Methylammonium chloride

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:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from peer reviewed publication

Data source

Reference

Reference Type:

publication

Title:

Mutagenicity of N,N’-dimethylurea and methylamine hydrochloride in the Ames Salmonella/microsome test: absence of mutagenic response

Author:

G.P. Meshram, R. Padma Maiini and Kola M. Rao

Year:

1992

Bibliographic source:

Mutation Research. 279 (l992) 275-280

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: as per mentioned below

Principles of method if other than guideline:

Gene mutation toxicity study was performed to determine the mutagenic nature of Methylamine hydrochloride (MAH)

GLP compliance:

no

Type of assay:

bacterial gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Methylammonium chloride

EC Number:

209-795-0

EC Name:

Methylammonium chloride

Cas Number:

593-51-1

Molecular formula:

CH5N.ClH

IUPAC Name:

methanamine

Constituent 2

Reference substance name:

Methylamine hydrochloride

IUPAC Name:

Methylamine hydrochloride

Details on test material:

Details on test material
- Name of test material (as cited in study report): MAH (Methylamine hydrochloride)
- Molecular formula (if other than submission substance): CH5N.Cl H
- Molecular weight (if other than submission substance): 67.5184 g/mol
- Substance type: Organic
- Physical state:
Purity-98%
- Impurities (identity and concentrations): 2%

Specific details on test material used for the study:

- Name of test material: Methylamine hydrochloride (MAH)
- IUPAC name: Methanaminium chloride
- Molecular formula: CH5NCl H
- Molecular weight: 67.5184 g/mol
- Substance type: Organic
- Physical state: No data
- Purity-98%
- Impurities (identity and concentrations): 2%

Method

Target gene:

Histidine

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA98, TA100 and TA104

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

other: Histidine-deficient (His-) mutants

Cytokinesis block (if used):

No data

Metabolic activation:

with and without

Metabolic activation system:

S9 fraction was prepared from Aroclor 125-l-pretreated male Wistar rats

Test concentrations with justification for top dose:

0, 0.08, 0.8, 1.6, 16.0, 32.0, 64.0 mg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: The chemical was soluble in DMSO

Controls

Untreated negative controls:

yes

Remarks:

DMSO

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

other: 2-aminofiuorene (All strains; With S9); 2,4,7-Trinitro-9.fluorenone (TA98; Without S9); Methylglyoxal (TA104; WIth S9)

Details on test system and experimental conditions:

METHOD OF APPLICATION: Liquid preicubation assay

DURATION
- Preincubation period: 12 hour
- Exposure duration: 30 min
- Expression time (cells in growth medium): - Selection time (if incubation with a selection agent):
- Fixation time (start of exposure up to fixation or harvest of cells): 48 hour
METHOD OF APPLICATION: Liquid preincubation assay
- Cell density at seeding (if applicable): No data

DURATION
- Preincubation period: 30 mins
- Exposure duration: 48 hrs
- Expression time (cells in growth medium): 48 hrs
- Selection time (if incubation with a selection agent): No data
- Fixation time (start of exposure up to fixation or harvest of cells): No data

SELECTION AGENT (mutation assays): No data

SPINDLE INHIBITOR (cytogenetic assays): No data

STAIN (for cytogenetic assays): No data

NUMBER OF REPLICATIONS: Duplicate

METHODS OF SLIDE PREPARATION AND STAINING TECHNIQUE USED: No data

NUMBER OF CELLS EVALUATED: No data

NUMBER OF METAPHASE SPREADS ANALYSED PER DOSE (if in vitro cytogenicity study in mammalian cells): No data

CRITERIA FOR MICRONUCLEUS IDENTIFICATION: No data

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; other: Yes, number of surviving cells were counted
- Any supplementary information relevant to cytotoxicity: No data

OTHER EXAMINATIONS:
- Determination of polyploidy: No data
- Determination of endoreplication: No data
- Methods, such as kinetochore antibody binding, to characterize whether micronuclei contain whole or fragmented chromosomes (if applicable): No data

- OTHER: No data

Rationale for test conditions:

No data

Evaluation criteria:

Each plate was examined under the microscope for the presence of background lawn (His-, auxotrophs). The mutagenic response was considered to be positive if the mean number of His’ revertant colonies obtained was double the negative (solvent) control at any dose, either in the presence or in the absence of S9 mix.

Statistics:

Mean ± SD

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA98, TA100 and TA104

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

At 64 mg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks:

Positive mutagens used resulted in a strongly positive mutagenic response by inducing a multiple-fold increase in the number of His’ revertant colonies over the negative control.

Additional information on results:

No data

Applicant's summary and conclusion

Conclusions:

Methylamine hydrochloride (MAH) failed to induce gene mutation in Salmonella typhimurium strain TA98, TA100 and TA104 both in the presence and absence of S9 metabolic activation system and hence is not likely to classify as a gene mutant in vitro.

Executive summary:

Gene mutation toxicity study was performed to determine the mutagenic nature of Methylamine hydrochloride (MAH; IUPAC name: Methanaminium chloride). Liquid preicubation assay was performed using Salmonella typhimurium strain TA98, TA100 and TA104 in the presence and absence of 5%, 15% and 30% S9 metabolic activation system. The test chemical dissolved in DMSO was used at dose levels of 0, 0.08, 0.8, 1.6, 16.0, 32.0 or 64.0 mg/plate. Duplicate plates were set at each dose level. DMSO was used as negative control and concurrent positive control chemicals were also included in the study. The mutagenic response was considered to be positive if the mean number of His- revertant colonies obtained was double the negative (solvent) control at any dose, either in the presence or in the absence of S9 mix. MAH at the highest dose of 64 mg/plate was toxic, reducing the surviving cells in comparison to DMSO. Positive mutagens used in the present study resulted in a strongly positive mutagenic response by inducing a multiple-fold increase in the number of His- revertant colonies over the negative control. Methylamine hydrochloride (MAH) failed to induce gene mutation in Salmonella typhimurium strain TA98, TA100 and TA104 both in the presence and absence of S9 metabolic activation system and hence is not likely to classify as a gene mutant in vitro.