Dimethyl naphthalene-2,6-dicarboxylate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

NDC is considered non mutagenic in bacterial cells (National Institute of Technology and Evaluation, Japan (NITE) 1996), non clastogenic in mammalian CHO cells (MICROBIOLOGICAL ASSOCIATES, INC., 1991) and non mutagenic in mammalian cells (MICROBIOLOGICAL ASSOCIATES, INC., 1990). Additionally the metabolite of NDC (NDA) gave no evidence of chromosomal damage in an in vivo micronucleus study in the mouse.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June to August 1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study run to a detail method and to GLP

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Deviations:

no

Principles of method if other than guideline:

NDC, was tested in the GHO/HGPRT mutation assay in the absence and presence of metabolic activation with Aroclor-induced rat liver S-9. The assay was conducted at dose levels of 1000, 500, 250, 125 and 62.5 μg/mL both in the absence and in the presence of S-9 activation.

GLP compliance:

yes

Type of assay:

mammalian cell gene mutation assay

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

62.5, 125, 250, 500 and 1000 μg/mL

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

ethylmethanesulphonate

Remarks:

in the non-activated study at a final concentration of 0.2 μL/mL

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

in the S-9 activated study at a final concentration of 4 μg/mL

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: 18-24 hours
- Exposure duration: 5 hours

NUMBER OF REPLICATIONS: 2

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency

OTHER EXAMINATIONS:
- Other: expression of the mutant phenotype and selection of the TG-resistant phenotype

No additional data

Evaluation criteria:

None stated

Statistics:

None stated

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES: CHO cells were exposed to solvent alone and to nine concentrations of Dimethyl-2,6-naphthalene dicarboxylate ranging from 1000 to 0.1 µg/mL in the toxicity test in the absence and present of an S-9 reaction mixture. The osmolality of the highest concentration in treatment medium tested, 1000 µg/mL, was 446 mosm/kg, with a measured pH of 7.8. At this dose, the Dimethyl-2,6-naphthalene dicarboxylate was insoluble in solvent and formed a precipitate in treatment medium. Concentrations of 100 to 3 mg/mL were insoluble in solvent. The doses used in the initial assay were 1000, 500, 250, 125 and 62.5µg/mL in the absence and present of S-9. Doses selected for the confirmatory assay were 1000, 500, 250, 125 and 62.5 µg/mL both without and with metabolic activation. All doses were insoluble in treatment medium.

No additional data

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

In a study conducted similar to OECD 476, according to GLP, NDC is negative for gene mutation using Chinese Hamster Ovary (CHO) cells, with and without metabolic activation (S-9 mix). NDC, therefore, is considered non mutagenic in mammalian cells.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

This registration contains a combined approach for addressing the required endpoints. The required endpoints are addressed using, when available, data on the substance to be registered, dimethyl naphthalene-2,6-dicarboxylate (CAS Number 840-65-3) (NDC). When these data are not available, data from the following close structural analogs is used to address the required endpoints. 

 

·        naphthalene-2,6-dicarboxylic acid (CAS number 1141-38-4); and

 

Naphthalene-2,6-dicarboxylic acid is structurally similar to NDC, the registered substance, with a smiles code of c12c(cc(C(O)=O)cc2)ccc(c1)C(O)=O compared to that of c12c(cc(C(OC)=O)cc2)ccc(c1)C(OC)=O of NDC. The additional two methyl groups present in NDC are not expected to cause any significant differences in the toxicological effects of the registered substance nor its degradation products.

 

Naphthalene-2,6-dicarboxylic acid data are used to address the following endpoints:

·        Ames (supporting study); and

·        In vivo genetic toxicity.

In vitro bacterial gene mutation

Key study:

In key studies conducted according to OECD 471 and OECD 472 according to GLP, NDC is negative for bacterial reverse mutation in S. typhimuriumstrains TA 1535, TA 1537, TA 98, and TA 100 and Escherichia coli strain WP2 uvrA, with and without activation (S-9 mix). NDC, therefore, is considered non mutagenic in bacterial cells (Ministry of Health and Welfare, Japan (MHW) 1996)

Supporting study:

In a read across study conducted similar to OECD 471, according to GLP, naphthalene-2,6-dicarboxylic acid (EC Number 214-527-0 and CAS Number 1141-38-4) is negative for bacterial reverse mutation in S. typhimuriumstrains TA 1535, TA 1537, TA 98, and TA 100, with and without activation (S-9 mix). Naphthalene-2,6-dicarboxylic acid, therefore, is considered non mutagenic in bacterial cells (MICROBIOLOGICAL ASSOCIATES, INC., 1990).

 

In vitro chromosome aberration

Key study:

In the key study conducted similar to OECD 473, according to GLP, NDC is negative for chromosome aberrations in Chinese hamster Ovary (CHO) cells, with and without activation (S-9 mix). Although statistically significant increases in structural aberrations were obtained at test concentrations 89.5 and 714 μg/mL in the absence of metabolic S-9 activation, no biological significance was attributed to the observed increases based on the absence of a dose response and the percentage of aberrant cells falling within the historical background limits for the assay. NDC, therefore, is considered non clastogenic in mammalian CHO cells (Microbiological Associates, Inc ., 1991).

 

Supporting study:

In an OECD 473 study, conducted according to GLP, NDC is negative for chromosome aberration in Rat CHl/IU cells, with and without activation (S-9 mix). NDC, therefore, is considered non clastogenic in mammalian cells (Ministry of Health and Welfare, Japan (MHW) 1996).

 

In vitro gene mutation in mammalian cells

In the key study conducted similar to OECD 476, according to GLP, NDC is negative for chromosome aberration using Chinese hamster Ovary (CHO) cells, with and without activation (S-9 mix). NDC, therefore, is considered non mutagenic in mammalian cells (Microbiological Associates, Inc ., 1990).

 

In vivo chromosome aberration

In a read across study conducted similar to OECD 474, according to GLP, naphthalene-2,6-dicarboxylic acid (EC Number 214-527-0 and CAS Number 1141-38-4) did not cause any significant increase in the incidence of micronucleated immature erythrocytes or any substantial decrease in the proportion of immature erythrocyte in male and female mice. Naphthalene-2,6-dicarboxylic acid is therefore considered not to induce chromosome damage or bone marrow cell toxicity in this test system when administered by intraperitoneal injection. (Huntingdon Life Sciences Ltd. 1998).

The following information is taken into account for any hazard / risk assessment:

NDC is considered non mutagenic in bacterial cells (National Institute of Technology and Evaluation, Japan (NITE) 1996), non clastogenic in mammalian CHO cells (Microbiological Associates, Inc ., 1991) and non mutagenic in mammalian cells (Microbiological Associates, Inc ., 1990). Additionally the metabolite of NDC, NDA gave no evidence of chromosomal damage in anin vivomicronucleus study in the mouse.

Justification for selection of genetic toxicity endpoint
in vitro study conducted to guideline similar to OECD 476, according to GLP.

Justification for classification or non-classification

In accordance with Regulation No 1272/2008 Table 3.5.1, based on available data on NDC and the read across substance NDA, NDC is not classified for genotoxicity according to CLP.