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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study following a method equivalent to a recognised guideline with acceptable deviations.
Cross-reference
Reason / purpose:
read-across: supporting information

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report Date:
1985

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
yes
Remarks:
Only 10 animals used within the study, guideline recommends 20.
Principles of method if other than guideline:
Method employed in this study for the detection of delayed contact hypersensitivity was the guinea-pig test described by Buehler, E.V., Arch. Dermatol. 91, 171, (1965) and updated by Buehler, E.V. and Ritz, H.L., Current Concepts in Cutaneous Toxicity, pp. 215-40, (1980). Applicant accessment indicates that the scoring appears consistent with: Buehler, E.V. and Griffin F. Animal Models Dermatol., 55, (1975)
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
The test was conducted prior to 11 October 2016 as stated under Commission Regulation (EU) 2016/1688 and is used by read-across and as part of a Weight of Evidence adaptation under Regulation (EC) 1907/2006: Annex XI: section 1.5 read-across and Annex XI: section 1.2 weight of evidence.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid
Details on test material:
- Physical state: Liquid
- Other: clear yellow

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Recognised supplier
- Weight at study initiation: 417 - 460g (test group); 392-480g (control)
- Housing: In groups of five in grid bottomed polypropylene cages
- Diet (e.g. ad libitum): vitamin-C enriched pelleted diet ad libitum
- Acclimation period: 17 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17- 25°C
- Humidity (%): Not reported.
- Air changes (per hr): Air conditioned room (air changes not reported).
- Photoperiod (hrs dark / hrs light): 12 hours light / 12 hours dark

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
other: ethanol
Concentration / amount:
Preliminary irritation testing: topical (occlusive): 12.5, 25, 50%v/v (ethanol) and 100% (undiluted)
Induction: - Topical: 100% (undiluted)
Challenge: - Topical: 100% (undiluted) and 50%v/v (ethanol)
Adequacy of induction:
highest technically applicable concentration used
Challenge
Route:
epicutaneous, occlusive
Vehicle:
other: ethanol
Concentration / amount:
Preliminary irritation testing: topical (occlusive): 12.5, 25, 50%v/v (ethanol) and 100% (undiluted)
Induction: - Topical: 100% (undiluted)
Challenge: - Topical: 100% (undiluted) and 50%v/v (ethanol)
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
Test group: 10
Details on study design:
RANGE FINDING TESTS:
Preliminary Investigations: The intradermal and topical irritancy of a range of dilutions of the test substance was investigated.Four concentrations of the test material (100%, 50%, 25% and 12.5%) were used. The dilutions were prepared using ethanol. Each concentration was applied to one of four sites. The results of this dose ranging study indicated that the undiluted material was unlikely to act as a primary irritant at up to 100% (undiluted) concentration.

MAIN STUDY
A. INDUCTION EXPOSURE
Topical induction: A 0.5ml aliquot of neat test substance dorsal area was applied to the clipped left shoulder for 6 hours under occlusion (a 20mm square of surgical lint covered with surgical tape and elastic adhesive). Induction applications were made on days 1, 8 and 15. Controls were treated with ethanol vehicle only. This dosing procedure was repeated at weekly intervals on days eight and fifteen.

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: On day 28 of the study, 6-hour occluded challenge applications were made to the right flank with 50%v/v and 100% (undiluted) test item using (a 20mm square of surgical lint covered with surgical tape and elastic adhesive).
- Exposure period: 6 hours
- Test groups: 100% and 50%v/v
- Control group: 0% (vehicle only)
- Evaluation (hr after challenge): 24 and 48 hours.
Challenge controls:
Previously naive test group (treated only with vehicle) was treated with the test item as a challenge control at 50%v/v (in ethanol) and 100% (undiluted).
Positive control substance(s):
no

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No significant clinical signs, all gained bodyweight
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No significant clinical signs, all gained bodyweight.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No significant clinical signs, all gained bodyweight
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No significant clinical signs, all gained bodyweight.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No significant clinical signs, all gained bodyweight
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No significant clinical signs, all gained bodyweight.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No significant clinical signs, all gained bodyweight
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 50%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No significant clinical signs, all gained bodyweight.

Any other information on results incl. tables

Table 1. Dermal reactions elicited in challenge application

Group

 

100%

 

50%

 

 

No. +ve reactions

 

 

24 hour

48 hour

24 hour

48 hour

 

 

Test

1*

0

0

0

0

 

0

 

2

0

0

0

0

 

0

 

3

0

0

0

0

 

0

 

4

0

0

0

0

 

0

 

5

0

0

0

0

 

0

 

6

0

0

0

0

 

0

 

7

0

0

0

0

 

0

 

8

0

0

0

0

 

0

 

9

0

0

0

0

 

0

 

10

0

0

0

0

 

0

Control

11

0

0

0

0

 

0

 

12

0

0

0

0

 

0

 

13

0

0

0

0

 

0

 

14

0

0

0

0

 

0

 

15

0

0

0

0

 

0

 

16

0

0

0

0

 

0

 

17

0

0

0

0

 

0

 

18

0

0

0

0

 

0

 

19

0

0

0

0

 

0

 

20

0

0

0

0

 

0

* Due to a technical error number 1 - occlusive dressing remained in position for 24 hours rather than 6 hours.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Under the conditions of this study used, the test material is not considered to be a contact sensitizer.
Executive summary:

The study was performed according to a method equivalent to guideline OECD TG 406 consistent with Buehler method under GLP to assess the skin sensitisation potential of the test substance. The study was conducted using a preliminary irritation screen, an induction phase and a challenge phase. Preliminary irritation testing was for use in the induction phases of the study and the challenge phase of the study. Two groups, each of ten animals, were used for the study which was divided into an induction stage and a challenge stage. The induction stage consisted of three topical applications of the test material to the left shoulder of each of the ten test animals. These applications were made on Days one, eight and fifteen and each application lasted for six hours. Fourteen days after completion of the induction stage, all animals were challenged with two concentrations of the test material that had shown no evidence of irritation during the dose ranging study. No visible response was exhibited by any animal of the test or control group when challenged with the undiluted material and a 50% concentration of the material in ethanol. Under the conditions of this study, the test substance is not considered to be a contact sensitizer.