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Description of key information

The in vivo skin sensitisation of Decyltrimethoxysilane was evaluated during a GLP-compliant study performed according to the method described by Buehler. This method is described in the OECD Testing Guideline 406.

Six male and six female Hartley albino guinea pigs received three topical, occluded applications of the test substance at 50% in corn oil during the induction period of three weeks. An additional group of five male and five female Hartley albino guinea pigs served as a control group.

Two weeks following the last induction application, the animals in the test group received a topical application of the test article, at the determined highest non-irritating concentration of 25% in corn oil, to a dorsal, virgin site. At the same time, the control group animals received an identical dosage of the test article. All challenges dosages were made without patches.

Observations of irritation and other effects were recorded 7 and 24 hours after each induction application and 7, 24 and 48 hours following the challenge applications.

None of the treated animals showed any sign of irritancy at 7, 24 and 48 hours following the challenge.

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 14 October 2004 to 19 November 2004
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)
Deviations:
yes
Remarks:
Reduced number of animals compared to number recommended in the Guideline.
GLP compliance:
yes (incl. QA statement)
Type of study:
Buehler test
Justification for non-LLNA method:
Existing study performed in 2004 is used for the purpose of the REACH Registration of the substance.
Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Ace Animals (Chelmsford, Massachusetts)
- Weight at study initiation: 326 to 446 g
- Housing: stainless steel cages
- Diet: Certified Guinea Pig Diet #5026 ad libitum
- Water: water (source not specified) ad libitum
- Acclimation period: eight days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 65 to 75°F (equivalent to 18.33 to 23.89°C)
- Humidity (%): Monitored (variations not specified)
- Photoperiod (hrs dark / hrs light): 12h/12h
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
0.4 mL test substance at 50% in corn oil
Day(s)/duration:
Applications of six hours were made once per week for three consecutive weeks.
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
0.4 mL test substance at 25% in corn oil
Day(s)/duration:
6h
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
Six animals per sex
Details on study design:
RANGE FINDING TESTS: Mildly irritating and highest non-irritating concentrations were determined before the induction phase.

MAIN STUDY
A. INDUCTION EXPOSURE
- Exposure period: 6h
- Test groups: One treated group
- Control group: Five animals per sex
- Site: n°1
- Frequency of applications: 3
- Duration: 3 weeks
- Concentrations: 50% in corn oil

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge:
- Exposure period: 6h
- Test groups: One treated group
- Control group: Five animals per sex
- Site: n°3
- Concentrations: 25% in corn oil
- Evaluation: 7, 24, and 48 hr after challenge
Positive control substance(s):
no
Reading:
1st reading
Hours after challenge:
7
Group:
test chemical
Dose level:
25% in corn oil
No. with + reactions:
0
Total no. in group:
12
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25% in corn oil
No. with + reactions:
0
Total no. in group:
12
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25% in corn oil
No. with + reactions:
0
Total no. in group:
12
Reading:
1st reading
Hours after challenge:
4
Group:
negative control
Dose level:
25% in corn oil
No. with + reactions:
0
Total no. in group:
10
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25% in corn oil
No. with + reactions:
0
Total no. in group:
10
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
25% in corn oil
No. with + reactions:
0
Total no. in group:
10
Interpretation of results:
GHS criteria not met
Conclusions:
The skin sensitisation of Decyltrimethoxysilane was evaluated using the Buelher’s Test. None of the treated animals showed any sign of irritancy at 7, 24 and 48 hours following the challenge. The substance does not meet the criteria for classification as a skin sensitiser in accordance with Regulation (EC) No.1272/2008.
Executive summary:

The in vivo skin sensitisation of Decyltrimethoxysilane was evaluated during a GLP-compliant study performed according to the method described by Buehler. This method is described in the OECD Testing Guideline 406.

Six male and six female Hartley albino guinea pigs received three topical, occluded applications of the test substance at 50% in corn oil during the induction period of three weeks. An additional group of five male and five female Hartley albino guinea pigs served as a control group.

Two weeks following the last induction application, the animals in the test group received a topical application of the test article, at the determined highest non-irritating concentration of 25% in corn oil, to a dorsal, virgin site. At the same time, the control group animals received an identical dosage of the test article. All challenges dosages were made without patches.

Observations of irritation and other effects were recorded 7 and 24 hours after each induction application and 7, 24 and 48 hours following the challenge applications.

None of the treated animals showed any sign of irritancy at 7, 24 and 48 hours following the challenge.

The substance does not meet the criteria for classification as a skin sensitiser in accordance with Regulation (EC) No.1272/2008.

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

Justification for classification or non-classification

The skin sensitisation of Decyltrimethoxysilane was evaluated using the Buelher’s Test. None of the treated animals showed any sign of irritancy at 7, 24 and 48 hours following the challenge. The substance does not meet the criteria for classification as a skin sensitiser in accordance with Regulation (EC) No.1272/2008.