(3S,6S,7R,8R)-8-Benzyl-3-{[(3-hydroxy-4-methoxypyridin-2-yl)carbonyl]amino}-6-methyl-4,9-dioxo-1,5-dioxonan-7-yl 2-methylpropanoate

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other:

Version / remarks:

Japanese Ministry of Agriculture, Forestry and Fisheries. Testing Guidelines for Toxicology Studies,
2000. Notification No. 12-Nousan-8147. November 24, 2000. Reverse Mutation Studies 2-1-19-1.

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(3S,6S,7R,8R)-8-benzyl-3-(3-hydroxy-4-methoxypyridine-2-amido)-6-methyl-4,9-dioxo-1,5-dioxonan-7-yl 2-methylpropanoate

Cas Number:

167173-85-5

Molecular formula:

C26H30N2O9

IUPAC Name:

(3S,6S,7R,8R)-8-benzyl-3-(3-hydroxy-4-methoxypyridine-2-amido)-6-methyl-4,9-dioxo-1,5-dioxonan-7-yl 2-methylpropanoate

Specific details on test material used for the study:

Substance name: X642188
Batch #: SYN-FS08353-048
Purity: 99%

Method

Target gene:

Genes coding for histidine and tryptophan biosynthetic enzymes

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

Rat liver homogenate activation system (S9 Mix)

Test concentrations with justification for top dose:

156.25, 312.5, 625, 1250, 2500 and 5000 μg/plate

Vehicle / solvent:

Dimethyl sulfoxide (DMSO)

Controls

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

2-nitrofluorene

sodium azide

mitomycin C

other: 2-aminoanthracene, 9-Aminoacridine hydrochloride hydrate

Results and discussion

Test results

Key result

Species / strain:

other: TA1537, TA1535, TA98, TA100 and TA102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Negative bacterial reverse mutation assay in S. typhimurium TA1537, TA1535, TA98, TA100 and TA102

Executive summary:

This study was performed to evaluate mutagenic activity of X642188 by the bacterial reverse mutation test using five histidine deficient (his-) mutant tester strains of Salmonella typhimurium viz., TA1537, TA1535, TA98, TA100 and TA102. The methods followed were compliant with the OECD 471 (1997), OPPTS 870.5100 (1998), EEC B.13/14 (2008) and JMAFF 2-1-19-1 (2000) test guidelines.

The treatments were performed by the plate incorporation technique both in the absence and presence of metabolic activation (S9 mix). The S9 mix (5% and 10% v/v) consisted of an S9 fraction (Aroclor 1254 - induced rat liver homogenate) supplemented with cofactors.

In a cytotoxicity test, inhibition of bacterial lawn and/or reduction in the number of revertant colonies was not observed up to the test guidelines limit dose of 5000 μg X642188/plate both in the absence and presence of the metabolic activation system (5% v/v S9 mix).

Based on the results of the cytotoxicity test, the concentrations of 156.25, 312.5, 625, 1250, 2500 and 5000 μg/plate of X642188 both in the absence and presence (5% v/v S9 mix) of metabolic activation were selected for Trial I. Trial I did not show positive mutagenic response when compared to the negative control at any of the tested concentrations. Trial II was conducted to confirm the negative results of Trial I with concentrations separated by 2.5-fold i.e., 51.2, 128, 320, 800, 2000 and 5000 μg X642188/plate both in the absence and presence of metabolic activation (S9 concentration was increased to 10% v/v). A positive mutagenic response was not observed even in Trial II, confirming the results of Trial I. The efficiency of the test system was demonstrated by a clear increase in revertant colonies observed with the positive controls both in the absence and presence of metabolic activation.

From the results of this study, under the specified experimental conditions, X642188 is concluded to be non-mutagenic in the bacterial reverse mutation assay using Salmonella typhimurium.