Guanidine, N-phenyl-, compd. with carbonic acid, hydrate (2:1:2)

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Oct 2016 - Apr 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test using the Hprt and xprt genes)

Version / remarks:

2016

GLP compliance:

yes

Type of assay:

in vitro mammalian cell gene mutation test using the Hprt and xprt genes

Test material

Test material information

Constituent 1

Reference substance name:

(N-phenylcarbamimidoyl)ammonium carbonate

EC Number:

613-106-2

Cas Number:

6291-89-0

IUPAC Name:

(N-phenylcarbamimidoyl)ammonium carbonate

Method

Target gene:

HPRT

Species / strain

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Metabolic activation system:

phenobarbital and ß-naphthoflavone induced rat liver S9 mix

Test concentrations with justification for top dose:

650.0 - 1600.0 µg/mL
The maximum concentration was chosen with respect to the current OECD Guideline 476 (2016) and a correction factor of 1.3 was used to correct for purity and the ratio of phenylguanidine to carbonate counter ion in the test substance.

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Remarks:

solvent control

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

7,12-dimethylbenzanthracene

ethylmethanesulphonate

Evaluation criteria:

A test chemical is considered to be clearly positive if, in any of the experimental conditions examined all of the following criteria are met:
a) at least one of the test concentrations exhibits a statistically significant increase compared with the concurrent solvent control in both parallel cultures,
b) the increase is concentration-related when evaluated with an appropriate trend test,
c) any of the results are outside the distribution of the historical solvent control data.
When all of these criteria are met, the test chemical is then considered able to induce gene mutations in cultured mammalian cells in this test system.
Providing that all acceptability criteria are fulfilled, a test chemical is considered clearly negative if, in all experimental conditions examined:
a) none of the test concentrations exhibits a statistically significant increase compared with the concurrent negative control,
b) there is no concentration-related increase when evaluated with an appropriate trend test,
c) all results are inside the distribution of the historical negative control data.
The test chemical is then considered unable to induce gene mutations in cultured mammalian cells in this test system.

Statistics:

The statistical analysis was performed in the mean values of culture I and II for all experiments.
A linear regression analysis was performed to assess a possible dose dependency of mutant frequencies.
A t-test was performed using a validated test script of "R", a language and environment for statistical computing and graphics, to evaluate an isolated increase of the mutation frequency at a test point exceeding the 95 % confidence interval and other if necessary.

Results and discussion

Test results

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

True negative controls validity:

not applicable

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

The increases in the mutant frequency observed in the presence of metabolic activation were inconsistent between parallel cultures of the experiments and caused by increases in one culture only. None of those increases in MF were statistically significant increases and there was no relevant dose dependent trend. Based on these results, the test substance meets the criteria for being negative in the HPRT assay.
In conclusion it can be stated that under the experimental conditions reported the test item did not induce gene mutations at the HPRT locus in V79 cells of the Chinese hamster. Therefore, the test substance is considered to be non-mutagenic in this HPRT assay.