Sodium 4-propoxycarbonylphenoxide

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:

guideline study with acceptable restrictions

Remarks:

No data about GLP.

Data source

Reference

Reference Type:

publication

Title:

COMPARISON OF THE LOCAL LYMPH NODE ASSAY WITH THE GUINEA-PIG MAXIMIZATION TEST FOR THE DETECTION OF A RANGE OF CONTACT ALLERGENS

Author:

Basketter, D.A. and Scholes, E.W.

Year:

1992

Bibliographic source:

Fd Chem Toxic. Vol. 30, No. 1, pp. 65-69

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Propyl 4-hydroxybenzoate

EC Number:

202-307-7

EC Name:

Propyl 4-hydroxybenzoate

Cas Number:

94-13-3

Molecular formula:

C10H12O3

IUPAC Name:

propyl 4-hydroxybenzoate

Details on test material:

- Name of test material (as cited in study report): Propyl paraben
- Analytical purity: > 98%

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/Ca

Sex:

not specified

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: 8 -12 weeks

Study design: in vivo (LLNA)

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

5, 10 and 25%

No. of animals per dose:

4

Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: A chemical was regarded as a sensitizer in the LLNA if at least one concentration of the chemical resulted in a three-fold or greater increase in ³HTdR incorporation compared to the control values. Also the data had to be compatible with a biological dose response although an allowance was made, especially at high doses, for either local toxicity or immunological suppression.

TREATMENT PREPARATION AND ADMINISTRATION:
Groups of 4 mice were treated by a daily topical application of 25 µL of each test substance concentration on the dorsal surface of each ear for 3 consecutive days. The negative control group was treated with vehicle only. Four days after the first topical application, all mice were injected intraveniously through the tail vein with 20 µCi [³H]methyl thymidine (³HTdR) in 250 µL phosphate buffered saline (PBS). After 5 h, the mice were killed by carbon dioxide asphyxiation and the draining auricular lymph nodes were excised and pooled for each group. A single cell suspension of lymph node cells was prepared. ³HTdR incorporation was measured by β-scintillation counting.

Positive control substance(s):

mercaptobenzothiazole (CAS No 149-30-4)

Results and discussion

Positive control results:

Stimulation Index:
10% positive control substance: 4.5
25% positive control substance: 4.6
50% positive control substance: 5.5

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

1.3

Test group / Remarks:

5% test substance

Results 2

Key result

Parameter:

SI

Value:

1.6

Test group / Remarks:

10% test substance

Results 3

Key result

Parameter:

SI

Value:

1.3

Test group / Remarks:

25% test substance

Applicant's summary and conclusion

Interpretation of results:

other: CLP/EU GHS criteria not met, no classification required according to Regulation (EC) No 1272/2008

Conclusions:

The available data on propyl 4-hydroxybenzoate did not show any skin sensitising effects. Therefore, the test substance is not predicted to be a skin sensitiser.

Executive summary:

The skin sensitising potential of propyl 4-hydroxybenzoate was investigated in a Local Lymph Node Assay (LLNA) in mice according to OECD Guideline 429 (Basketter, 1992). Four CBA/Ca mice per test group were treated with the test substance at concentrations of 5, 10 and 25% in acetone/olive oil (4:1 v/v) or with vehicle alone for three consecutive days by open application on the ears (25 µL/ear). Three days after the last exposure, all animals were injected with 3H-methyl thymidine and approximately after five hours the draining (auricular) lymph nodes were excised and pooled for each test group. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed. Treatment with test substance concentrations of 5, 10 and 25% resulted in SI values of 1.3, 1.6 and 1.3, respectively. No EC3 value was calculated. The reliability check with positive control mercaptobenzothiazole indicated that the LLNA is an appropriate model for testing for contact hypersensitivity. Based on the results, the test substance was not regarded as a skin sensitiser under the conditions of the test.