Sodium dibutyldithiocarbamate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Sodium dibutyldithiocarbamate

EC Number:

205-238-0

EC Name:

Sodium dibutyldithiocarbamate

Cas Number:

136-30-1

Molecular formula:

C9H19NS2.Na

IUPAC Name:

sodium (dibutylcarbamothioyl)sulfanide

Details on test material:

- Name of test material (as cited in study report): sodium dibutyldithiocarbamate (perkacit SDBC liq-w47%)
- Physical state: clear light yellow liquid
- Analytical purity: 46.20% (concentrated aqueous solution)
- Expiration date of the lot/batch: 19 April 2011 (allocated by NOTOX, 1 year after receipt of the test substance)
- Stability under test conditions: stable
- Storage condition of test material: at room temperature in the dark under nitrogen

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA-J

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: approx. 11 weeks old
- Weight at study initiation: within +/- 20% of the sex mean
- Housing: Individually in labeled Macrolon cages (MI type; height 12.5 cm) containing sterilized sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France). Paper (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom) was supplied as cage-enrichment. The paper was removed on Day 1 prior to dosing and was supplied again after scoring of the ears on Day 3.
- Diet: pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany, ad libitum
- Water: tap water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.7– 22.9
- Humidity (%): 38-81
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

dimethylformamide

Concentration:

0, 10, 25 and 50% (of the substance as manufactured, i.e. 46.20% aqueous solution)

No. of animals per dose:

5 females/dose

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: the vehicle was selected based on trial formulations performed at NOTOX and on test substance data supplied by the sponsor
- Irritation: a preliminary irritation study was conducted in order to select the highest test substanceconcentration to be used in the main study. In principle, this concentration should be well tolerated systemically by the animals and may give moderate irritation (maximally grade 2 at the highest concentration.
Two test substance concentrations were tested; a 50% and 100% concentration. The highest concentration was the maximum concentration as required in the test guidelines (undiluted for liquids). After a single application of the test substance, the animal treated at 100% was found dead on Day 1 and no abnormalities were noted at necropsy. After 3 days of treatment, the animal at 50% showed no signs of systemic toxicity and the ears of this animal showed no severe irritation.
- Lymph node proliferation response: not determined

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response: Stimulation Index (SI) calculated for each group. If the results indicate a SI ≥ 3, the test substance may be regarded as a skin sensitizer, based on the test guideline and recommendations done by ICCVAM

TREATMENT PREPARATION AND ADMINISTRATION: the dorsal surface of both ears was epidermally treated (25 μL/ear) with the test substance
concentration, at approximately the same time per day. The concentrations were mixed thoroughly using a vortex mixer immediately prior to dosing. The control animals were treated the same as the experimental animals, except that the vehicle was administered instead of the test substance.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

EC3

Value:

27.8

Remarks on result:

other: in %

Results 2

Parameter:

SI

Value:

1.1

Test group / Remarks:

10%

Remarks on result:

other: 10%

Results 3

Parameter:

SI

Value:

2.4

Test group / Remarks:

25%

Remarks on result:

other: 25%

Results 4

Parameter:

SI

Value:

7.7

Test group / Remarks:

50%

Remarks on result:

other: 50%

Cellular proliferation data / Observations:

847, 929, 2063 and 6559 DPM for 0 (vehicle), 10, 25 and 50% test substance concentrations.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

Based on this result SDBC (47% aqueous solution) shall be considered as a skin sensitizer.

Executive summary:

In this Mouse LLNA the sensitization potential of Sodium dibutyldithiocarbamate (SDBC) (47% aqueous solution) was tested. The study was carried out based on the OECD guideline 429. Test substance concentrations selected for the main study were based on the results of a preliminary study. After a single application of the test substance, the animal treated with the 100% test substance concentration was found dead on Day 1 and no abnormalities were noted at necropsy. After 3 days of treatment, the animal at 50% showed no signs of systemic toxicity and the ears of this animal showed no severe irritation. In the main study, three experimental groups of five female CBA/J mice were treated with test substance concentrations of 10, 25 or 50% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (Dimethyl formamide). Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and pooled for each animal. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed. The activity was expressed as the number of Disintegrations Per Minute (DPM) and a stimulation index (SI) was subsequently calculated for each group.

 

Slight erythema of the ears was observed among animals treated at 25% and for all animals treated at 50%, but was considered not to have a toxicologically significant effect on the activity of the nodes. No erythema of the ears was observed for any of the animals at 10% or control animals and no oedema was observed in any of the animals examined. No mortality occurred and no symptoms of systemic toxicity were observed in the animals of the main study. Body weights and body weight gain of experimental animals remained in the same range as controls over the study period. Auricular lymph nodes of all animals treated at 50% were considered enlarged and auricular lymph

nodes of all control animals and animals at 10 and 25% were considered normal in size. No macroscopic abnormalities of the surrounding area were noted in any of the animals. Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 25 and 50% were 929, 2063 and 6559 DPM respectively. The mean DPM/animal value for the vehicle control group was 847 DPM. The SI values calculated for the 10, 25 and 50% concentrations of the solution were 1.1, 2.4 and 7.7 respectively. These results indicate that the test substance could elicit an SI ≥ 3. The data showed a dose-response and an EC3 value of 27.8% was calculated. Based on these results SDBC (47% aqueous solution) is a skin sensitizer.