Bis(methylcyclohexyl) phthalate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

May 26, 1983

Deviations:

yes

Remarks:

compared to current guideline, no e.coli strain or Salmonella TA 102 tested

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Bis(methylcyclohexyl) phthalate

EC Number:

248-765-1

EC Name:

Bis(methylcyclohexyl) phthalate

Cas Number:

27987-25-3

Molecular formula:

C22H30O4

IUPAC Name:

bis(1-methylcyclohexyl) phthalate

Test material form:

liquid: viscous

Details on test material:

1,2-benzenedicarbonic acid, bis-(methylcyclohexyl)-ester (CAS: 27987-25-3)

Method

Species / strain

Species / strain / cell type:

other: S. typhimurium TA 1538, TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Metabolic activation system:

S9 mix (rat liver)

Test concentrations with justification for top dose:

8, 40, 200, 1000 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Tween 80 and bidest. water
Edenol 344 was suspended in Tween 80 (ratio of Edenol 344 : Tween 80, 1:1 (w/w)), heated to approx. 60°C and adjusted with warm bidist. water (approx. 60°C) to the desired highest concentration. The suspension was then cooled down to room temperature and diluted with bidist. water to the desired concentrations just before the start of the test. Homogeneity was maintained during preparation of the suspension and dissolving until application, using a shaker for test-tubes or a magnetic stirrer.

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

9-aminoacridine

sodium azide

other: 4-nitro-o-phenylendiamine

Details on test system and experimental conditions:

10 ml of a sterile 0.5mM-histidine-0.5 mM-biotine solution per 100 ml Top Agar were mixed. 2 ml of this soft Top Agar were filled into sterile test tubes. 0.1 ml of the tester strain suspension and 0.1 ml of the test substance solution were added per tube.
In both test series without S9-mix, 5 concentrations of the test substance Edenol 344 were filled into the respective test tubes. Instead of the S9-mix, 0.5 ml of buffer was added to the test batches. After mixing, the test batch was poured out onto the minimal agar plates. In both test series with S9-mix 5 concentrations of the test substance Edenol 344 were filled into the respective test tubes. Then 0.5 ml S9-mix was added to the test batch, mixed carefully and poured out onto the minimal agar plates within approx. 30 seconds.
After hardening of this layer, the plates were incubated upside down for 48 hours at 37°C centigrade. The colonies were counted with a BioTran-III-Counter (Biotronik). For each tester strain, the results were reported as revertants per plate. For comparison the values of the positive controls and of the negative controls were reported, too. The figures reported for Edenol 344 are the mean values and the individual values for the three parallel batches and of the test substance concentrations.

Evaluation criteria:

A combination of the following criteria was considered as a positive result:
- The plate background of non-reverted bacteria did not show any growth reduction versus the respective negative controls.
- The spontaneous mutation rates of each tester strain per plate were within the characteristic spontaneous mutation range.

Results and discussion

Test results

Key result

Species / strain:

S. typhimurium, other: TA 98, TA 100, TA 1535, TA 1537 and TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Remarks:

partial reduction of background lawn at 5000µg/plate

Untreated negative controls validity:

valid

Positive controls validity:

valid