Prometryn

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 Jul 1987 to 24 Aug 1987

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

no TA 102 or E.coli WP2 tested

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Prometryn

EC Number:

230-711-3

EC Name:

Prometryn

Cas Number:

7287-19-6

Molecular formula:

C10H19N5S

IUPAC Name:

6-(methylsulfanyl)-N2,N4-di(propan-2-yl)-1,3,5-triazine-2,4-diamine

Test material form:

solid: particulate/powder

Method

Target gene:

his-locus

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

Type and composition of metabolic activation system:
- source of S9: Aroclor 1254 induced rat liver
- concentration or volume of S9 mix and S9 in the final culture medium : 0.3 mL

Test concentrations with justification for top dose:

20, 78, 313, 1250 and 5000 µg/ 0.1 mL

Vehicle / solvent:

- Solvent used: acetone

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

sodium azide

cyclophosphamide

other: daunorubicin-HCl (D-HCl), 9(5)-aminoacridine hydrochloride monohydrate (9-AHM), 2-aminoanthracene (2-AA)

Details on test system and experimental conditions:

PRELIMINARY TOXICITY TEST
A preliminary toxicity test is carried out with strain TA 100 without activation with the concentrations ranging from 0.08 to 5000 ug/0.1 mL. The protocol used is the same as in the main test.

NUMBER OF REPLICATIONS:
- Number of cultures per concentration: 3 petri dishes
- Number of independent experiments : 1

METHOD OF TREATMENT/ EXPOSURE:
- Test substance added in agar (plate incorporation)

TREATMENT AND HARVEST SCHEDULE:
- Exposure duration/duration of treatment: 48 hours at 37 °C

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method, e.g.: background growth inhibition

Evaluation criteria:

CRITERIA FOR A POSITIVE RESPONSE
The test substance is considered to be positive in this test system if one or both of the following conditions are met:
- at least a reproducible doubling of the mean number of revertants per plate above that of the negative control at any concentration level for one or more of the following strains: TA 98, TA 1535 and TA 1537,
- a reproducible increase of the mean number of revertants per plate for any concentration above that of the negative control by at least a factor of 1.5 for strain TA 100.
Generally a concentration-related effect should be demonstrable.

ASSAY ACCEPTANCE CRITERIA
A test is considered acceptable if the mean colony counts of the control values of all strains are within the acceptable ranges and if the results of the positive controls meet the criteria for a positive response

Results and discussion

Test results

Key result

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TOXICITY TEST
Nine concentrations of the test material, ranging from 0.08 to 5000 µg/0.1 mL were tested to determine the highest concentration to be used in the mutagenicity assay. From the results obtained, the highest concentration suitable for the mutagenicity tests was found to be 5000 µg/0.1 mL.

TEST-SPECIFIC CONFOUNDING FACTORS
At the concentrations of 1250 and 5000 µg/0.1 mL the substance precipitated in soft agar.

Applicant's summary and conclusion

Conclusions:

Under the conditions in the study (OECD 471, GLP), no evidence of the induction of point mutations by the test material, or by the metabolites of the substance formed as a result of microsomal activation was detectable in the strains of S. typhimurium used in these experiments.

Executive summary:

In a GLP compliant study performed according to OECD guideline 471 the test material was tested for mutagenic effects on histidine-auxotrophic mutants of Salmonella typhimurium. The investigations were performed on strains TA 98, TA 100, TA 1535 and TA 1537 without and with microsomal activation at the following concentrations: 20, 78, 313, 1250 and 5000 µg/0.1 mL. In order to confirm the results, the experiments were repeated. 

The test material in solution was analysed to confirm the intended concentrations to be used in the mutagenicity tests. The measured concentrations were in agreement with the nominal test concentrations. In the experiments performed without and with microsomal activation, none of the tested concentrations of the test material led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control. No signs of bacterial toxicity or precipitation were evident in the study.

No evidence of the induction of point mutations by the test material, or by the metabolites of the substance formed as a result of microsomal activation was detectable in the strains of S. typhimurium used in these experiments. The substance was found to be non-mutagenic in this study.