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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:
supporting study
Study period:
10.02.1995 to 23.09.1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report date:
1996

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
EPA OPP 81-6 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
other: the Toxic Substance Control Act (TSCA) Health Effects Test Guidelines 40 CFR 798.4350
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
other: the Japanese Agricultural Chemicals Laws and Regulations Testing Guidelines for Toxicology Studies published by the Society of Agricultural Chemical Industry, under the auspices of the Ministry of Agriculture, Forestry and Fisheries (MAFF)
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The non-LLNA study was already available and a new test was not conducted.

Test material

Constituent 1
Reference substance name:
vinylsilanetriol
IUPAC Name:
vinylsilanetriol
Test material form:
liquid

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Sprague Dawley, Inc.
- Age at study initiation: 'Young adult'
- Weight at study initiation: 320 to 393 g
- Housing: Individual in suspended wire-mesh cages
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: Seven days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 22
- Humidity (%): 36 - 66
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 02.03.1995 To: 02.04.1995

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
other: acetone
Concentration / amount:
5% TM in acetone, 5% TM in a 1:1 mixture of Freund's Complete Adjuvant (FCA):sterile saline and a 1:1 mixture of FCA:sterile saline
Route:
epicutaneous, occlusive
Vehicle:
other: acetone
Concentration / amount:
50% TM in acetone
Day(s)/duration:
48 hours
Challenge
Route:
epicutaneous, occlusive
Vehicle:
other: acetone
Concentration / amount:
10% w/v mixture in acetone
Day(s)/duration:
24 hours
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
Definitive study:
10/sex/dose with test material
5/sex/dose with Positive Control
5/sex/dose with Negative Control
Details on study design:
The guinea pigs in the definitive sensitization maximization test undergo an intradermal induction stage, followed by a topical induction stage, and a subsequent challenge and rechallenge period.
Primary lrritation Phase: The test material was prepared for dosing as weight-to-volume suspensions at concentrations of 0.5%, 1.0%, 2.5%, 5%, 10%, 25 and 50%. The appropriate amount of test material for each concentration was weighed out and acetone added in sufficient quantity to obtain the desired concentrations. Sufficient undiluted test material and acetone were also dispensed for dosing.

Intradermal Induction Phase:
The test material, a 5% w/v mixture in acetone, was prepared for injection by diluting 0.5 g of the test material to a total volume of 10 ml with acetone.
The test material, a 5% w/v mixture in 1:1 Freund's Complete Adjuvant (FCA) and sterile saline solution, was prepared for injection by mixing 0.5 g of the test material in 5 ml of FCA and 5 ml of sterile saline.
A sufficient amount of the 1:1 mixture of FCA and sterile saline was dispensed for dosing the Test Group, Negative ControI-I and II Group and Positive Control Group.
The positive control material, 0.25% w/v mixture in 80% ethanol, was prepared for injection by diluting 0.025 g of ground dinitrochlorobenzene (DNCB) to a total volume of 10 ml with 80% ethanol.
The positive control material, 0.25% w/v mixture in 1:1 FCA and sterile saline, was prepared for injection by mixing 0.025 g of ground DNCB with 5 ml of FCA
and 5 ml of sterile saline.
The vehicle material, 5% w/v mixture in 1:1 FCA and sterile saline, was prepared for injection by mixing 0.5 g of acetone with 5 ml of FCA and 5 ml of
sterile saline.
Sufficient acetone was dispensed for dosing the vehicle control sites an the negative control animals.

Topical Induction Phase:
The test material was prepared for dosing the Test Group as a 50% w/v solution in acetone by diluting 5.0 g of test material to a total volume of 10 ml.
The positive control material, DNCB, was prepared for dosing the Positive Control Group as a 0.25% w/v solution in 80% ethanol by diluting 0.025 g of preground DNCB to a total volume of 10 ml.
Sufficient acetone was dispensed for dosing the negative control animals.

During the intradermal induction stage, the test article, vehicle, and positive control, respectively, with or without Freund's complete adjuvant (FCA), were injected intradermally. Intradermal induction consisted of injections of 5% TM in acetone, 5% TM in a 1:1 mixture of Freund's Complete Adjuvant (FCA):sterile saline and a 1:1 mixture of FCA:sterile saline. Seven days after the intradermal injections, a patch, saturated with 50% TM in acetone, vehicle control or positive control was applied to the injection area, and covered with an occlusive dressing for 48 hours.

Challenge Phase:
The test material was prepared for challenge dosing as a 10% w/v mixture in acetone by diluting 1.0 g of test material to a total volume of 10 ml.
Sufficient acetone was dispensed for dosing valide control sites.
The positive control material, DNCB, was prepared for challenge dosing as a 0.1 w/v solution in 80% ethanol by diluting 0.01 g of ground DNCB to a total volume of 10 ml.
Sufficient 80% ethanol was dispensed for dosing vehicle control sites.

14 days after topical induction, the animals were challenged with 10% TM in acetone, vehicle control or positive control. All challenge doses were applied under Hill Top Chambers® with adhesive backs removed, to previously unexposed areas of skin. The chambers were occluded with plastic wrap and over wrapped with tape for 24 hours. Twenty-four hours after dosing, the occlusive cover was removed. Application sites were evaluated at approximately 24 and 48 hours after patch removal.

