N,N''-(methyl-m-phenylene)bis[N',N'-dimethylurea]

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001-04-02 to 200105-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

study was already performed in 2001 and is sufficient for non-classification

Test material

Test material information

Constituent 1

Reference substance name:

N,N''-(4-methyl-m-phenylene)bis[N',N'-dimethylurea]

EC Number:

241-523-6

EC Name:

N,N''-(4-methyl-m-phenylene)bis[N',N'-dimethylurea]

Cas Number:

17526-94-2

Molecular formula:

C13H20N4O2

IUPAC Name:

3-[3-(dimethylcarbamoylamino)-4-methylphenyl]-1,1-dimethylurea

impurity 1

Reference substance name:

3-[3-(dimethylcarbamoylamino)-2-methylphenyl]-1,1-dimethylurea

Cas Number:

17607-23-7

Molecular formula:

C13H20N4O2

IUPAC Name:

3-[3-(dimethylcarbamoylamino)-2-methylphenyl]-1,1-dimethylurea

impurity 2

Reference substance name:

unknown

IUPAC Name:

unknown

impurity 3

Reference substance name:

Water

EC Number:

231-791-2

EC Name:

Water

Cas Number:

7732-18-5

Molecular formula:

H2O

IUPAC Name:

water

Test material form:

solid

Specific details on test material used for the study:

- Substance type: organic
- Physical state: colourless solid
- Analytical purity: 100%
- Purity test date: 01 March 2000
- Lot/batch No.: 0232 07
- Expiration date of the lot/batch: March 2003
- Storage condition of test material: store dry in closed containers
- Other: stable at dry storage conditions for at least 2 years

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelmann GmbH, D-33178 Borchen
- Age at study initiation: no data
- Weight at study initiation: 300- 500 g
- Housing: The animals were barrier maintained (semi-barrier) in air conditioned rooms and were kept in groups in Terluran-cages on Altromin saw fiber bedding. Max. group size 10 animals
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: adequate

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3° C
- Humidity (%): 55±10%
- Air changes (per hr): 10x/hour
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

5 % / 0.1 ml

Day(s)/duration:

7 d

Adequacy of induction:

highest technically applicable concentration used

Induction 2

Route:

epicutaneous, occlusive

Vehicle:

petrolatum

Concentration / amount:

25 % / 0.5 ml

Day(s)/duration:

48 h

Adequacy of induction:

non-irritant substance, but skin pre-treated with 10% SDS

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

petrolatum

Concentration / amount:

25 % / 0.5 ml

Day(s)/duration:

24 h

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

10 female test animals, 5 female control animals and 6 female animals for range finding

Details on study design:

RANGE FINDING TESTS: For the justification of dose levels a preliminary test as performed. Three animals were treated intradermally with 0.5%, 1%, 2.5%, 5% concentration ofthe test item and three animals were topically treated with 5%, 10%, 25% concentration of the test item.

MAIN STUDY
A. INDUCTION EXPOSURE
Three pairs of intradermal injections of 0.1 ml volume were given in the shoulder region which was cleared of hair so that one of each pair lies on each side of the midline.
- No. of exposures: 3
Induction: First Stage, Intradermal Injection
Test group: Day 0
Injection 1: Freund's Adjuvant complete, 1+1 (v/v) diluted with isotonic saline
Injection 2: Prepared test item
Injection 3: Prepared test item at a concentration of 50% (VN) in Freund's
Adjuvant complete, 1+1 (v/v) diluted with isotonic saline.

Control group : Day 0
Injection 1: Freund's Adjuvant complete, 1+1 (v/v) diluted with isotonic saline
Injection 2: NaCl 0,9%
Injection 3: NaCl 0,9% at a concentration of50% (VIV) in Freund's
Adjuvant complete, 1+1 (v/v) diluted with isotonic saline.

lnduction: Second Stage, Topical Application
Day 6: Test and control group
Approximately twenty-four hours before the topical induction application the test area, after close clipping was painted with 0.5 ml of 10% sodium lauryl sulfate in vaseline, in order to create a local irritation.

Test Group: Day 7
A patch was loaded with 0.5 ml of the test item at a 25% concentration, applied to the test area and held in contact by an occlusive dressing for 48 hours.
Control Group: Day 7
A patch was loaded with 0.5 ml of vehicle and applied to the test area and held in contact by an occlusive dressing for 48 hours.

- Exposure period: 7 days
- Test groups: 1
- Control group: 1
- Site: shoulder region

B. CHALLENGE EXPOSURE: topiccal application
- No. of exposures: 1
- Day(s) of challenge: 1
- Exposure period: 24 h
- Test groups: 1
- Control group: 1
- Site: flanks
- Concentrations: A patch loaded with 0.5 ml of the test item (25%) was applied to the left flank of the animals and, a patch loaded with 0.5 ml vehicle to the right flank (intraspecific control), respectively. The patches were held in contact by an occlusive dressing for 24 hours. At the end of the challenge skin was cleaned with the aid of moistened ganze patches.
- Evaluation (hr after challenge): 24 h, 48 h and 72 h
Approximately 21 hours after removing the patch the challenge area was cleaned and cleared of hair. Approximately 24 hours after removing of the patch the skin reaction was observed and recorded according to the grades shown below. Two more observations were recorded 48 and 72 hours after patch removal.

Challenge controls:

0.5 ml of the vehicle was applied to the right flank (intraspecific control).

Positive control substance(s):

yes

Remarks:

Mercaptobenzothiazole

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

25 %

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Results 2

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

25%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Results 3

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

25%

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Results 4

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

25%

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

none

Remarks on result:

no indication of skin sensitisation

Results 5

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

2 % induction I; 25 % induction II: 15 % challenge

No. with + reactions:

7

Total no. in group:

10

Clinical observations:

Erythema Grade 1 + 2; Oedema Grade 1

Remarks on result:

positive indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Considering the reported data of this sensitization test it can be stated that the test item TDI-Urone caused no reactions identified as sensitization.

Executive summary:

In a dermal sensitization study according to OECD 406 with TDI urone in 0.9%NaCl (5% TDI-Urone) and Vaseline (25% TDI-Urone), respectively, Hsd Poc:DH guinea pigs (10 females in the test group, 5 females in the control group and 6 females for range-finding study) were tested using the method of Guinea-Pig Maximisation Test.

During the induction phase the guinea pigs were intradermally injected with 5% TDI-Urone and, after treatment with sodium lauryl sulfate, topically treated with 25%TDI-Urone. After a latency of 2 weeks the animals were challenged with 25% TDI-Urone on the flank. The grade of skin reactions was compared to control animals, which were treated with isotonic saline resp. vaseline during the induction phase and, during the challenge phase with the test item, respectively.

No skin reactions were observed throughout the study. Therefore, the skin sensitization rate after application of TDI-Urone was 0 %. Under the test conditions TDI-Urone showed no sensitizing properties. Animals of the test group showed normal weight gain as compared to historical data and the animals of the control group.

In this study, TDI-Urone is not a dermal sensitizer.