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Description of key information

Guinea-pig data indicate that the test substance does not have skin sensitising potential.

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:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
not specified
Type of study:
Buehler test
Justification for non-LLNA method:
Currently no LLNA study is available for assessment. The Buehler test has been carried out as an animal test to predict human sensitization for over a decade and is recommended by international test guidelines such as OECD.

Specific details on test material used for the study:
- Name of the test item (as cited in study report): Tellurium diethyldithiocarbamate
- Batch No.: C 0131100 NF
- Appearance: Yellow, powder
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: D. Hall, Newchurch, Staffordshire, England, obtained on 24 october 1985.
- Weight at study initiationt: 300-350g
- Age at study initiation: 4-5 weeks
- Housing: The guinea-pigs were housed individually in suspended cages with wire mesh floors
- Diet: Vitamin C-enriched Guinea-Pig Diet F.D.l (Special Diets Services Limited) (ad libitum). Hay was given once weekly.
- Water: tap water (ad libitum)
- Acclimation period: 13 days

ENVIRONMENT
- Temperature: 21 °C
- Humidity: 30-70%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 / 12
Route:
epicutaneous, occlusive
Vehicle:
paraffin oil
Concentration / amount:
0.5 ml of the test substance, 50% w/w in liquid paraffin.
Day(s)/duration:
9 days in 3 weeks / 6 hours exposure
Adequacy of induction:
not specified
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
paraffin oil
Concentration / amount:
0.5 ml of the test substance, 50% w/w in liquid paraffin.
Day(s)/duration:
6 hours
Adequacy of challenge:
not specified
No. of animals per dose:
10
Details on study design:
INDUCTION
Prior to each induction application, the skin on the left shoulder region of the guinea-pig was clipped free of hair using electric clippers. A 2 x 2 cm patch of surgical gauze (three layers thick) was saturated with approximately 0.5 ml of the test substance, 50% w/w in liquid paraffin. The patch was placed on the skin and covered by a length of impermeable plastic adhesive tape (5 cm width "Blenderm"). This in turn was firmly secured by elastic adhesive bandage ("Elastoplast" 5 cm width) wound round the torso of the animal and fixed with "Sleek" impervious plastic adhesive tape. Contact with the skin was maintained for approximately 6 hours for each induction exposure. The dressings were then removed and the resulting dermal reactions assessed approximately 24 hours later for erythema and oedema. Nine induction applications were made in this manner three times a week during a three week period.

CHALLENGE
The test and untreated control animals were challenged topically two weeks after the ninth induction application using the test substance, 50% w/w in liquid paraffin. Hair was removed by clipping from a 5 x 5 cm area on the right flank of each guinea-pig. A 2 x 2 cm gauze patch (3 layers thick) was saturated with approximately 0.5 ml of the test sample in a similar fashion to that used for the induction applications. The patch was sealed to the flank for approximately 6 hours under a 5 cm strip of "Blenderm" covered by "Elastoplast" wound round the trunk and secured with "Sleek". The untreated controls were treated similarly to the test animals, but received the test sample applied specifically to an anterior site on the left flank.

The challenge site was evaluated 24, 48 and 72 hours after removal of the patch.
Positive control substance(s):
no
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test chemical
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
No. with + reactions:
0
Total no. in group:
10
Key result
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
negative control
No. with + reactions:
0
Total no. in group:
10

RESULTS

Clinical signs

There were no signs of ill health or toxicity observed in any of the test or untreated control animals throughout the duration of the study.

Bodyweight changes

Bodyweight changes recorded in the test animals were similar to those noted in the untreated control animals.

Induction

The numerical scores awarded to the dermal reactions observed in test and untreated control animals are 0; no erythema and oedema observed.

Although induction sites of test animals were stained yellow, assessment of the erythema was not hindered.

Challenge

The numerical scores awarded to the dermal reactions elicited by the challenge application with the substance, 50% w/w in liquid paraffin are 0; no erythema and oedema observed.

There was no dermal irritation in any of the test or untreated control animals.

Interpretation of results:
GHS criteria not met
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Skin sensitisation potential
In a pre-GLP study similar to OECD TG 406, skin sensitisation potential was assessed using ten albino guinea-pigs.

Induction: Prior to each induction application, the skin on the left shoulder region of the guinea-pig was clipped free of hair using electric clippers. A 2 x 2 cm patch of surgical gauze (three layers thick) was saturated with approximately 0.5 ml of the test substance, 50% (w/w) in liquid paraffin and occlusively placed on the skin. Contact with the skin was maintained for approximately 6 hours for each induction exposure. The dressings were then removed and the resulting dermal reactions assessed approximately 24 hours later for erythema and oedema. Nine induction applications were made in this manner three times a week during a three week period.

Challenge: The test and untreated control animals were challenged topically two weeks after the ninth induction application using the test substance, 50% (w/w) in liquid paraffin. Hair was removed by clipping from a 5 x 5 cm area on the right flank of each guinea-pig. A 2 x 2 cm gauze patch (3 layers thick) was saturated with approximately 0.5 ml of the test sample in a similar fashion to that used for the induction applications. The untreated controls were treated similarly to the test animals, but received the test sample applied specifically to an anterior site on the left flank. The challenge site was evaluated 24, 48 and 72 hours after removal of the patch.

No clinical signs or effects on body weight gain were observed throughout the study. No dermal irritation was observed.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

No sensitisation was observed therefore classification of this substance for skin and respiratory sensitisation is not warranted according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.