5-Isothiazolecarboxamide, 3,4-dichloro-N-(2-cyanophenyl)-

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

Study period:

01 Mar 2005 - 10 Oct 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3,4-dichloro-N-(2-cyanophenyl)-1,2-thiazole-5-carboxamide

EC Number:

619-682-1

Cas Number:

224049-04-1

Molecular formula:

C11H5Cl2N3OS

IUPAC Name:

3,4-dichloro-N-(2-cyanophenyl)-1,2-thiazole-5-carboxamide

Constituent 2

Reference substance name:

3,4-dichloro-2'-cyano-1,2-thiazole-5-carboxanilide

IUPAC Name:

3,4-dichloro-2'-cyano-1,2-thiazole-5-carboxanilide

Method

Species / strain

Species / strain / cell type:

S. typhimurium, other: all strains

Metabolic activation:

with and without

Metabolic activation system:

S9 (male Wistar rats induced with 500 mg/kg bw Aroclor 1254 5 days prior to sacrifice

Test concentrations with justification for top dose:

0, 16, 50, 158, 500, 1581 and 5000 ug/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification: the test substance is sufficiently soluble in the vehicle

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Without S9-mix: sodium azide, mitomycin C, cumene hydroperoxide, nitrofurantoin, 4-Nitro-1,2-phenylene diamine; with S9-mix: 2-Aminoanthracene

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION

Plate incorporation test:
- Exposure duration: 48 hrs

Preincubation test:
- Preincubation period: 20 min
- Exposure duration: 48 hrs

NUMBER OF REPLICATIONS: Two tests, each using three plates per strain per dose


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth by colony count

Evaluation criteria:

A reproducible and dose-related increase in mutant counts of at least one strain is considered to be a positive result. For TA 1535, TA 100 and TA 98 this increase should be about twice that of negative controls, whereas for TA1537, at least a threefold increase should be reached. For TA 102 an increase of about 100 mutants should be reached. Otherwise, the result is evaluated as negative. However, these guidelines may be overruled by good scientific judgment.

Results and discussion

Test results

Species / strain:

S. typhimurium, other: all strains

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Remarks:

Substance precipitation started at 1581 µg/plate, but assessment was deemed possible up to 5000 µg/plate.

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: At 1581 ug/plate and above the substance precipitated. Evaluation was still possible up to and including 5000 ug/plate.

RANGE-FINDING/SCREENING STUDIES: The data from the range-finding study was used as there was no cytotoxicity up to the limit value of 5000 ug/plate and the precipitation did not affect the results. No additional study was performed.

COMPARISON WITH HISTORICAL CONTROL DATA: No "untreated" negative control was set up for the used solvent, since sufficient evidence was available in the literature (e.g. Maron and Ames, 1983) and from historical data.

ADDITIONAL INFORMATION ON CYTOTOXICITY: No cytotoxicity was observed up to the maximum dose of 5000 ug/plate

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table: Maximum number of revertants (means) of all concentrations tested (one result per strain, with the plate concentration between brackets):

	Control		Test substance (µg/plate)
Strain	-S9	+S9	-S9	+S9
TA 1535	11	12	11 (5000)	12 (500)
TA100	155	193	166 (16)	200 (16)
TA1537	6	10	5 (50)	8 (16)
TA 98	19	34	22 (50)	36 (16)
TA 102	214	250	238 (50)	273 (158)

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative