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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
13-02-1990 to 16-03-1990
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD guideline 406 followed to GLP
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Existing study conducted prior to REACH implementation
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Porcellus [formerly Porcellus Animal Breeding Ltd)
- Age at study initiation: 5-9 weeks
- Weight at study initiation: 255-355g
- Housing: The animals were housed initially in single sex groups of ten animals. In the two day period before the study began they were re-allocated to
cages accommodating two or three animals. Hanging galvanised steel cages with wire-mesh floors were used, each measuring 54 cm x 31 cm x 36 cm.
Sawdust-filled trays for excreta were placed beneath each cage and changed twice weekly.
- Diet ad libitum): Pelleted diet (SG1 with vitamin C supplement. Grain Harvesters Ltd.)
- Water ad libitum
- Acclimation period: two weeks before any experimentation commenced

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19' to 23 degrees C
- Humidity (%): 30-70%
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): 12 hour day and 12 hour night.

Route:
intradermal and epicutaneous
Vehicle:
corn oil
Concentration / amount:
Intradermal induction: 0.2% (m/v) in corn oil/FCA
Topical induction: 10% (m/v) in corn oil
Topical Challenge: 0.5% (m/v) in corn oil
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
Intradermal induction: 0.2% (m/v) in corn oil/FCA
Topical induction: 10% (m/v) in corn oil
Topical Challenge: 0.5% (m/v) in corn oil
No. of animals per dose:
n = 10 males; n = 10 females (test groups)
n = 5 males; n= 5 females (control groups)
Details on study design:
RANGE FINDING IRRITATION TESTS: n =2 males; n = 2 females.
0.1 ml doses of several dilutions (60, 25, 10, 3, 1, 0.5, 0.3%) of the test material were injected lntradermally on each side of the mid-line.
The animals were examined on the following day to determine the maximum concentration that caused no more than moderate
irritation. 0.2% was selected for use in the intradermal phase of induction.

Further groups of two male and two female guinea·pigs were treated with 0.3 ml doses of several dilutions of the
test material absorbed onto 16 cm2 Whatman No. 3 filter paper patches. The patches were applied tn skin on the shorn flanks, covered by occlusive
tape, and retained by an elastic adhesive bandage for 24 hours. After removal of the patches and bandages the dermal test sites were examined for
signs of irritation which were scored using a four point scale. The concentration selected for topical induction in the main test was
the highest level that caused no more than moderate irritation. The concentration selected for challenge (10% m/v) was the maximum that was
non-irritant.

MAIN STUDY
A. INDUCTION EXPOSURE
Two rows of intradermal injections were made, one on either side of the mid-line, as follows:
Test animals:
Anterior sites - 0.1 ml of Freunds Complete Adjuvant (FCA)
Middle sites - 0.1 ml of test material in vehicle
Posterior sites - 0.1 ml of test material in 50:50 FCA/vehicle

Control animals:
Anterior sites - 0.1 m1 of FCA
Middle sites - 0.1 ml of vehicle
Posterior sites - 0.1 ml of 50:50 FCA/vehicle

One week after induction by intradermal injection, the same area of dorsal skin was shaven using eleccric clippers only.
A 16 cm^2 patch of Whatman No. 3 filter paper was moistened with 0.3 ml of the appropriately diluted test material and placed over the
sites of intradermal injections. The patches were covered with occlusive tape and held in place by elastic adhesive bandage for 48 hours.
Similar patches of filter paper moistened with the vehicle alone were applied to the control group guinea-pigs. Any abnormal reactions to
the induction procedure were recorded.

B. CHALLENGE EXPOSURE
Challenge was carried out three weeks after the intradermal phase of induction. Hair was removed from one flank of all test and control animals
by clipping and shaving. A 4 cm^2 patch of Whatman No. 3 filter paper, moistened witll 0.1 ml of the appropriate dilution of test material, was
placed on the shaven area, covered by occlusive tape and held in position by elastic adhesive bandage. Control group animals were treated with the
same formulation of test material that was applied to test group animals. After 24 hours the patches and bandages were removed and the challenge
sites examined for any response.
Positive control substance(s):
no
Positive control results:
None
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
10% induction, 0.5% challenge dose
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
None
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: 10% induction, 0.5% challenge dose. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: None.

No test animals showed any signs of sensitisation reactions to o-tert butylphenol in the main study.

Interpretation of results:
GHS criteria not met
Conclusions:
Under the conditions of this study, no animals showed signs of sensitisation following induction and challenge with o-tert butyl phenol.
Executive summary:

In an OECD guideline 406 Magnusson Kligman guinea-pig maximisation test, n =10 male and n = 10 female Dunkin-Hartley guinea-pigs were induced intradermally with 0.2% O-tert butylphenol in corn oil and epicutanously with a concentration of 10% m/v OTBP in corn oil. Following challenge with 0.5% m/v o-tert butyl phenol in corn oil, no animals showed signs of skin sensitisation.

It is concluded that o-tert butyl phenol is not a skin sensitiser.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

In an OECD guideline 406 Magnusson Kligman guinea-pig maximisation test, n =10 male and n = 10 female Dunkin-Hartley guinea-pigs were induced intradermally with 0.2% o-tert butylphenol in corn oil and epicutanously with a concentration of 10% m/v OTBP in corn oil. Following challenge with 0.5% m/v o-tert butyl phenol in corn oil, no animals showed signs of skin sensitisation.

In a supporting guinea-pig maximisation test conducted in 1981 not to GLP, o-tert butyl phenol was also found not be sensitising.

It is concluded that o-tert butyl phenol is not a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

O-tert butyl phenol did not show any signs of sensitisation in an OECD guideline 406 guinea-pig maximisation test.

O-tert butyl phenol is not sensitising