Calcium dibenzoate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other:

Remarks:

The test is to a recognised study type, though not conducted to GLP.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: Kimber et al., 1989

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Benzoic acid

EC Number:

200-618-2

EC Name:

Benzoic acid

Cas Number:

65-85-0

Molecular formula:

C7H6O2

IUPAC Name:

Benzoic acid

Test material form:

not specified

Details on test material:

not specified

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Jackson Labs (Bar Harbor, ME) or NCI (Fredrick, MD)
- Age at study initiation: 6 - 9 weeks
- Housing: in compliance with standards set by US Animal Welfare act
- Diet (e.g. ad libitum): in compliance with standards set by US Animal Welfare act
- Water (e.g. ad libitum): in compliance with standards set by US Animal Welfare act

ENVIRONMENTAL CONDITIONS
- Temperature (°C): in compliance with standards set by US Animal Welfare act
- Humidity (%): in compliance with standards set by US Animal Welfare act
- Air changes (per hr): in compliance with standards set by US Animal Welfare act

Study design: in vivo (LLNA)

Vehicle:

other: acetone

Concentration:

5% , 10% and 20%

No. of animals per dose:

5 female animals

Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of the test method: local lymph node assay
- Criteria used to consider a positive response: DPM values are presented for each animal and for each dose group. A Stimulation Index (SI) is calculated for each group. The SI is the ratio of the DPM/group compared to DPM/vehicle group. If the results indicate a SI > 2 (but SI < 30), the test substance may be regarded as a weak to moderate skin sensitiser; if the results indicate a SI > 30, the test substance may be regarded as a strong skin sensitiser, based on the article.

TREATMENT PREPARATION AND ADMINISTRATION:
Groups of five experimental animals were treated with the test substance concentrations of 5%, 10% and 20% on four consecutive days, by open application on both ears (total 25 microliter/ear). Five vehicle control animals were similarly treated, but with vehicle alone (acetone). Eighteen to 24 hours after the last exposure, all animals were injected with 3H-methyl thymidine in phosphate-buffered saline into the tail vein and after five hours the test animals were euthanized and the bilateral auricular lymph nodes were excised. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed.

Positive control substance(s):

not specified

Statistics:

None stated

Results and discussion

Positive control results:

No information provided

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

The SI value for the vehicle control group was 1.0. The SI value for the experimental group treated with test substance concentrations 5% was 0.8. The SI value for the experimental group treated with test substance concentrations 10% was 0.9. The SI value for the experimental group treated with test substance concentrations 20% was 0.8.

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: see Remark

Remarks:

The mean DPM/animal value for the vehicle control group was 5.42E-02 DPM. The mean DPM/animal value for the experimental group treated with test substance concentrations 5% was 4.20E-02 DPM. The mean DPM/animal value for the experimental group treated with test substance concentrations 10% was 5.00E-02 DPM. The mean DPM/animal value for the experimental group treated with test substance concentrations 20% was 4.27E-02 DPM.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The SI values calculated for the test substance concentrations 5%, 10% and 20% were 0.8, 0.9 and 0.8 respectively.
There was no indication that the test substance could elicit an SI >=2 when tested on higher concentrations.
Therefore the test substance does not have to be classified and has no obligatory labeling requirement for sensitization by skin contact.

Executive summary:

This LLNA test was conducted according to a modification of a method described by kimber et al., 1989. Five CBA mice per dose were used.

The SI values calculated for the test substance concentrations 5%, 10% and 20% were 0.8, 0.9 and 0.8 respectively. There was no indication that the test substance could elicit an SI >=2 when tested on higher concentrations. Therefore the test substance does not have to be classified and has no obligatory labeling requirement for sensitization by skin contact.