Tetramethylammonium hydroxide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Limited experimental details available.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Tetramethylammonium hydroxide

EC Number:

200-882-9

EC Name:

Tetramethylammonium hydroxide

Cas Number:

75-59-2

Molecular formula:

C4H12N.HO

IUPAC Name:

N,N,N-trimethylmethanaminium hydroxide

Details on test material:

- Name of test material (as cited in study report): TMAH
- Lot No.: 81021A

Method

Target gene:

- S. typhimurium: Histidine gene
- E. coli: Tryptophan gene

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

Without S-9 mix:
39.1, 78.1, 156, 313, 625 and 1250 ug/plate (S. typhimurium TA98, TA100, TA1535, TA1537, E. coli WP2 uvrA)
With S-9 mix:
39.1, 78.1, 156, 313, 625 and 1250 ug/plate (S. typhimurium TA98, TA100, TA1535, TA1537); 39.1, 78.1, 156, 313, 625, 1250, 2500, and 5000 ug/plate (E. coli WP2 uvrA)

Vehicle / solvent:

water

Controls

Controls 1

Negative solvent / vehicle controls:

yes

Remarks:

water

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

Without S9-mix: 0.5 ug/plate (TA1535); 2-(2-Furyl)-3-(5-nitro-2-furyl) acrylamide, 0.01 ug/plate (TA100, WP2), 0.1 ug/plate (TA98); 9-Aminoacridine hydrochloride, 80 ug/plate (TA1537).

Controls 2

Negative solvent / vehicle controls:

yes

Positive control substance:

other: 2-Aminoanthracene at 1 ug/plate (TA100), 2 ug/plate (TA1535 and TA1537), 10 ug/plate (WP2) or 0.5 ug/plate (TA98).

Details on test system and experimental conditions:

The test was conducted by the preincubation method and triplicate plates were used for each of six different concentrations of the test substance.

Evaluation criteria:

The test substance was considered positive in mutagenicity if the number of revertants found was more than twice the number of those of the solvent (water) control and if reproducible or concentration-dependent increase in the number of the revertants were observed.

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 1250 ug/plate and above

Vehicle controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative

In an AMES test conducted according to OECD guideline 471 and GLP principles, TMAH was found to be negative for mutagenicity, with or without metabolic activation.

Executive summary:

An AMES test was conducted according to OECD guideline 471 and GLP principles. Considerable growth inhibition was observed in all strains treated at the highest concentrations of tetramethylammonium hydroxide. However, no increase in the number of revertant colonies was observed in either strain (S. typhimurium TA98, TA100, TA1535, TA1537, or E.coli WP2 uvrA) treated at any concentrations of tetramethylammonium hydroxide with or without metabolic activation (S9 mix). These results have led to the conclusion that tetramethylammonium hydroxide is negative for mutagenicity in the bacterial reverse mutation assay (Ames test) regardless of metabolic activation.