.beta.-Alanine, N-[3-amino-4-(methylamino)benzoyl]-N-2-pyridinyl-, ethyl ester

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:

02 Dec - 18 Dec 1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

1.Because the first experiment showed slightly increased revertant counts in S. typhimurium TA98(in the presence of S9 mix) following BIBR 1048/CDBA 122 BS exposure, the experiment was repeated with and without S9 mix. 2.The frameshift strainTA included

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

ethyl 3-{1-[3-amino-4-(methylamino)phenyl]-N-(pyridin-2-yl)formamido}propanoate

EC Number:

606-728-0

Cas Number:

212322-56-0

Molecular formula:

C18 H22 N4 O3

IUPAC Name:

ethyl 3-{1-[3-amino-4-(methylamino)phenyl]-N-(pyridin-2-yl)formamido}propanoate

Test material form:

solid: particulate/powder

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Additional strain / cell type characteristics:

other: TA 1538

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

Based on the results of the pretest, BIBR 1048/CDBA 122 BS was tested in triplicate over a concentration range of 100 to 5000 ug/plate. No precipitation of the test article in the soft agar was seen. There was a slight strain-specific bacteriotoxicity as seen by a reduced background lawn and/or a decrease of absolute revertants at the top concentration (TA 98, nonactivation).

Vehicle / solvent:

DMSO

Controls

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

mitomycin C

other:

Details on test system and experimental conditions:

Storage conditions at room temperature in the dark (ambient humidity)

Rationale for test conditions:

All control values were within the historical range of our laboratory.
Metabolic activation by hepatic microsomal enzymes from rats did not alter the mutation frequency of most bacterial strains. In the strain TA 98 there was a slight nominal increase of mutants (2 fold) with metabolic activation at the top concentration. Though the value was within the historical control range, the increase could be confirmed in the repeat experiment, qualitatively. At the top concentration the number of mutants exceeded the historical control range experienced in our laboratory.

Evaluation criteria:

A reproducible, concentration-dependent increase in the number of revertants of at least one tester strain over the vehicle control value and/or outside the historical control range is indicative of genotoxic activity. To confirm the sensitivity of the tester strains and the metabolic capacity of the S9 fractions known diagnostic mutagens were used (2-NF, NaN3,9-AA,MMC, 2-AA). Results showed the BIBR 1048 /CDBA 122 BS did not increase the number of revertants in S. Typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102 compared to the negative control.

Statistics:

Individual plate counts were recorded separately and the mean of the plate counts for each treatment were determined. Control counts were compared with the laboratory's historical control ranges.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 102

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Species / strain:

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

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Species / strain:

other: TA1535, TA1537, TA100, TA102

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Based on the results it is concluded, that BIBR 1048/CDBA 122 BS, when tested up to maximally concentrations, caused neither base-pair substitution nor frameshift mutations in bacteria in the nonactivation system. In the presence of metabolic activation BIBR 1048/CDBA 122 BS induced slightly increased revertants in S. typhimurium TA 98. The effect was reproducible. Overall, the test compound is, therefore, classified as equivocal "Ames positive".