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Administrative data

Description of key information

In the key study performed according to OECD Test Guideline 406 (guinea pig maximisation test) and in compliance with GLP, dicyclopentyl(dimethoxy)silane (CAS 126990-35-0) was not sensitising to the skin (Safepharm Laboratories Ltd., 1996a).

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:
03.07.1995 to 10.08.1995
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
other: 92/69/EEC
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
An LLNA study was not performed because there is an existing reliable study for skin sensitisation using the Guinea Pig Maximisation test method. Furthermore, the LLNA test method is not considered to be suitable for substances that contain silicon. Please refer to the attached document for further details.
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: David Hall Ltd., UK
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 324-396 g
- Housing: Individual or paired in polypropylene cages
- Diet (e.g. ad libitum):
- Water (e.g. ad libitum):
- Acclimation period: At least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-21
- Humidity (%): 46-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 03.07.1995 to 10.08.1995
Route:
intradermal and epicutaneous
Vehicle:
arachis oil
Concentration / amount:
Concentration of test material and vehicle used at induction: 25% w/v in arachis oil BP for intradermal induction. 100% for topical induction Concentration of test material and vehicle used for each challenge: 100% and 25% v/v in arachis oil BP.
Route:
epicutaneous, occlusive
Vehicle:
arachis oil
Concentration / amount:
Concentration of test material and vehicle used at induction: 25% w/v in arachis oil BP for intradermal induction. 100% for topical induction Concentration of test material and vehicle used for each challenge: 100% and 25% v/v in arachis oil BP.
No. of animals per dose:
Test group: 20
Negative control group: 10
Details on study design:
RANGE FINDING TESTS: Intradermal induction: 0.1 ml of 1, 5, 10 and 25% w/v in arachis oil B.P. were tested in four guinea pigs by injection. Erythema was scored up to seven days after the injection. The highest concentration to cause only mild to moderate skin irritation, and which was well tolerated systemically was selected for the intradermal induction stage of the main study.
Topical induction: Two guinea pigs (intradermally injected with FCA 14 days earlier) were treated with undiluted test substance and 75, 50 ad 25% v/v in arachis oil B.P. Applications were occluded for 48 hours. The degree of erythema and oedema was evaluated at 1, 24 and 48 hours after dressing removal. The highest concentration that produced mild to moderate dermal irritation was selected for the topical induction stage of the main study.

Topical challenge: The undiluted test substance and 75, 50 and 25% v/v in arachis oil B.P. were applied under an occlusive dressing to two guinea pigs for 24 hours. Erythema was evaluated at 1, 24 and 48 hours after dressing removal. The highest non-irritant concentration and one lower concentration were selected for the topical challenge stage of the main study.

MAIN STUDY
A. INDUCTION EXPOSURE
Shortly before treatment on Day 0 the hair was removed from an area on the shoulder region of each animal. A row of three injections (0.1 ml) was made on each side of the mid-line. The injections were:

a) FCA plus distilled water in the ratio 1: 1
b) a 25% w/v solution of the test substance in arachis oil B.P.
c) a 25% w/v emulsion of the test substance in a 1:1 preparation of FCA plus distilled water.

Approximately 24 and 48 hours after the injection erythema at the test site was evaluated.

One week later (Day 7) the same area on the shoulder region used for the injections was clipped and treated with a topical application of the undiluted test substance. The patch was held in place with an occlusive dressing for 48 hours. The degree of erythema and oedema was scored 1 and 24 hours following removal of the patches.

Negative controls: Intradermal injections were:
a) FCA plus distilled water in the ratio 1: 1
b) arachis oil B.P.
c) a 50% w/v formulation of arachis oil B.P. in FCA/distilled water 1:1.

Topical applications followed the same procedure as for the test animals except that nothing was applied to the patch held under the occlusive dressing.

B. CHALLENGE EXPOSURE
Shortly before treatment on Day 21, an area on both flanks of each animal, was clipped. A patch of filter paper saturated with undiluted test substance was applied to the right flank and held in place with an occlusive dressing. A 75% v/v in arachis oil B.P. was similarly applied to the left flank (to ensure maximum non-irritant concentration used). After 24 hours the dressing was removed and the site swabed with cotton wool soaked in a suitable solvent. The degree of erythema and oedema was graded at 24 and 48 hours after patch removal.
Positive control substance(s):
no
Remarks:
but historical positive controls for the laboratory reported.
Positive control results:
Historical positive controls gave appropriate results.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
20
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
75 %
No. with + reactions:
0
Total no. in group:
20
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
20
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
75 %
No. with + reactions:
0
Total no. in group:
20
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
10
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
75 %
No. with + reactions:
0
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100 %
No. with + reactions:
0
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
75 %
No. with + reactions:
0
Total no. in group:
10
Reading:
1st reading
Group:
positive control
Remarks on result:
other: positive control was not included but historical controls were done periodically
Interpretation of results:
GHS criteria not met
Conclusions:
In a guinea pig maximisation study conducted according to OECD Test Guideline 406 and in compliance with GLP, dicyclopentyl(dimethoxy)silane was not sensitising to the skin.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Several guinea pig maximisation studies are available for this substance. These studies were all negative.


Respiratory sensitisation

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

Justification for classification or non-classification

Based on the available data, dicyclopentyl(dimethoxy)silane does not meet the criteria for classification as a skin sensitiser according to Regulation (EC) No 1272/2008. There are no data to suggest that classification as a respiratory sensitiser is required.