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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:
19 June 1998 - 13 July 1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, performed in accordance with valid guidelines and the study was conducted under GLP conditions.
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: approximately 3 months
- Weight at study initiation (mean ± standard deviation): 362 ± 17 g (males); 362 ± 18 g (females)
- Housing: individually in polycarbonate cages (48 x 27 x 20 cm)
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2 °C
- Humidity (%): 30 - 70 %
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light

IN-LIFE DATES: From: 19 June 1998 To: 13 July 1998
Route:
intradermal and epicutaneous
Vehicle:
other: isotonic saline solution (0.9 % NaCl)
Concentration / amount:
INDUCTION
Test group:
- intradermal: Anterior: Freud's Complete Adjuvant (FCA) diluted at 50 % with (v/v) with sterile isotonic saline solution (0.9 % NaCl)
Middle: 20 % (w/w) test substance in sterile isotonic saline solution (0.9 % NaCl)
Posterior: 20 % (w/w) test substance in a mixture of FCA and sterile isotonic saline solution (0.9 % NaCl) 50/50 (v/v)
- topical: applied unchanged (no vehicle)

Control group:
- intradermal: Anterior: Freud's Complete Adjuvant (FCA) diluted at 50 % with (v/v) with sterile isotonic saline solution (0.9 % NaCl)
Middle: vehicle
Posterior: 50 % (w/w) vehicle in a mixture of FCA and sterile isotonic saline solution (0.9 % NaCl) 50/50 (v/v)
- topical: applied unchanged (no vehicle)

CHALLENGE:
- topical: 10 % (w/w) test substance in sterile isotonic saline solution (0.9 % NaCl) for both test and control groups.
Route:
epicutaneous, occlusive
Vehicle:
other: isotonic saline solution (0.9 % NaCl)
Concentration / amount:
INDUCTION
Test group:
- intradermal: Anterior: Freud's Complete Adjuvant (FCA) diluted at 50 % with (v/v) with sterile isotonic saline solution (0.9 % NaCl)
Middle: 20 % (w/w) test substance in sterile isotonic saline solution (0.9 % NaCl)
Posterior: 20 % (w/w) test substance in a mixture of FCA and sterile isotonic saline solution (0.9 % NaCl) 50/50 (v/v)
- topical: applied unchanged (no vehicle)

Control group:
- intradermal: Anterior: Freud's Complete Adjuvant (FCA) diluted at 50 % with (v/v) with sterile isotonic saline solution (0.9 % NaCl)
Middle: vehicle
Posterior: 50 % (w/w) vehicle in a mixture of FCA and sterile isotonic saline solution (0.9 % NaCl) 50/50 (v/v)
- topical: applied unchanged (no vehicle)

CHALLENGE:
- topical: 10 % (w/w) test substance in sterile isotonic saline solution (0.9 % NaCl) for both test and control groups.
No. of animals per dose:
2 males and 2 females (preliminary test)
5 males and 5 females (control group)
10 males and 10 females (treatment group)
Details on study design:
RANGE FINDING TESTS
A preliminary study was conducted to inform on test concentrations to be used in the main study. The maximal practicable concentration by both the intradermal, and cutaneous route, was 20 % and this was selected for the main study.

MAIN STUDY
On day 1, the dorsal region between the shoulders, was clipped free of fur and intradermal injections of Freund's complete adjuvant mixed with 0.1 mL test material (treatment group) or the vehicle (control group) were prepared and injected. On day 7, the same region received a topical application of 0.5 mL sodium laurylsulphate in vaseline (10 % w/w) in order to induce local irritation.

On day 8, the same test site was treated by topical application of 500 mg of unchanged test material (treatment group) or 0.5 mL vehicle (control group) and was covered by an occlusive dressing, covering 4 cm x 2 cm, for 48 hours. Cutaneous reactions were recorded 1 hour after removal of the occlusive dressing.

After a rest period of 12 days, all animals of the treatment and control groups were challenged by a topical application of the 10 % w/w test material on the right flank. The left flank served as the control and received 0.5 mL vehicle only. Test material and vehicle were maintained under an occlusive dressing for 24 hours. Skin reactions were evaluated approximately 24 and 48 hours later according to the scale outlined in the field "Any other information on materials and methods incl. tables".

The animals were observed twice a day during the study in order to check for clinical signs and mortality. The animals were weighed individually on the day of allocation into the groups, on the first day of the study and again on test days 8, 15 and 25.

At the end of the study, animals were killed. No necropsy was performed and no skin samples were taken from the challenge application sites. No histological examination was performed.
Positive control substance(s):
yes
Remarks:
2,4-dinitro-1-chlorobenzene and mercaptobenzothiazole
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10 %
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 10 %. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
10 %
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 10 %. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
10 %
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 10 %. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
10 %
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 10 %. No with. + reactions: 0.0. Total no. in groups: 10.0.
Clinical examionations - No clinical signs were observed during the study.

-The body weight gain of the treated animals was normal when compared to the controls.

Scoring cutaneous reactions

- On day 10, after the cutaneous application of the induction period, signs of irritation were observed at the interscapular test site in the control group. For the treated group, scoring was masked by the colouration of the skin.

- No cutaneous reactions were observed after the challenge application although an orange colouration of the skin, which could have masked a very slight erythema (grade 1), was noted at the 24 hour reading in almost all the animals.

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Under the conditions of the study, no cutaneous reactions, which could be attributable to the sensitisation potential of the test material, were observed. The study is considered to be reliable, relevant and adequate for risk assessment and classification and labelling purposes.
Executive summary:

The skin sensitisation potential of the test material was determined in accordance with standardised guidelines OECD 406 and EU Method B.6 using the Guinea-pig Maximisation Test. The test material was dosed as a 20 % w/w preparation in isotonic saline solution in an intradermal and unchanged in a topical induction phase. The test material was dosed as a 10 % w/w preparation in isotonic saline solution during a challenge application. The positive controls were shown to have the capacity to cause skin sensitisation confirming the validity of the protocol used for this study. Under the conditions of the study, no cutaneous reactions, which could be attributable to the sensitisation potential of the test material, were observed.

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

The skin sensitisation potential of the test material was determined in accordance with standardised guidelines OECD 406 and EU Method B.6 using the Guinea-pig Maximisation Test. The test material was dosed as a 20 % w/w preparation in isotonic saline solution in an intradermal and unchanged in a topical induction phase. The test material was dosed as a 10 % w/w preparation in isotonic saline solution during a challenge application. The positive controls were shown to have the capacity to cause skin sensitisation confirming the validity of the protocol used for this study. Under the conditions of the study, no cutaneous reactions, which could be attributable to the sensitisation potential of the test material, were observed.

The study was performed in line with GLP and accepted standardised guidelines with a high standard of reporting. The study was assigned a reliability score of 1 in accordance with the criteria for assessing data quality as outlined in Klimisch (1997) and considered suitable for assessment as an accurate reflection of the test material.

The available data are considered to be complete and the conclusion, not sensitising, was taken forward for risk assessment.


Migrated from Short description of key information:
Not sensitising, male/female Guinea pig, OECD 406, EU Method B.6, Manciaux 1998c

Justification for selection of skin sensitisation endpoint:
Only one study is available.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

In accordance with with criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the test material did not elicit a response in the Guinea pig Maximisation Test and therefore does not meet the criteria for classification as a skin sensitiser.