Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July 3, 1990 - September 27, 1990
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report date:
1991

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
(1981)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Version / remarks:
(1984)
Deviations:
no
Principles of method if other than guideline:
"Experimental Skin Sensitization in the Guinea pig and Man", Buehler E.V. and Griffith F. in: Animal models in dermatology (ed. H.I. Maibach), pp. 56-66, Edinburgh, Churchill Livingstone, 1975.
GLP compliance:
yes (incl. QA statement)
Type of study:
Buehler test
Justification for non-LLNA method:
The LLNA method was adopted in 2002.

Test material

Constituent 1
Reference substance name:
A mixture (1:2:1) of: bis(N-cyclohexyl-N'-phenyleneureido)methylene; bis(N-octadecyl-N'-phenyleneureido)methylene; bis(N-dicyclohexyl-N'-phenyleneureido)methylene
EC Number:
406-550-1
EC Name:
A mixture (1:2:1) of: bis(N-cyclohexyl-N'-phenyleneureido)methylene; bis(N-octadecyl-N'-phenyleneureido)methylene; bis(N-dicyclohexyl-N'-phenyleneureido)methylene
IUPAC Name:
Reaction mass (1:2:1) of bis(N-cyclohexyl-N'-phenyleneureido)methylene and bis(N-octadecyl-N'-phenyleneureido)methylene and bis(N-dicyclohexyl-N'-phenyleneureido)methylene
Details on test material:
- Name of test material (as cited in study report): MDI/CHA/ODA/DCHA
- Description: White yellowish solid
- Storage condition of test material: At room temperature in the dark

In vivo test system

Test animals

Species:
guinea pig
Strain:
Himalayan
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: BRL Ltd., Basel, Switzerland
- Age at study initiation: Approx. 10 weeks
- Weight at study initiation: 313 - 411 grams
- Housing: Group housing of 2 animals per cage with wire-mesh floors
- Diet: Free access to standard guinea pig diet, including ascorbic acid (LC 23-B, pellet diameter 4 mm, Hope Farms, Woerden, The Netherlands)
- Water: Free access to tap-water, diluted with decalcified water
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21
- Humidity (%): 55
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES (main study): From: August 27, 1990 To: September 27, 1990

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
- 50% for the induction
- 25% for the challenge
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
corn oil
Concentration / amount:
- 50% for the induction
- 25% for the challenge
No. of animals per dose:
Test animals: 20; Control: 10
Details on study design:
RANGE FINDING TESTS
One animal was treated epicutaneously at the shaved left flank with 0.5 mL of a 50% concentration of the test substance in corn oil using a Metalline patch (Lohman, Germany) mounted on Micropore tape (3M, USA) and held in place with Coban elastic bandage (3M, USA). After 24 hours, the dressings and residual test substance were removed using a tissue moistened with tap-water. The treated skin was assessed for erythema and oedema, 24 and 48 hours after bandage removal. Four further animals were shaved on the left flank and exposed to 0.05 mL of 50%, 25%, 10% and 5% (w/w) concentrations of the test substance in corn oil, occlusively administered by means of Square chambers (v.d. Bend, The Netherlands) mounted on Micropore tape. The bandage was fixed in place by means of Coban elastic bandage. After 24 hours, the dressings and residual test substance were removed using a tissue moistened with tap-water. The reaction sites were assessed for erythema and oedema, 24 and 48 hours after bandage removal. Immediately after the 24 hours skin reading, the treated areas were re-shaved.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 9 applications during a period of 3 weeks (days 1, 3, 5, 8, 10, 12, 15, 17 and 19).
- Exposure period: 6 hours per application. After each application, the remaining test substance was also removed with a tissue moistened with tap-water.
- Test groups: 1
- Control groups: 1
- Site: scapula region (left side), after clipping
- Patch: Metalline (2 x 3 cm)
- Concentration: 50% in corn oil (test group); corn oil (control group) (0.5 mL)
- Scoring: The treated skin area of the test group and of the control group was scored immediately after removal of the dressings on day 19.

B. CHALLENGE EXPOSURE
- Day(s) of challenge: 10 days after the last induction (day 29)
- Exposure period: 6 hours. After the application, the remaining test substance was also removed with a tissue moistened with tap-water.
- Test groups: 1
- Control groups: 1
- Site: right flank, after clipping and shaving a 5 x 5 area.
- Patch: Metalline (2 x 3 cm)
- Concentrations (2 patches/animal):
-- 25% in corn oil (test and control group) (0.5 mL)
-- corn oil (test and control group) (0.5 mL)
- Evaluation (hr after challenge): 24 and 48 hours after removal of the dressings
Positive control substance(s):
no
Remarks:
(a reliability check is carried out at regular intervals to check the sensitivity of the test system)

Results and discussion

Positive control results:
The latest reliability check was carried out in April 1990 using formaldehyde. In this study, a sensitisation rate of 35% was found, showing that the test system is reliable.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Group:
positive control
Dose level:
25% (w/w)
No. with + reactions:
7
Total no. in group:
20
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25% (w/w)
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
25% (w/w)
No. with + reactions:
0
Total no. in group:
9
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25% (w/w)
No. with + reactions:
2
Total no. in group:
20
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25% (w/w)
No. with + reactions:
6
Total no. in group:
20
Remarks on result:
positive indication of skin sensitisation

Any other information on results incl. tables

RANGE FINDING TESTS

- In the animal treated with 0.5 mL of a 50% concentration, slight erythema was observed, 24 and 48 hours after bandage removal.

- In one other animal, treated with 0.05 mL of a 50% concentration, slight erythema was observed, 24 hours after bandage removal.

- No skin reactions were observed at 25, 10 and 5%.

- Based on these results, 50% was choosen for induction (highest concentration possible for a solid) and 25% for challenge (as erythema was observed at 50% and not at 25%).

MAIN STUDY
- Signs of irritation during induction: 1 animal of the test group showed slight erythema and scaliness after the last application. This animal subsequently indicated sensitisation. Scaliness was observed in other animal during the induction period; this animal did not subsequently indicated sensitisation.

- Six animals of the test group showed positive reactions. The positive reactions observed in the test group were characterised by spotted to confluent redness and scaliness.

- Vehicle group: No positive skin reactions after challenge


OTHER OBSERVATIONS

- No symptoms of systemic toxicity were observed in the animals

- One animal of the control group was found dead during the 1st induction application (day 1), possibly due to stress

- The average body weight gain of experimental and control animals was similar

Applicant's summary and conclusion

Interpretation of results:
other: Sensitising according to Regulation (EC) No. 1272/2008.
Conclusions:
Based on the results of a Buehler test performed according to OECD 406 (1981), the substance needs to be classified as a skin sensitiser (sub-category 1B).
Executive summary:

The skin sensitisation potential of the substance (a solid) was investigated by performing a Buehler test in accordance with OECD 406 (1981) and according to GLP principles. Corn oil was used as vehicle. Test substance concentrations selected for the main study were based on the results of a preliminary study. Reliable positive and negative controls were included.A concentration of 50% was used for the induction (max. attainable concentration) and 25% for the challenge. Six of the 20 test group animals showed sensitisation effects after challenge, resulting therefore in a sensitization rate of 30% in this non adjuvant-type test. As this is ≥15%, the substance needs to be classified as a skin sensitiser in accordance with the CLP Regulation (sub-category 1B).