Sodium cumenesulphonate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

not specified

Type of assay:

other: Mouse micronucleus cytogenetic assay

Test material

Test material information

Constituent 1

Reference substance name:

Sodium cumenesulphonate

EC Number:

248-983-7

EC Name:

Sodium cumenesulphonate

Cas Number:

28348-53-0

Molecular formula:

C9H12O3S.Na

IUPAC Name:

sodium cumenesulphonate

Test material form:

solid

Specific details on test material used for the study:

CAS Number: 28348-53-0
Identity: Cumene sulfonic acid, sodium salt
Purity: 99.4%
Remarks: 40% solution in water

Test animals

Species:

mouse

Strain:

NMRI

Details on species / strain selection:

Species: Mouse , 24-30 g.
Strain: NMRI
Sex: Male/female
No. of animals 5 per sex per dose group per sample time

Sex:

male/female

Details on test animals or test system and environmental conditions:

Strain NMRI. Animals were approximately 24-30 g and acclimated for 1 week to the test conditions (20 =/- 3 degrees C, 30-70% relative humidity, 12 hour light/dark cycle).

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: no data
- Concentration of test material in vehicle: 40 %
- Amount of vehicle: 16.8 ml/kg bw

Details on exposure:

Single oral dose at 0 and 4467 mg/kg bw; vehicle water, dose volume 17 ml/kg bw. Dose selection was based on preliminary studies with 2-5/sex: no
deaths at and below 4467 mg/kg bw ( one incidental death (female) at 3981 mg/kg bw), 4/10 deaths at 5000 mg/kg bw.

Duration of treatment / exposure:

72 hours

Frequency of treatment:

single oral application

Post exposure period:

24, 48 and 72 hours

Doses / concentrations

Remarks:

Doses / Concentrations:
4467 mg/kg bw
Basis: actual ingested

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Positive control(s):

cyclophosphamide
- Justification for choice of positive control(s): no data
- Route of administration: oral by gavage
- Dose: 100 mg/kg bw
- Vehicle: water
- Total application volume: 10 ml/kg bw
- post exposure period: 24 hours

Examinations

Tissues and cell types examined:

bone marrow; polychromatic erythrocytes (PCE), normochromatic erythrocytes (NCE)

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: The maximum tolerable dose (MTD)* was selected as dose.

The MTD was determined in a dose range finding study :
Phase 1: Limit test with 5000 mg/kg bw
Phase 2: Determination of the TMTD range with reduced animal number
Phase 3: Determination of the MTD with 5 animals/sex/dose

*MTD is defined as dose with no mortality but clear clinical symptoms within 3 days after application

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):
24, 48 and 72 hours after treatment the animals were killed by cervical dislocation and tissue was sampled.

DETAILS OF SLIDE PREPARATION:
The femora were removed and the bone marrow was suspended in fetal calf serum. The cell suspensions were centrifuged with 160 x g for 5 minutes and the supernatand discarded. The serum was resuspended and the suspension purified using a cellulose chromatographic column. The eluate was centrifuged at 800 x g for 10 minutes and the pellet in fetal calf serum /25 mM EDTA suspended. From this suspension 3-4 smears per animals were prepared on slides which were dried for at least 24 hours and stained with May-Grünwald/Giemsa solution.

METHOD OF ANALYSIS:
The cell analysis was performed by means of a Zeiss miscroscope at a 1000fold magnification (oil immersion). At least 1000 polychromatic erythrocytes (PCE) per animal were examined to determine the frequency of micronucleated cells. The ratio of PCE to normochromatic cells (NCO) was determined for a sample of 1000 erythrocytes. The number of micronucleated cells in counted NCE was determined.

Evaluation criteria:

For the identification of micronuclei the following criteria were considered:
a) roundish and clear contour by the nuclear membrane
b) diameter of about 1/20 of the size of the polychromatic erythrocyte
c) lays in the same focus layer as the observed erythrocyte

The micronucleus test is regarded as positive (test substance induces micronuclei in polychromatic erythrocytes) if the frequency of mucronucleated polychromatic erythrocytes of at least one tretament group is statistically significantly increased compared to the negative control and the increase is biologically relevant.

Statistics:

Mean values and standard deviations were calculated for the following parameters:
a) number of polychromatic erythrocytes (PCE) containing micronuclei
b) ratio of PCE/NCE

Comparison of treatment groups with different post exposure periods with negative controls of respective post exposure periods. After control of the relative frequency of micronuclei in the treatment groups on homogeneity with the mean relative frequency a statistical analysis of micronucleus frequency using a 2 x 2 contingency table with chi² test and continuity table according to Yates was performed (see [1]).
The differences of miconucleus frequencies in the positive control were reassessed in the two-sided t-test. This test was also used for the statistical analysis of the PCE/NCE-ratio.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

Sodium cumenesulphonate under these test conditions is regarded as not mutagenic in the micronucleus test.

Applicant's summary and conclusion

Conclusions:

Interpretation of results : negative
All male mice treated with the test substance showed no statistically significant increase in micronucleus frequency at any sampling time compared to control animals. For the female mice treated with the test substance at sampling times 24 and 48 hours after treatment also no statistically significant increase in micronucleus frequency was observed. Only at sampling time point 72 hours a statistically significant increase of polychromatic erythrocytes with micronuclei compared to control animals was observed. This effect was regarded as biologically not relevant as this increase ís based on the exceptional low micronucleus frequency of vehicle control group.
Sodium cumenesulphonate under these test conditions is regarded as not mutagenic in the micronucleus test.

Executive summary:

Interpretation of results : negative

All male mice treated with the test substance showed no statistically significant increase in micronucleus frequency at any sampling time compared to control animals. For the female mice treated with the test substance at sampling times 24 and 48 hours after treatment also no statistically significant increase in micronucleus frequency was observed. Only at sampling time point 72 hours a statistically significant increase of polychromatic erythrocytes with micronuclei compared to control animals was observed. This effect was regarded as biologically not relevant as this increase ís based on the exceptional low micronucleus frequency of vehicle control group.

Sodium cumenesulphonate under these test conditions is regarded as not mutagenic in the micronucleus test.