1,2,4-Oxadiazol-5(2H)-one, 3-(4-aminophenyl)-

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study in accordance to guideline requirements. Non GLP-Study but sufficiently documented.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Principles of method if other than guideline:

The test substance was investigated in a modified bacterial reverse mutation test as described by Ames et al. (1975). The traditional Salmonella
microsome mutation assay (Ames test) is used extensively as a routine test for mutagenicity for more than 25 years. The high throughput
microtitre-based version, called Ames II, is based on the same genetic principle (base-pair substitution and frameshift mutations in the his operon
of S. typhimurium) as the traditional Ames test but combined with the fluctuation method (Gee et al., 1998). Because of its high concordance (80%)
compared with the standard assay, the Ames II procedure seems an effective screen for identifying bacterial mutagens (Flueckiger et al., 2004).
Due to its explorative character and the lack of regulatory acceptance these data are, however, intended for supporting use only.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

3-(4-aminophenyl)-2,5-dihydro-1,2,4-oxadiazol-5-one

EC Number:

917-912-8

Cas Number:

864680-71-7

Molecular formula:

C8 H7 N3 O2

IUPAC Name:

3-(4-aminophenyl)-2,5-dihydro-1,2,4-oxadiazol-5-one

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium, other: TA Mix (TA 7001, TA 7002, TA 7003, TA 7004, TA 7005 and TA 7006)

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 98

Metabolic activation:

with and without

Metabolic activation system:

S9 (Aroclor 1254)

Test concentrations with justification for top dose:

1-5000 µg/Plate

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

2-nitrofluorene

other: 2-Aminoanthracen (2-AA)

Evaluation criteria:

The pH indicator bromocresol purple turns the colour of the cultures from blue to yellow as the pH drops due to the accumulation of catabolites
from the metabolic activity of revertant cells. The number of positive wells (yellow) out of a total of 48 wells is an indication of the frequency of
reversion per replicate per dose and was compared to the number of spontaneous revertant wells of the solvent control. Each test point contains
48 wells of a 384-well plate. In each 48-well section, the wells were scored for the number of revertant wells (yellow) and the mean value of the
triplicates was calculated.

The experiment is regarded valid, if the vehicle control showed the normal spontaneous revertant frequency and the diagnostic mutagens caused
the expected increase in the mutation rate. The individual test chemicals were classified according to the following criteria:
Negative: ≤8/48 wells Equivocal: 9-12/48 wells Positive: ≥13/48 wells
Historical control range: 0-7/48 wells in ca 220 experiments (1999-up to date)
A concentration-dependent increase of revertant wells (mean of triplicate) over the vehicle control is indicative for a genotoxic activity of the test substance.

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA Mix (TA 7001, TA 7002, TA 7003, TA 7004, TA 7005 and TA 7006)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at the top concentration tested.

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):
negative with metabolic activation
negative without metabolic activation

Based on the described results it is concluded, that BIBR 1048 Oxa-Amin, when tested up to bacteriotoxic concentrations, caused neither
base-pair substitutions nor frameshift mutations in bacteria. No evidence of genotoxic activity was observed in a series of S. typhimurium tester
strains (TA Mix and TA 98) in the absence and presence of metabolic activation. The test article is, therefore, classified as "Ames II negative".