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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
Study period:
from August 10, 1992 to September 13, 1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report date:
1992

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
not specified
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
GLP compliance:
yes (incl. QA statement)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
A LLNA study does not need to be conducted because adequate data from a guinea pig maximisation test is already available.

Test material

Constituent 1
Chemical structure
Reference substance name:
2-phenyl-1H-benzimidazole-5-sulphonic acid
EC Number:
248-502-0
EC Name:
2-phenyl-1H-benzimidazole-5-sulphonic acid
Cas Number:
27503-81-7
Molecular formula:
C13H10N2O3S
IUPAC Name:
2-phenyl-1H-benzimidazole-5-sulphonic acid

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
test animals
Thirty-six female, albino Dunkin-Hartley guinea pigs were supplied by David Hal 1 Limited, Burton-on-Trent, Staffordshire, U.K. At the start of the main study the animals weighed 319 - 427g, and were approximately eight to twelve weeks old. After a minimum acclimatisation period of five days, each animal was selected at random and given a period of five days, each animal was selected at random and given a number unique within the study which was written on a small area of clipped rump using a black indelible marker-pen.
Husbandry
The animals were housed in groups of up to three in solid floor polypropylene cages furnished with softwood shavings. Free access to mains tap water and food (Guinea Pig FD1 Diet, Special Diet Services Limited, Witham, Essex, U.K.) was allowed throughout the study.
The animal room was maintained at a temperature of 20 - 23°C and relative humidity of 51-68%. The rate of air exchange was approximately 15 changes per hour and the lighting was controlled by a time switch to give 12 hours light and 12 hours darkness.

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal and epicutaneous
Vehicle:
arachis oil
Concentration / amount:
Intradermal Induction : 1% w/v in arachis oil B.P.
topic induction: 50% w/w in arachis oil B.P.
Topical challenge: 25% and 10% w/w in arachis oil B.P.
Challenge
Route:
epicutaneous, occlusive
Vehicle:
arachis oil
Concentration / amount:
Intradermal Induction : 1% w/v in arachis oil B.P.
topic induction: 50% w/w in arachis oil B.P.
Topical challenge: 25% and 10% w/w in arachis oil B.P.
No. of animals per dose:
10/dose, twenty test and ten control.
Details on study design:
a)Induction (contd)
Induction of the Test Animals (contd)
i) Freund's Complete Adjuvant plus distilled water in the ratio 1:1.
ii) a 1% (w/v) dilution of test material in arachis oil B.P.
iii) a 1% (w/v) dilution of test material in a 1:1 preparation of Freund's Complete Adjuvant plus arachis oil B.P.
One week later (Day 7), the same area on the shoulder region used previously for intradermal injections was clipped again and treated with a topical application of the test material formulation (50% w/w in arachis oil B.P.). The test material formulation (0.2 - 0.3 ml) was applied on filter paper (WHATMAN No.4: approximate size 40 mm x 20 mm) which was held in place by a strip of surgical adhesive tape (BLENDERM: approximate size 60 mm x 25 mm) and covered with an overlapping length of aluminium foil. The patch and foil were further secured by a strip of elastic adhesive bandage (ELASTOPLAST:approximate size 250 mm x 35 mm) wound in a double layer around the torso of each animal. This occlusive dressing was kept in place for 48 hours.
Induction of the Control Animals:
Intradermal injections were adiministered using an identical procedure to that used for the test animals, except that the injections were:
i) Freund's Complete Adjuvant plus distilled water in the ratio 1:1.
ii) arachis oil B.P.
iii) FreuncTs Complete Adjuvant plus arachis oil B.P. in the ratio 1:1
b) Challenge
Shortly before treatment on Day 21, an area, approximately 50 mm x 70 mm on both flanks of each animal, was clipped free of hair with veterinary clippers.
A quantity of 0.1 - 0.2 ml of the test material formulation (25% w/w in arachis oil B.P.) was applied to the shorn right flank of each animal on a square of filter paper (WHATMAN No.4: approximate size 20 mm x 20 mm) which was held in place by a strip of surgical adhesive tape (BLENDERM: approximate size 40mm x 50 mm). To ensure that the maximum non-irritant concentration was used at challenge, the test material at a concentration of 10% (w/w) in arachis oil B.P. was also similarly applied to a separate skin sites on the right shorn flank. The vehicle alone was similarly applied to the left shorn flank. The patches were occluded with an overlapping length of aluminium foil and secured by a strip of elastic adhesive bandage (ELASTOPLAST: approximate size 250 mm x 75 mm) wound in a double layer around the torso of each animal.
After 24 hours, the dressing was carefully cut using blunt-tipped scissors, removed and discarded. The treatment sites were decontaminated with diethyl ether and the position of the treatment sites identified by using a black indelible marker-pen.

A response in at least 30% of the animals is considered positive.
Challenge controls:
arachis oil
Positive control substance(s):
yes
Remarks:
2,4-Dinitrochlorobenzene (DNCB)

Results and discussion

Positive control results:
The known contact sensitiser, 2,4-Dinitrochlorobenzene (DNCB), produced a 89 % (16/18) sensitisation rate. This was considered to be a satisfactory sensitisation response for this material under the conditions of the test.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
3
Group:
positive control
Dose level:
0.2%
No. with + reactions:
10
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation
Remarks:
Dinitrochlorobenyene was used 2% for induction and 0.2% for chalange
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25% and 10% w/w in arachis oil B.P.
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
One test animal was found dead on day 18.
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25% and 10% w/w in arachis oil B.P.. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: One test animal was found dead on day 18. .
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25% and 10% w/w in arachis oil B.P.
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
One test animal was found dead on day 18.
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25% and 10% w/w in arachis oil B.P.. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: One test animal was found dead on day 18. .
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
arachis oil
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: arachis oil. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no data.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
arachis oil
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: arachis oil. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no data.

Any other information on results incl. tables

a) Skin Reactions Observed After Topical Induction

Scattered mild redness and moderate and diffuse redness were elicited by the test material. Residual test material on the test site was commonly noted following topical induction.

b) Skin Reactions Observed After Topical Challenge

One test animal was found dead on day 18. The cause of death was not determined but the absence of this animal was considered not to affect the purpose or integrity of the study.

No adverse reactions were noted at the test material and vehicle control sites of the test or control animals at the 24 and 48-hour

observations.


Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Based on the result given in this study, test article was considered to be a non-sensitiser to guinea pig skin.
Executive summary:

This study was conducted to assess the skin contact sensitisation potential of the test article in the albino guinea pig, which followed OECD guidelines 406 'skin sensitisation' and GLP principle.Cutaneous reactions, i.e erythema and oedema formation were evaluated at 24 and 48 hours after removal of the dressing. One test animal was found dead on day 18, which was considered to be an incidental finding. The test article produced a 0 % (0/19) sensitisation rate. After the challenge application no skin reactions were observed in the animals of the test article treated and control group. No toxic symptoms were evident in the guinea pigs of either the control and test group.