2-ethoxybenzoic acid

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

data is from peer reviewed journals

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, Basketter DA.

Year:

2005

Bibliographic source:

Dermatitis, 2005 Dec; 16(4):157-202

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

The skin sensitizing potential of the test chemical was assessed by using the Mouse Local Lymphnode Assay.

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Salicylic acid

EC Number:

200-712-3

EC Name:

Salicylic acid

Cas Number:

69-72-7

Molecular formula:

C7H6O3

IUPAC Name:

salicylic acid

Test material form:

solid

Details on test material:

- Name of test material (as cited in study report):Salicylic acid
- Molecular formula :C7H6O3
- Molecular weight :138.1214 g/mol
- Substance type:organic
- Physical state:solid

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
Source: No data
Age at study initiation: 7-12 weeks

ENVIRONMENTAL CONDITIONS: No data

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

25 µl

No. of animals per dose:

no data available

Details on study design:

no data available

Positive control substance(s):

not specified

Statistics:

no data available

Results and discussion

Positive control results:

no data available

In vivo (LLNA)

Results

Parameter:

EC3

Value:

0

Test group / Remarks:

test group

Remarks on result:

other: not sensitizing

Cellular proliferation data / Observations:

The relative potency index of the test chemical was not calculates since the SI were less than 3

Any other information on results incl. tables

Table 2: Results of the LLNA study

Vehicle

LLNA%

LLNA%

LLNA%

LLNA%

LLNA%

LLNA SI

LLNA SI

LLNA SI

LLNA SI

LLNA SI

LLNA EC3

Relative Potency

AOO

5

10

25

-

-

0.8

1.5

2.5

0

0

NC

Non sensitizer

Where AOO – Acetic acid in olive oil(4:1) ; SI - Stimulation Index; NC – Not calculated

 

Applicant's summary and conclusion

Interpretation of results:

other: not sensitizing

Conclusions:

The relative potency index of the test chemical was not calculated since the SI were less than 3.
Based on the relative potency, the test chemical was considered to be not sensitizing to mice skin.

Executive summary:

The skin sensitizing potential of the test chemical was assessed by using the Mouse Local Lymphnode Assay. The study was conducted as per OECD 429 Guidelines.

The LLNA was conducted on groups of CBA mice (7-12 weeks of age) by mean of topical application of chemical on the dorsum of both ears at a dose of 25µl or to an equal volume of relevant vehicle (Acetic acid in olive oil (4:1))only. Treatment was performed daily for 3 consecutive days. Five days after initiation of exposure all mice were injected via the tail vein with 250µl of PBS containing 20µCi of tritiatied thymidine. The mice were sacrificed 5 hours later, and draining the auricular lymph nodes were excised and pooled for each experimental group or each individual animal. The incorporation of tritiated thymidine measured by β-scintillation counting and was reported in disintegrations /minute. An SI was calculated for each chemical group as the ratio of disintegrations/minute of the treated group to the disintegrations/minute of the concurrent vehicle control group.

A substance was classified skin sensitizer, if at one or more than one concentrations, it induced a three-fold or greater increase in local lymph node proliferative activity when treated with the concurrent vehicle treated controls (SI ≥3) The approach to estimation of the relative skin sensitization potential is based on the mathematical estimation of the concentration of chemical necessary to obtain a threshold positive response (SI = 3); this is termed as the EC3 value.

The relative potency index of the test chemical was not calculated since the SI were less than 3.

Based on the relative potency, the test chemical was considered to be not sensitizing to mice skin.