Rechallenge Phase:
The test material was prepared for rechallenge dosing as a 10% w/v mixture in acetone by diluting 1.0 g of test material to a total volume of 10 ml.
Sufficient acetone was dispensed for dosing vehicle control sites.

One week following challenge dosing, 10% TM in acetone was administered to previously unexposed sites on the animals using the procedures described above. Twenty-four hours following unwrapping, the rechallenge exposure sites were scored for irritation. The sites were re-examined 24 hours following the first scoring.

Body weights were recorded prior to initiation of dosing and at termination.
Challenge controls:
A positive control group of five male and five female guinea pigs was included to verify the reliability of the test system. The positive control group was induced and challenged on a similar regimen as the test group using dinitrochlorobenzene (DNCB) in 80% ethanol as the positive control material. Separate sites were dosed with 80% ethanol to detect any reactions related to the vehicle.

Negative control groups I and II of five male and five female guinea pigs each were dosed with the vehicle during induction and in the same manner as the test group at challenge and served as irritation controls.
Positive control substance(s):
yes
Remarks:
dinitrochlorobenzene (DNCB)

Results and discussion

Positive control results:
Based on the sensitization incidence index of 100%, the positive control material, DNCB, was found to be an extremely sensitizing agent in the albino guinea pig under the conditions of this study, thereby verifying the reliability of the test system.  The positive control vehicle, 80% ethanol, was demonstrated to be nonsensitizing under the conditions of this study.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10% TM in acetone
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
Irritation severity index 1.1
Remarks on result:
no indication of skin sensitisation
Remarks:
sensitization incidence index 5%
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
10% TM in acetone
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
Irritation severity index 0.3
Remarks on result:
no indication of skin sensitisation
Remarks:
sensitization incidence index 5%
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100 % acetone
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
Irritation severity index 0.6
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100% acetone
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
Irritation severity index 0.1
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
10% TM in acetone
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0.6
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
10% TM in acetone
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0.6
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100% acetone
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0.2
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100% acetone
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.1% DNCB in 80% ethanol
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
Irritation severity index 1.6
Remarks on result:
positive indication of skin sensitisation
Remarks:
Based on the sensitization incidence index of 100%, the positive control material, DNCB, was found to be an extremely sensitizing agent in the albino guinea pig under the conditions of this study, thereby verifying the reliability of the test system.  The positive control vehicle, 80% ethanol, was demonstrated to be nonsensitizing under the conditions of this study.
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
0.1% DNCB in 80% ethanol
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
Irritation severity index 2
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
80% ethanol
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
80% ethanol
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0
Remarks on result:
no indication of skin sensitisation
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
10% TM in acetone
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
Irritation severity index 1
Remarks on result:
no indication of skin sensitisation
Remarks:
sensitization incidence index 0%
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
10% TM in acetone
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
Irritation severity index 0.4
Remarks on result:
no indication of skin sensitisation
Remarks:
sensitization incidence index 0%
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
10% TM in acetone
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 1
Remarks on result:
no indication of skin sensitisation
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
10% of TM in acetone
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0.7
Remarks on result:
no indication of skin sensitisation
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
100% acetone
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0.8
Remarks on result:
no indication of skin sensitisation
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
100% in acetone
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Irritation severity index 0.2
Remarks on result:
no indication of skin sensitisation

Any other information on results incl. tables

Challenge Phase: The 10% formulation of the hydrolysis product in acetone applied to 20 sites induced one moderate and 19 slight dermal reactions at the 24-hour observation. Only six sites displayed slight reactions at the 48-hour evaluation. On the vehicle (acetone) control sites, 12 had slight reactions at 24-hours post-exposure and a single site had a slight reaction present at 48 hours. For the Negative Control-I Group animals, the 10% hydrolysis product solution induced six slight dermal reactions at both the 24 and 48-hour observation. Two of the vehicle control sites on the Negative Control-I Group animals were noted with slight dermal reactions at the 24-hour observation. All irritation completely subsided by 48 hours. The positive control material, 0.1% dinitrochlorobenzene (DNCB), induced six slight, two moderate and two severe reactions at 24 hours after challenge dosing. By 48 hours, the responses had increased to two slight, six moderate and Mo severe reactions. In addition, eschar was present at all sites at 48 hours post-exposure. Yellow staining was observed for all positive control sites at both 24 and 48 hours. There were no skin reactions present on the vehicle control animals treated with 80% ethanol.

Rechallenge Phase: There were 20 very slight reactions for Test Group guinea pig sites rechallenged with 10% hydrolysis product in acetone at 24 hours. By 48 hours, the number so affected had fallen to eight. Fifteen very slight reactions were observed for sites rechallenged with 100% acetone. Irritation completely subsided for all sites dosed with 100% acetone by 48 hours post-exposure. All sites rechallenged with 10% hydrolysis product had slight reactions noted at 24 hours for the Negative Control-Il Group. Seven of the ten sites had slight dermal reactions at the 48-hour observation. Eight of the vehicle control sites on the Negative Control-II Group were noted with slight dermal reactions at 24 hours. Irritation completely subsided for all but two sites with slight reactions at 48 hours.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In the skin sensitisation study, conducted according to OECD Test Guideline 406 and in compliance with GLP, based on results obtained following challenge and rechallenge, the test material (hydrolysate) was found to be a not a skin sensitiser.

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