2-methoxy-4-propylphenol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

No data

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

Basic data given but study reported to be performed according to OECD 429 with deviations: purity of test item not reported, number of animals per group, positive controls and body weight not reported; no ear thickness measurement nor excessive irritation assessment. Considered sufficiently reliable in a weight of evidence for the purpose of hazard assessment.

Data source

Reference

Reference Type:

publication

Title:

Compilation of Historical Local Lymph Node Data for Evaluation of Skin Sensitization Alternative Methods

Author:

Gerberick GF, Ryan CA, Kern PS, Schlatter H, Dearman RJ, Kimber I, Patlewicz GY and Basketter DA

Year:

2005

Bibliographic source:

Dermatitis, 16 (4):157-202

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

details on environmental conditions of animal room, number of animals per group, positive controls and body weight not reported; no ear thickness measurement nor excessive irritation assessment

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2-methoxy-4-propylphenol

EC Number:

220-499-0

EC Name:

2-methoxy-4-propylphenol

Cas Number:

2785-87-7

Molecular formula:

C10H14O2

IUPAC Name:

2-methoxy-4-propylphenol

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): Dihydroeugenol
- Purity: No data
- Log Kp: - 2.20
- Log Ko/w: 2.15

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: 7-12 weeks

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

5.1, 10.1 and 25.3 % in 4:1 acetone/olive oil

No. of animals per dose:

No data

Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay
- Criteria used to consider a positive response: A substance was classified as a skin sensitizer if, at one or more test concentrations, it induced a 3-fold or greater increase in local lymph node proliferative activity when compared with concurrent vehicle-treated controls (SI, ≥ 3).

TREATMENT PREPARATION AND ADMINISTRATION:
25 µL of control or test material was applied to the dorsum of both ears daily for three consecutive days. Five days after the initiation of exposure, all animals were injected via the tail vein with 250 µL of phosphate-buffered saline containing 20 µCi of tritiated thymidine. Animals were sacrificed 5 h later and the draining auricular lymph nodes were excised and pooled for each experimental group or each individual animal. The incorporation of tritiated thymidine measured by beta scintillation counting was reported in disintegrations per minute (DPM). Stimulation index (SI) was calculated for each treated group as the ratio of the DPM in the treated group (or mean DPM when individual animals were assessed) to the DPM or mean DPM of the concurrent vehicle control group.

Positive control substance(s):

not specified

Statistics:

No data

Results and discussion

Positive control results:

No data

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

EC3

Value:

6.8

Results 2

Parameter:

SI

Value:

2.7

Test group / Remarks:

5.1%

Results 3

Parameter:

SI

Value:

3.6

Test group / Remarks:

10.1%

Results 4

Parameter:

SI

Value:

7.8

Test group / Remarks:

25.3%

Cellular proliferation data / Observations:

CELLULAR PROLIFERATION DATA
Not reported

DETAILS ON STIMULATION INDEX CALCULATION
Stimulation index for test material at 5.1, 10.1 and 25.3 % were 2.7, 3.6 and 7.8, respectively.

EC3 CALCULATION
Calculated EC3 value for the test material was found to be 6.8 %

CLINICAL OBSERVATIONS:
Not reported

BODY WEIGHTS
Not reported

Applicant's summary and conclusion

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

Under the test conditions, test material is classified as “Category 1B” moderate skin sensitiser according to the annex VI of the Regulation EC No. 1272/2008 (CLP) and to the GHS. Due to the lack of reported details (purity of test item, number of animals per group, positive controls and body weight not reported; no ear thickness measurement nor excessive irritation assessment reported), the study was not used in its own to classify the substance but it was considered sufficiently reliable in a weight of evidence for the purpose of hazard assessment.

Executive summary:

In a Local Lymph Node Assay (LLNA), groups of female CBA mice were topically applied with test material at the dose concentrations of 5.1, 10.1 and 25.3 % final concentration in 1:4 acetone:olive oil to the dorsum of both ears (25 µL/ear) daily for three consecutive days. A vehicle control group was treated with 1:4 acetone:olive oil alone in the same manner. Five days after the initiation of exposure, all animals were injected via the tail vein with 250 µL of phosphate-buffered saline containing 20 µCi of tritiated thymidine. Tritiated thymidine incorporation was quantified using a beta scintillation counter and stimulation index (Sl) was calculated for each dose group.

Stimulation Index (SI Value) calculated for test material treated groups were found to be 2.7, 3.6 and 7.8 for the dose concentrations of 5.1, 10.1 and 25.3 %, respectively. Calculated EC3 value for the test material was found to be 6.8 %.

Under the test conditions, test material is classified as “Category 1B” skin sensitiser according to the annex VI of the Regulation EC No. 1272/2008 (CLP) and to the GHS.

Due to the lack of reported details (purity of test item, number of animals per group, positive controls and body weight not reported; no ear thickness measurement nor excessive irritation assessment reported), the study was not used in its own to classify the substance but it was considered sufficiently reliable in a weight of evidence for the purpose of hazard assessment.