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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:
2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010

Materials and methods

Test guideline
Qualifier:
according to
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.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
Animals: Albino Dunkin Hartley Guinea Pig, CRL:(HA), SPF
Breeder: Charles River Deutschland GmbH
Stolzenseeweg 32-36
88353 Kisslegg / Germany
Number of Animals for Main Study /Pretest:15 males / 3 males
Age at Pretest Start / Beginning of Acclimatization Period: 5-6 weeks
Body Weight at Pretest Start: Pretest groups: 680 -715 g
Body Weight at Beginning of Acclimatization Period: Test and control group: 604 - 748 g
Identification: By unique cage number and corresponding individual ear tag.
Randomization: Selected by hand at time of delivery. No computer generated randomization program.
Acclimatization: Twelve days for the control and test group under laboratory conditions after health examination. No acclimatization for the animals of the pretest. Only animals without any visible signs of illness were used for the study. A certificate of health was provided by the animal supplier at the animal delivery and included in the raw data.
Conditions: Standard Laboratory Conditions: Air-conditioned with ranges for room temperature 22 ± 3 °C, relative humidity 30-70% and approximately 10-15 air changes per hour. Room temperature and humidity were monitored continuously and values outside of these ranges occasionally occurred, usually following room cleaning. These transient variations are considered not to have any influence on the study and, therefore, these data are not reported but are retained at Harlan Laboratories. The animals were provided with an automatically controlled light cycle of 12 hours light and 12 hours dark. Music was played during the daytime light period.
Accommodation: Individually in Makrolon type-4 cages with standard softwood bedding (‘Lignocel’ J. Rettenmaier&Söhne GmbH&CoKG, 73494 Rosenberg / Germany, imported by Provimi Kliba AG, 4303 Kaiseraugst /Switzerland).
Diet: Pelleted standard Provimi Kliba 3418 guinea pig breeding / maintenance diet batch nos. 44/09 and 52/09, containing Vitamin C (Provimi Kliba AG, 4303 Kaiseraugst / Switzerland), ad libitum. Results of analyses for contaminants are archived at Harlan Laboratories Ltd.
Water: Community tap water from Füllinsdorf, ad libitum. Results of bacteriological, chemical and contaminant analyses are archived at Harlan Laboratories Ltd.

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal
Vehicle:
other: Diethylene glycol dimethyl ether
Concentration / amount:
Intradermal induction : 50% dilution of the test item
Epidermal induction 100% (undiluted)
Challenged by epidermal application of the test item at 25%
Second challenge by epidermal application of the test item at 25%
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: Diethylene glycol dimethyl ether
Concentration / amount:
Intradermal induction : 50% dilution of the test item
Epidermal induction 100% (undiluted)
Challenged by epidermal application of the test item at 25%
Second challenge by epidermal application of the test item at 25%
No. of animals per dose:
15 (10 test and 5 control) male albino Dunkin Hartley guinea pigs
Details on study design:
The dose levels of 3-(triethoxysilyl)propiononitrile used in the main study were based on results from intradermal and epidermal pretests.
The intradermal induction of sensitization in the test group was performed in the nuchal region with a 50% dilution of the test item in diglyme and in an emulsion of Freund's Complete Adjuvant (FCA)/physiological saline. The epidermal induction of sensitization was conducted for 48 hours under occlusion with the test item at 100% (undiluted) one week after the intradermal induction. The animals of the control group were intradermally induced with diglyme and FCA/physiological saline and epidermally induced with diglyme under occlusion. Two weeks after epidermal induction the control and test animals were challenged by epidermal application of the test item at 25% in diglyme and diglyme alone under occlusive dressing. Sixteen days after the first challenge a second challenge was performed in the same way as the previous challenge using the test group only and the test item at 25% in diglyme applied on a naive skin site.
Challenge controls:
The animals of the control group were intradermally induced with diglyme and FCA/physiological saline and epidermally induced with diglyme under occlusion.
Positive control substance(s):
yes
Remarks:
ALPHA-HEXYLCINNAMALDEHYDE at 1% (w/w) in PEG 300

Results and discussion

Positive control results:
The sensitivity and reliability of the experimental technique employed was assessed by use of ALPHA-HEXYLCINNAMALDEHYDE which is recommended by the OECD 406 Guidelines and is known to have moderate skin sensitization properties in the guinea pig strain. The results from the most recent test run (Harlan Laboratories Study C50652, performed from 27-May-2009 to 20-Jul-2009) ) follow:
One out of 10 test animals showed skin reactions after the first challenge treatment with ALPHA-HEXYLCINNAMALDEHYDE at 1% (w/w) in PEG 300. No skin effect was observed in the control group. Eighty to ninety percent of the test animals showed discrete/patchy erythema at the 24- or 48-hour reading
after the second challenge treatment with ALPHA-HEXYLCINNAMALDEHYDE at 3% (w/v) in PEG 300. No skin effect was observed in the control group.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25%
No. with + reactions:
1
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
25%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
25%
No. with + reactions:
5
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
0%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
25%
No. with + reactions:
4
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
0%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
rechallenge
Hours after challenge:
24
Group:
test group
Dose level:
25%
No. with + reactions:
1
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
rechallenge
Hours after challenge:
24
Group:
test group
Dose level:
0%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
rechallenge
Hours after challenge:
48
Group:
test group
Dose level:
25%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
rechallenge
Hours after challenge:
48
Group:
test group
Dose level:
0%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
1% alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
8
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
1% alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
9
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In an in vivo skin sensitisation study in guinea pigs, conducted according to OECD TG 406 and in compliance with GLP, the test substance, 3-(triethoxysilyl)propanenitrile, was concluded to be not sensitising to skin.