Carbonotrithioic acid, bis(phenylmethyl) ester

Skin sensitisation

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The study was performed before the implementation of the REACH regulation.

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

460-390-7

EC Name:

-

Cas Number:

26504-29-0

Molecular formula:

C15H14S3

IUPAC Name:

bis(benzylsulfanyl)methanethione

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)

Induction

Induction 1

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.

Induction 2

Concentration / amount:

intradermal induction: 0.1 %
cutaneous induction: 50 %
cutaneous challenge: 25 %

Challenge

Challenge 1

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.

Challenge 2

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)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0.1%

No. with + reactions:

2

Total no. in group:

10

Clinical observations:

discrete erythema (grade 1)

Remarks on result:

no indication of skin sensitisation

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0.1%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.1%

No. with + reactions:

19

Total no. in group:

20

Clinical observations:

a discrete or moderate erythema (grade 1 or 2)

Remarks on result:

positive indication of skin sensitisation

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.1%

No. with + reactions:

9

Total no. in group:

20

Clinical observations:

a discrete or moderate erythema (grade 1 or 2)

Remarks on result:

positive indication of skin sensitisation

Results 5

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

1%

No. with + reactions:

10

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Results 6

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

1%

No. with + reactions:

10

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

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:

Category 1B (indication of skin sensitising potential) based on GHS criteria

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.