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Description of key information

Key study: Experimental results: OECD guideline 406. GLP study.
It was concluded that the test substance did not demonstrate delayed contact hypersensitivity in the skin of guinea pigs under this test condition.

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:
From July 7, 1997 to September 4, 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD guideline 406. GLP study.
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
A valid GPMT conducted according to guideline is available, which is reliable without restrictions and adequate for classification and labelling purposes. Potency estimation is not mandatory when existing guideline and GLP conforming data are available, which were conducted before the new annex of the REACH Regulation entered into force. Moreover, no indication for skin sensitisation was observed in this study, thus, no dose response information is needed. For this reason and for reasons of animal welfare no additional LLNA was conducted.
Species:
guinea pig
Strain:
Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: The Clean closed colony from Japan SLC Co. (Kotohcho, Hamamatsu, Shizuoka)
- Age at study initiation: 5 weeks old
- Weight at study initiation: Main study: 334 to 362 g
- Housing: Animals were housed in aluminium cages with stainless steel wire mesh floors (350 mm x 400 mm x 200 mm), 5 animals per cage, which were placed in the cage-rack equipped with an auto-washing system as well as with nozzles for automatic supply of drinking water.
- Diet (e.g. ad libitum): A standard pelleted diet for guinea pigs (RC-4; Oriental Yeast Co.), ad libitum
- Water (e.g. ad libitum): Tap water, ad libitum
- Acclimation period: Five days prior to commencement of the test

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 2 ºC
- Humidity (%): 50 ± 10%
- Air changes (per hr): ventilation rate at 17 times/hour
- Photoperiod (hrs dark / hrs light): lighting from 6.00 to 18.00 o´clock for 12 hours a day.

Route:
intradermal and epicutaneous
Vehicle:
other: physiological saline
Concentration / amount:
Intradermal induction: 1% (w/w) in physiological saline
Topical induction: undiluted
Day(s)/duration:
topical induction 7 d after intradermal; 48 h exposure
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
30%, 10% and 3% (w/w each) in distilled water
Day(s)/duration:
day 21; 24 h exposure
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
Main study: Test group: 10 animals
Details on study design:
RANGE FINDING TESTS:
A preliminary test was performed to assess primary skin irritation using 8 female guinea pigs, and the dose for intradermal injection, topical induction and topical challenge were determined.
- Preparation of test samples for preliminary test
(a) 10%, 3%, 1%, 0.3% (W/W each) of the test substance in physiological saline, and physiological saline alone for intradermal injection.
(b) Undiluted, and 30%, 10%, 3% (W/W each) of the test substance in distilled water for patch.

- Preparation of test samples for induction and challenge
(a) 1:1 (V/V) water-in-oil (w/o) emulsion of FCA (Difco Laboratories, U.S.A.) and physiological saline (Ohtsuka Pharmaceutical Factory, Tokushima)
(b) 1% (W/W) of the test substance in physiological saline
(c) 1:1 (V/V) emulsion of 2% (W/W) test substance in physiological saline and FCA
(d) physiological saline
(e) Undiluted test substance
(f) 30%, 10%, 3% (W/W each) of the test substance in distilled water, and distilled water alone.

MAIN STUDY
A. INDUCTION EXPOSURE
- Exposure period:
Intradermal induction was performed in the shaved skin area of approximately 4cm x 6cm; symmetrically on both sides of the midline in the scapular region, with 0.1 ml each of the 3 test samples (a), (b) and (c) in order from the head part in 10 test animals. Similarly, the samples (a),(d) and again sample (a) were injected to the skin of 5 controls. Seven days later, topical induction was performed using a lint cloth pad (2cm x 4cm), wetted with 0.2 ml of the sample (e), was patched occlusively for 48 hours to the skin sites by double-wrapping with nonpermeable BlendermTM surgical tape and further Silkytex. To the control animals, (d) was patched in the same manner.
- Test groups: one group of 10 females
- Control group: one group of 5 females
- Site: symmetrically on both sides of the midline in the scapular region
- Concentrations:
Intradermal induction: 1% (w/w) in physiological saline
Topical induction: undiluted

B. CHALLENGE EXPOSURE
- Day(s) of challenge: On day 21 after the intradermal induction.
- Exposure period: 24 hours
- Test groups: one group of 10 females
- Control group: one group of 5 females
- Site: The hair on the flank was clipped and the skin was shaves. The circular patches for clinical use whose pad was wetted with 0.1 ml each of the test samples for challenge were tightly fixed to the skin by double-covering with 3 M´s Microform TM soft coverlet and the Silkytex.
- Concentrations: 30%, 10% and 3% (w/w each) in distilled water
- Evaluation (hr after challenge): After removal of the patches, degree of the skin reactions at 24 and 48 hours, respectively, were evaluated.

Positive control substance(s):
yes
Remarks:
(DNCB and formalin)
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
30%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
3%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
30%
No. with + reactions:
0
Total no. in group:
5
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
3%
No. with + reactions:
0
Total no. in group:
5
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
30%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
10%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
3%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
30%
No. with + reactions:
0
Total no. in group:
5
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
10%
No. with + reactions:
0
Total no. in group:
5
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
3%
No. with + reactions:
0
Total no. in group:
5

Throughout the entire period of the test, there were no significant differences in general condition and body weight gain between the test and the control groups.

In all animals of both test and control groups, no significant reaction was observed at challenge sites of the skin at 24 and 48 hours after patch-removal.

Interpretation of results:
GHS criteria not met
Conclusions:
It was concluded that the test substance did not demonstrate delayed contact hypersensitivity in the skin of guinea pigs under this test condition.
Executive summary:

The skin sensitizing potential of the test substance was evaluated by the guinea pig maximization test according to the OECD guideline for testing chemicals (406 Skin Sensitization).

Ten female Hartley albino guinea pigs were exposed to the test substance initially by the intradermal injection of 0.1 ml each of the following samples into the scapular region (intradermal induction); (a) 1:1 (V/V) emulsion of Freund's complete adjuvant (FCA) and physiological saline, (b) 1% (W/W) of the test substance in physiological saline, and (c) 1:1 (V/V) emulsion of 2% (W/W) test substance in physiological saline and FCA, and 7 days later, further received topically 0.2 ml of the undiluted test substance by a 48-hour closed patch to the initially exposed skin sites (topical induction). Five control animals were given intradermally 0.1 ml each of the samples (a), physiological saline alone and again (a), and 7 days later received the closed patch of distilled water. On day 21 after the initial induction, 0.1 ml each of the 30%, 10%, 3% (W/W each) of the test substance in distilled water and distilled water alone were patched occlusively to the shaved skin of the flank for 24 hours.

In all animals of both test and the control groups, no significant reaction was observed at challenge sites of the skin at 24 and 48 hours after patch-removal

Therefore, it was concluded that the test substance did not demonstrate delayed contact hypersensitivity in the skin of guinea pigs under this test condition.

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

Key study: Experimental results: OECD guideline 406. GLP study.

It was concluded that the test substance did not demonstrate delayed contact hypersensitivity in the skin of guinea pigs under this test condition.


Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

Skin sensitisation: Key study: Experimental results: OECD guideline 406. GLP study.

It was concluded that the test substance did not demonstrate delayed contact hypersensitivity in the skin of guinea pigs under this test condition.

Justification for classification or non-classification

Based on the available information, the substance is not classified as skin sensitiser.