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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
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)
Deviations:
not specified
GLP compliance:
no
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Since the LLNA is the preferred method for new in vivo testing, the use of the standard guinea pig tests to obtain new data on the skin sensitisation potential of a substance will be acceptable only in exceptional circumstances and will require scientific justification. However, existing data of good quality that were generated before 10 May 2017, or for which the study was initiated before 10 May 2017, and derived from such tests are acceptable; and if these tests provide clear results that are adequate for classification, even when a conclusion on potency (Cat. 1A or not) cannot be drawn, they will preclude the need for further in vivo testing.

Test material

Reference
Name:
Unnamed
Type:
Constituent

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal and epicutaneous
Vehicle:
water
Challenge
Route:
epicutaneous, occlusive
Vehicle:
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.
Reading:
1st reading
Hours after challenge:
48
Group:
positive control
Remarks on result:
not measured/tested

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Under the conditions tested, the test substance is a non-sensitiser in guinea pigs.