Registration Dossier

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
March - April 1979
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non GLP; non guideline; minor restrictions in design but adequate for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
no
Remarks:
performed before GLP
Type of study:
guinea pig maximisation test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous
Details on test material:
clear viscous liquid

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
Female albino guinea pigs (Dunkin-Hartley)
bw: 300 - 400 g
Housing: 5 per cage
standard diet of guinea pig pellets and tap water, ad libitum

in life phase: 16. March to 8. April 1979

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
water
Concentration / amount:
Induction
- intradermal: 1% (w/w)
- topical: 5% (w/w) in water
challenge: 2% (w/w) in water
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
Induction
- intradermal: 1% (w/w)
- topical: 5% (w/w) in water
challenge: 2% (w/w) in water
No. of animals per dose:
treated group: 10
control group: 5
Details on study design:
RANGE FINDING TESTS: 2 guinea pigs which were pre-treated with adjuvant only at the induction phase, test substance was applied at concentrations of 10, 5, 2 and 1%. A concentration of 2% was selected as the level to be used at the challenge stage.

MAIN STUDY
A. INDUCTION EXPOSURE
treated group: 3 injections: a) 0.1 ml Freund's adjuvant alone; b) 0.1 ml 2-ethylhexoic acid (1% w/w) alone; c) 0.05 ml 2-ethylhexoic acid (1% w/w) emulsified with 0.05 ml Freund's adjuvant; 6 days after the injection phase: treatment with sodium lauryl sulphate solution (10 % w/w), after 24 h: patch of Whatman No. 3 MM filter paper saturated with 2-ethylhexoic acid (5% w/w) covered by an overlapping patch of impermeable plastlc adhesive tape for48 h
control group: injection with Freund's adjuvant alone

B. CHALLENGE EXPOSURE
treated and control group: two weeks after the topical induction: 2-ethylhexoic acid (2% w/w) was applied on a 2 x 2 cm piece of filter paper to the test site of the guinea pig. The patch was held in place for the topical induction and removed 24 h Iater.

The degree of response was determined by trained assessors 24 h after removal of the challenge patch. Positive response are rated
according to the percentage of animals sensitised (Kligman).
Positive control substance(s):
no

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
2% w/w
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: test group. Dose level: 2% w/w. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no data.
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
2% w/w
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
no data
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 2% w/w. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: no data.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
In a guinea pig maximization test 2-ethylhexanoic acid caused no allergic reaction. Therefore, 2-ethylhexanoic acid is not considered to be a skin sensitiser.
Based on a read-across approach, sodium 2-ethylhexanoate is not considered to be a skin sensitizer and is therefore not subjected for labelling and classification requirements according to regulatory requirements.
Executive summary:

A read across was performed from the source substance 2 -ethylhexanoic acid to the target substance sodium 2 -ethylhexanoate (for read across justification please refer to attached document, IUCLID Chapter 13).

Testing for sensitising properties of 2 -ethylhexanoic acid was performed in female guinea pigs according to the Guinea Pig Maximization Test. Intradermal induction was performed using 1 % 2-ethylhexanoic acid in water and topical induction using 5% 2 -ethylhexanoic acid in water. The challenge was carried out with 2% 2 -ethylhexanoic acid (epidermal) two weeks after topical induction.

2 -Ethylhexanoic acid induced no allergic reactions, and therefore, the test substance is not considered to have sensitising properties.

Based on a read-across approach, sodium 2-ethylhexanoate is not considered to be a skin sensitizer and is therefore not subjected for labelling and classification requirements according to regulatory requirements.