Registration Dossier

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP, OECD N°406 Guideline

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): DIBENZYL TRITHIOCARBONATE
- Physical state: yellow orange-colored solid
- Analytical purity: 96.2
- Purity test date: 2003-10-27
- Lot/batch No.: 1 UG 114
- Expiration date of the lot/batch: November 2004
- Storage condition of test material: at room temperature and protected from light

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 2 months old
- Weight at study initiation: 380 ± 15 g for the males and 302 ± 13 g for the females
- Housing: individually in polycarbonates cages (48x27x20cm)
- Diet (e.g. ad libitum): ad libitum "106 pelleted diet" (U.A.R., 91360 Villemoisson-sur-Orge, France)
- Water (e.g. ad libitum): ad libitum drinking water filtered with a 0.22µ membrane (Société Millipore, 78140 Velizy, France)
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20+/-3°C
- Humidity (%): 50+/-20%
- Air changes (per hr): approx. 12
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
other: The vehicle used for intradermal injections was corn oil. For topical applications (induction phase and challenge application), the vehicle used was acetone.
Concentration / amount:
intradermal induction: 0.1 %
cutaneous induction: 50 %
cutaneous challenge: 25 %
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: The vehicle used for intradermal injections was corn oil. For topical applications (induction phase and challenge application), the vehicle used was acetone.
Concentration / amount:
intradermal induction: 0.1 %
cutaneous induction: 50 %
cutaneous challenge: 25 %
No. of animals per dose:
Control group: 5 males and 5 females
Treated group: 10 males and 10 females
Details on study design:
RANGE FINDING TESTS:
Tested concentrations:
Intradermal test: 10%, 5%, 2.5%, 1% and 0.1% (w/w)
Cutaneous test: 50% and 25% (w/w)

MAIN STUDY
A. INDUCTION EXPOSURE
* Intradermal induction:
- On day 1, 3injections are realized on the scapular area:
- 0.1mL of Freund's complete adjuvant at 50% in 0.9%NaCl
- 0.1mL of the test item at 0.1 % (for treated group) or 0.1mL of vehicle (for control group)
- 0.1mL of a mixture 50/50 (V/V) of Freund's complete adjuvant in 0.9% NaCl and the test item at 0.1 % (for treated group) or the vehicle (for control group).

* Cutaneous induction:
- On day 7, local irritation is induced by application of Sodium Laurylsulfate 10% in Vaseline
- On day 8, occlusive application on the scapular area of 0.5mL of the test item 50% (for treated group) or vehicle (for control group) for 48hours

B. CHALLENGE EXPOSURE D22
On day 22, 24hours occlusive application on the scapular area of 0.5mL of the test item 25% on the right flank and 0.5mL of the vehicle on the left flank.
Reactions are evaluated 24 and 48 hours after removal of the dressing
Challenge controls:
No
Positive control substance(s):
yes
Remarks:
Mercaptobenzothiazole (CIT/Study No. 26182 RDG - September 2003)

Results and discussion

Positive control results:
Mercaptobenzothiazole : Positive result in recent study on 10/10 females. Induction: test substance injected intradermally 1.0 (d1) and applied cutaneously 20% (d8). Challenge (d22): 20% r flank 0.5% l flank

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0.5 ml of a 25% solution
No. with + reactions:
2
Total no. in group:
10
Clinical observations:
discrete erythema (grade 1)
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 0.5 ml of a 25% solution. No with. + reactions: 2.0. Total no. in groups: 10.0. Clinical observations: discrete erythema (grade 1).
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0.5 ml of a 25% solution
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 0.5 ml of a 25% solution. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
0.5 ml of a 25% solution
No. with + reactions:
19
Total no. in group:
20
Clinical observations:
a discrete or moderate erythema (grade 1 or 2)
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 0.5 ml of a 25% solution. No with. + reactions: 19.0. Total no. in groups: 20.0. Clinical observations: a discrete or moderate erythema (grade 1 or 2).
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
0.5 ml of a 25% solution
No. with + reactions:
9
Total no. in group:
20
Clinical observations:
a discrete or moderate erythema (grade 1 or 2)
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 0.5 ml of a 25% solution. No with. + reactions: 9.0. Total no. in groups: 20.0. Clinical observations: a discrete or moderate erythema (grade 1 or 2).

Any other information on results incl. tables

A discrete erythema (grade 1) was observed in 2/10 animals of the control group, at the 24-hour reading only.

In the treated group, a discrete or moderate erythema (grade 1 or 2), together with an oedema in one animal, was noted at the 24-hour reading in 17/20 and 2/20 animals, respectively. At the 48-hour reading, a discrete or moderate erythema (grade 1 or 2), together with dryness of the skin in two animals, persisted in 7/20 and 2/20 animals, respectively.

The persistent cutaneous reactions observed in 9/20 animals of the treated group were attributed to delayed contact hypersensitivity.

Applicant's summary and conclusion

Interpretation of results:
sensitising
Remarks:
Migrated information
Conclusions:
DIBENZYL TRITHIOCARBONATE induces delayed contact hypersensitivity in 9/20 (45%) guinea pigs, and should therefore be considered as a moderate sensitizer
Executive summary:

The delayed contact hypersensivity of DIBENZYL TRITHIOCARBONATE was evaluated in Guinea pigs according to OECD N°406 guideline (Magnusson and Kligman test).

The induction phase has been realized both by intradermal route on day 0.1 (% in vehicle) and by cutaneous route on day 50 (%) in 2 groups of guinea pigs: 5 males and 5 females for control group and 10 males and 10 females for treated group. The challenge phase was realized on day 22 by cutaneous application of 25 % on the right flank (vehicle on the left flank); the cutaneous reactions were scored 24 and 48 hours after the challenge phase.

After the challenge application, a discrete erythema was observed in 2/10 animals of the control group, at the 24-hour reading only.

In the treated group, a discrete or moderate erythema, together with an oedema in one animal, was noted at the 24-hour reading in 17/20 and 2/20 animals, respectively. At the 48-hour reading, a discrete or moderate erythema, together with dryness of the skin in two animals, persisted in 7/20 and 2/20 animals, respectively. The persistent cutaneous reactions observed in 9/20 animals of the treated group were attributed to delayed contact hypersensitivity.

Under the experimental conditions of the maximization method of Magnusson and Kligman, DIBENZYL TRITHIOCARBONATE induces delayed contact hypersensitivity in 9/20 (45%) guinea pigs, and should therefore be considered as a moderate sensitizer.