2H-Tetrazol-5-amine, N-2H-tetrazol-5-yl-, ammonium salt (1:1)

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-03-07 - 2008-05-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an internationally accepted guideline. All study parameters are based on the specific guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

485-280-6

EC Name:

-

Cas Number:

303749-96-4

Molecular formula:

Hill formula: C2H6N10 CAS formula: C2H3N9.H3N

IUPAC Name:

N-(1H-1,2,3,4-tetrazol-5-yl)-1H-1,2,3,4-tetrazol-5-amine amine

Constituent 2

Reference substance name:

-

EC Number:

482-280-8

EC Name:

-

IUPAC Name:

482-280-8

Constituent 3

Reference substance name:

1H-Tetrazol-5-amine-, N-1H-tetrazol-5-yl-, monoammonium salt

IUPAC Name:

1H-Tetrazol-5-amine-, N-1H-tetrazol-5-yl-, monoammonium salt

Method

Species / strain

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Details on mammalian cell type (if applicable):

clone V79/D3

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

53.4, 106.9, 213.8, 427.5 , 855.0, 1710.0 microgramm per ml

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

Results and discussion

Test results

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
positive

1-H-Tetrazol-5amine-, N-1H-tetrazol-5-yl-, monoammonium salt was tested in the invitro mammalian chromosome aberration test according to OECD Guideline 473.
Under the experimental conditions reported, the test item 1-H-Tetrazol-5amine-, N-1H-tetrazol-5-yl-, monoammonium salt induced structural chromosome aberrations in V79 cells (Chinese hamster cell line) in the absence and presence of S9 mix.

Executive summary:

The test item 1-H-Tetrazol-5amine-, N-1H-tetrazol-5-yl-, monoammonium salt, suspended in deionised water, was assessed for its potential to induce structural chromosome aberrations in V79 cells of the Chinese hamster in vitro in the absence and the presence of metabolic activation by S9 mix. According to the OECD Guideline only one experiment was performed, since the test item was considered to be mutagenic after 4 hours treatment. The chromosomes were prepared 18 hours after start of treatment with the test item. The exposure period was 4 hours with and without metabolic activation. In each experimental group two parallel cultures were set up. Per culture at least 100 metaphases were scored for structural chromosome aberrations. In a range finding pre-test on toxicity cell numbers were scored 24 hours after start of treatment as an indicator for cytotoxicity. Concentrations between 13.4 and 1710 µg/mL were applied. Clear toxic effects were observed after 4 hours treatment with 1710 µg/mL in the absence and presence of S9 mix. In the pre-experiment, neither precipitation nor relevant influence of the test item on the osmolarity was observed (solvent control 286 mOsm versus 311 mOsm at 1710 µg/mL). Due to a slight pH shift observed the top concentrations 427.5 to 1710 pg/mL were adjusted with 2 M NaOH to physiological values (solvent control pH 7.4 versus pH 7.0 at 1710 µg/mL). In the main experiment the pH values of the three highest test item concentrations (427.5 to 1710 µg/mL) were adjusted with 2 M NaOH to physiological values (pH 7.0 at 1710 µg/mL). In the main experiment no precipitation of the test item in culture medium was observed either with or without S9 mix. In the absence of S9 mix cytotoxicity indicated by reduced cell numbers (49.0 % and 55.9 % of control) was observed after treatment with 855 and 1710 pg/mL. In the presence of S9 mix strong cytotoxicity indicated by reduced mitotic indices (40.8 % of control) was observed at the highest evaluated concentration (427.5 µg/mL). In the absence of S9 mix a dose-related increase in the number of aberrant cells excluding gaps (4.5 %, 11.0 %, and 14.5 %, respectively) were observed after treatment with 427.5, 855, and 1710 µg/mL. The values at the two highest evaluated concentrations were statistically significant increased and all values exceeded the laboratory's historical control data range (0.0 - 4.0 % aberrant cells excluding gaps). In addition, in the presence of S9 mix the number of aberrant cells excluding gaps (2.8 %, 3.0 %, and 20.5 %) increased in a dose-related manner. The value (20.5 % aberrant cells excluding gaps) at the highest evaluated concentration (427.5 pg/mL) clearly exceeded the laboratory's historical control data range (0.0 - 4.0 % aberrant cells excluding gaps). Therefore, 1-H-Tetrazol-5amine-, N-1H-tetrazol-5-yl-, monoammonium salt has to be regarded as clastogenic. Table 4, page 27, shows the occurrence of polyploid metaphases. No biologically relevant increase in the rate of polyploid metaphases was found after treatment with the test item (2.2 - 3.6 %) as compared to the rates of the solvent controls (2.4 - 2.8 %). Either EMS (900 µg/mL) or CPA (1.4 µg/mL) were used as positive controls and showed distinct increases in the number of cells with structural chromosome aberrations.

In conclusion, it can be stated that under the experimental conditions reported, the test item 1-H-Tetrazol-5amine-, N-1H-tetrazol-5-yl-, monoammonium salt induced structural chromosome aberrations in V79 cells (Chinese hamster cell line) in the absence and presence of S9 mix.