Registration Dossier

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1995.12.8-1997.7.8
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study was according to OECD guide lines and was performed under GLP.

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Unnamed
Year:
1997
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)
Deviations:
no
Principles of method if other than guideline:
Guidelines for screening Mutagenicity testing of Chemicals (Japan) and OECD Test Guideline 471 and 472
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 1,3-isobenzofurandione, tetrahydromethyl (THMBF)
- Analytical purity: 99.97%
- Lot/batch No.: 2522
- Stability under test conditions: stable, purity 99.13% after testing
- Storage condition of test material: sealed, room temperature, dark place
- Molecular formula (if other than submission substance): C9 H10 O3
- Molecular weight (if other than submission substance): 166.18
- Smiles notation (if other than submission substance): O=C(OC(=O)C1CC=C(C2)C)C12
- InChl (if other than submission substance): 1/C9H10O3/c1-5-2-3-6-7(4-5)9(11)12-8(6)10/h2,6-7H,3-4H2,1H3
- Structural formula attached as image file (if other than submission substance): see Fig. (11070-44-3 structure.png)

Method

Target gene:
not indicated
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
- Type and identity of media: provided by Dr. A. N. Ames, California University, USA on 1975-10-31
- Properly maintained: yes, -80 °C
- Periodically checked for Mycoplasma contamination: yes
- Periodically checked for karyotype stability: yes
- Periodically "cleansed" against high spontaneous background: yes
Additional strain / cell type characteristics:
not applicable
Species / strain / cell type:
E. coli WP2 uvr A
Details on mammalian cell type (if applicable):
- Type and identity of media: provided by Dr.Gada, National Institute of Genetics, Japan on 1979-5-9
- Properly maintained: yes, -80 °C
- Periodically checked for Mycoplasma contamination: yes
- Periodically checked for karyotype stability: yes
- Periodically "cleansed" against high spontaneous background: yes
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9 mix
Test concentrations with justification for top dose:
-S9 mix; 0, 62.5, 125, 250, 500, 1000, 2000 ug/plate
+S9 mix; 0, 156, 313, 625, 1250, 2500, 5000 ug/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: well-known solvent for general purpose
Details on test system and experimental conditions:
Type: Ames test
METHOD OF APPLICATION: in medium; in agar (plate incorporation); preincubation; in suspension; as impregnation on paper disk


DURATION
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS:2

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; other: The test substance is considered to be positive for mutagenic activity when assay plates with the test substance show a significant increase in revertant colony count as compared with that on negative control plates and when this effect is reasonably reproducible or dose dependent.
Evaluation criteria:
no details given
Statistics:
no details given

Results and discussion

Test results
Species / strain:
other: Salmonella typhimurium, TA100, TA1535, TA98, TA1537, Escherichia coli Wp2 uvrA
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: without metabolic activation(-S9mix)| 500 ug/plate (TA1535),| 1000 ug/plate (TA100, TA98, TA1537),| 2500 ug/plate (WP2)|with metabolic activation(+S9mix)| 5000 ug/plate (TA100, TA1537)
Vehicle controls validity:
valid
Untreated negative controls validity:
not valid
Positive controls validity:
valid
Additional information on results:
This chemical did not induce mutations in the S. typhimurium and E. coli strains.

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: 7.4
Remarks on result:
other:
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

no remarks

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Tetrahydromethylphthalic anhydride (MTHPA) was not mutagenic in Salmonella typhimuriumTA100, TA1535, TA98, TA1537 and Escherichia coli WP2uvrA at concentrations up to 5 mg/plate or 2 mg/plate, with or without an exogenous metabolic activation system, respectively.
Executive summary:

In a reverse gene mutation assay in bacteria, strains TA100, TA1535, TA98, TA1537 of S. typhimurium and Escherichia coli Wp2 uvrA were exposed to tetrahydromethylphthalic anhydride in DMSO at concentrations of 0, 62.5, 125, 250, 500, 1000, 2000 ug/plate (-S9 mix) and 0, 156, 313, 625, 1250, 2500, 5000 ug/plate (+S9 mix) in the presence and absence of mammalian metabolic activation (S9 mix, Rat liver, induced with Phenobarbital and 5,6-benzoflavone).

Tetrahydromethylphthalic anhydride was tested up to limit concentration (5000 µg/plate). No cytotoxicity occurred. The test chemical did not induce mutations in the S. typhimurium and E. coli strains The positive controls induced the appropriate responses in the corresponding strains. There was no evidence of induced mutant colonies over background.

This study is classified as acceptable. This study satisfies the requirement for the Japanese Guidelines for Screening Mutagenicity Testing Of Chemicals Test Guideline and OECD 471 and 472 for in vitro mutagenicity (bacterial reverse gene mutation) data.