). The substance N-Methyltaurine was tested at SRI.

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Supplier: Crescent Chemical
Testing Lab: SRI International

Target gene:

his

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Metabolic activation system:

Metabolic activation was performed using S-9 fractions of Aroclor 1254-induced, male Sprague-Dawley rat and male Syrian hamster livers.

Test concentrations with justification for top dose:

Dose: 100-10000 µg/plate

At least five doses of the chemical were tested in triplicate. Experiments were repeated at least 1 wk following the initial trial. Each chemical was tested initially at half-log doses up to a dose that elicited toxicity; subsequent trials occasionally used narrower dose increments. Chemicals that were not toxic were tested to a maximum dose of 10 mg/plate. Chemicals that were poorly soluble were tested up to a dose defined by their solubility. A maximum of 0.05 ml solvent was added to each plate.

Vehicle / solvent:

Solvent: Distilled water

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

9-aminoacridine

sodium azide

other: 4-nitro-o-phenylenediamine (Strain: TA98)

Remarks:

The positive control for metabolic activation was 2-aminoanthracene for all strains.

Evaluation criteria:

An individual trial was judged mutagenic, if a dose-related increase over the corresponding solvent control was seen. A chemical was judged to be mutagenic, if it produced a reproducible, dose-related increase in his+ revertants over the corresponding solvent controls in replicate trials.

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Key result

Species / strain:

S. typhimurium TA 100

Remarks:

Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 100

Remarks:

Metabolic Activation: Hamster, Liver, S-9, Aroclor 1254 (10%); Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 100

Remarks:

Metabolic Activation: Rat, Liver, S-9, Aroclor 1254 (10%); Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 1535

Remarks:

Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 1535

Remarks:

Metabolic Activation: Hamster, Liver, S-9, Aroclor 1254 (10%); Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 1535

Remarks:

Metabolic Activation: Rat, Liver, S-9, Aroclor 1254 (10%); Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 1537

Remarks:

Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 1537

Remarks:

Metabolic Activation: Hamster, Liver, S-9, Aroclor 1254 (10%); Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 1537

Remarks:

Metabolic Activation: Rat, Liver, S-9, Aroclor 1254 (10%); Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 98

Remarks:

Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 98

Remarks:

Metabolic Activation: Hamster, Liver, S-9, Aroclor 1254 (10%); Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 98

Remarks:

Metabolic Activation: Rat, Liver, S-9, Aroclor 1254 (10%); Method: Preincubation; Dose: 100-10000 µg/plate (test material solvent: distilled water)

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Conclusions:

The genetic toxicity of N-methyltaurine was tested in a bacterial reverse mutation assay (Ames test). Concentrations of up to 10 mg N-methyltaurine per plate were tested. N-methyltaurine does not exhibit genetic toxicity on S. typhimurium strains TA 100, TA 1535, TA 1537 and TA 98 in the presence or absence of metabolic activation using S-9 fractions of Aroclor 1254-induced, male Sprague-Dawley rat and male Syrian hamster livers.

Executive summary:

The publication reports the results of a bacterial reverse mutation assay (Ames test) from the testing of 255 chemicals, including N-methyltaurine, for mutagenicity in various Salmonella typhimurium strains with and without metabolic activation. Metabolic activation was performed with liver S-9 mixes from Aroclor 1254-induced male Sprague-Dawley rats and Syrian hamsters, respectively. Concentrations of up to 10 mg N-methyltaurine per plate were tested. N-methyltaurine does not exhibit genetic toxicity on S. typhimurium strains TA 100, TA 1535, TA 1537 and TA 98 in the presence or absence of metabolic activation.

N-methyltaurinate is the deprotonated form of N-methyltaurine. Both sodium N-methyltaurinate and N-methyltaurine are highly soluble in water. Hence, it is expected that both substances behave similarly in aqueous solution. Therefore, the experimental data on N-methyltaurine provide a reasonable measure for the genetic toxicity of sodium N-methyltaurinate. Hence, we conclude that sodium N-methyltaurinate has no mutagenic effects.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

The publication by Zeiger et al. reports the results of a bacterial reverse mutation assay (Ames test) from the testing of 255 chemicals, including N-methyltaurine, for mutagenicity in various Salmonella typhimurium strains with and without metabolic activation. Metabolic activation was performed with liver S-9 mixes from Aroclor 1254-induced male Sprague-Dawley rats and Syrian hamsters, respectively. Concentrations of up to 10 mg of N-methyltaurine per plate were tested. N-methyltaurine does not exhibit genetic toxicity on S. typhimurium strains TA 100, TA 1535, TA 1537 and TA 98 in the presence or absence of metabolic activation. N-methyltaurinate is the deprotonated form of N-methyltaurine. Both sodium N-methyltaurinate and N-methyltaurine are highly soluble in water. Therefore, it is expected that both substances behave similarly in aqueous solution. Hence, the experimental data on N-methyltaurine provide a reasonable measure for the genetic toxicity of sodium N-methyltaurinate.

This result is supported by the OECD 471 guideline study on sodium N-methyltaurinate, where no genetic toxicity has been detected up to the maximum tested concentration of 5 mg of sodium N-methyltaurinate per plate.

Conclusively, sodium N-methyltaurinate has no mutagenic effects and does not need to be classified.

Justification for classification or non-classification

According to the bacterial reverse mutation studies on N-methyltaurine and sodium N-methyltaurinate using various strains of Salmonella typhimurium and various concentrations, both test substances do not exhibit genetic toxicity. N-methyltaurinate is the deprotonated form of N-methyltaurine. Both sodium N-methyltaurinate and N-methyltaurine are highly soluble in water. Therefore, it is expected that both substances behave similarly in aqueous solution. Hence, the experimental data on N-methyltaurine provide a reasonable measure for the genetic toxicity of sodium N-methyltaurinate. Therefore, we conclude that sodium N-methyltaurinate has no mutagenic effects and does not need to be classified.