Ethyl 1,3-dihydro-1,3-dioxo-2H-isoindole-2-carboxylate

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:

28-Mar-2016 to 14-Apr-2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

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

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl 1,3-dihydro-1,3-dioxo-2H-isoindole-2-carboxylate

EC Number:

245-048-5

EC Name:

Ethyl 1,3-dihydro-1,3-dioxo-2H-isoindole-2-carboxylate

Cas Number:

22509-74-6

Molecular formula:

C11H9NO4

IUPAC Name:

ethyl 1,3-dioxo-2,3-dihydro-1H-isoindole-2-carboxylate

Test material form:

solid

Details on test material:

- Appearance: white solid
- Storage conditions of test material: in refrigerator (2-8°C)

Method

Target gene:

- S. typhimurium: Histidine gene
- E. coli: Tryptophan gene

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S9-mix induced by Aroclor 1254

Test concentrations with justification for top dose:

Experiment 1 (direct plate assay)
Preliminary test (without and with S9) TA100 and WP2uvrA: 1.7, 5.4, 17, 52, 164, 512, 1600 and 5000 µg/plate
Main study: TA1535, TA1537 and TA98:
Without and with S9-mix: 52, 164, 512, 1600 and 5000 µg/plate
Experiment 2 (pre-incubation assay):
Without and with S9-mix: 17, 52, 164, 512, 1600 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle:
Test compound was stable in DMSO and DMSO has been accepted and approved by authorities and international guidelines

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Remarks:

without S9: 650 µg/plate in DMSO for TA100

Controls 2

Positive control substance:

2-nitrofluorene

Remarks:

without S9: 10 µg/plate in DMSO for TA98

Controls 3

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

without S9: 10 µg/plate in DMSO for WP2uvrA

Controls 4

Positive control substance:

sodium azide

Remarks:

without S9: 5 µg/plate in saline for TA1535

Controls 5

Positive control substance:

other: ICR-191

Remarks:

without S9: 25 µg/plate in DMSOfor TA1537

Controls 6

Positive control substance:

other: 2-aminoanthracene in DMSO for all tester strains

Remarks:

with S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: plate incorporation and pre-incubation methods

DURATION
- Exposure duration: 48 hour

NUMBER OF REPLICATIONS:
- Doses of the test substance were tested in triplicate in each strain. Two independent experiments were conducted.

NUMBER OF CELLS EVALUATED: 10E8 per plate

DETERMINATION OF CYTOTOXICITY
- Method: The reduction of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies.

OTHER EXAMINATIONS:
- The presence of precipitation of the test compound on the plates was determined.

Evaluation criteria:

A test substance is considered negative (not mutagenic) in the test if:
a) The total number of revertants in tester strain TA100 or WP2uvrA is not greater than two (2) times the concurrent control, and the total number of revertants in tester strains TA1535, TA1537 or TA98 is not greater than three (3) times the concurrent control.
b) The negative response should be reproducible in at least one independently repeated experiment.

A test substance is considered positive if:
a) A two-fold (TA100, WP2uvrA) or more or a three-fold (TA1535, TA1537, TA98) or more increase above solvent control in the mean number of revertant colonies is observed in the test substance group.
b) In case a repeat experiment is performed when a positive response is observed in one of the tester strains, the positive response should be reproducible in at least one independently repeated experiment.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No precipitation was observed up to and including the top dose of 5000 µg/plate

RANGE-FINDING/SCREENING STUDIES:
- Cytotoxicity, as evidenced by a decrease in the number of revertants and/or a reduction in the bacterial background lawn, was observed in tester strains
TA100, TA1535 and TA1537 in the absence and presence of S9-mix and in strain TA98 in the absence of S9-mix.

COMPARISON WITH HISTORICAL CONTROL DATA:
- The negative and strain-specific positive control values were within our laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
Pre-incubation assay:
TA1535: without and with S9: 1600 µg/plate and above
TA1537: without and with S9: 1600 µg/plate and above
TA98: without and with S9: 1600 µg/plate and above
TA100: without and with S9: 1600 µg/plate and above
WP2uvrA: without S9: 5000 µg/plateand with S9: 1600 µg/plate and above

Applicant's summary and conclusion

Conclusions:

It is concluded that Carbaethoxyphthalimid is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.

Executive summary:

Carbaethoxyphthalimid did not induce a significant dose-related increase in the number of revertant (His⁺) colonies in each of the four tester strains (TA1535, TA1537, TA98 and TA100) and in the number of revertant (Trp⁺) colonies in tester strain WP₂uvrA both in the absence and presence of S9-metabolic activation. These results were confirmed in an independently repeated experiment.

In this study, acceptable responses were obtained for the negative and strain-specific positive control items indicating that the test conditions were adequate and that the metabolic activation system functioned properly.