Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1970
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Meets generally accepted scientific standards, well documented and acceptable for assessment; pre-GLP study.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Guinea Pig induction method, company protocol
GLP compliance:
no
Type of study:
skin painting test
Species:
guinea pig
Strain:
not specified
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: mean 441.2 g
Route:
epicutaneous, open
Vehicle:
other: acetone
Concentration / amount:
Induction: 20% (2 applications); 50% (8 applications)
Challenge: 5%,
Rechallenge: 20%
Route:
epicutaneous, open
Vehicle:
other: acetone
Concentration / amount:
Induction: 20% (2 applications); 50% (8 applications)
Challenge: 5%,
Rechallenge: 20%
No. of animals per dose:
10
Details on study design:
MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 10 applications
- Test groups: 10 animals
- Control group: 3 animals
- Site: ca. 25 cm2 clipped area of flank
- Frequency of applications: paintings were done three times in a row, for 5 days per week (together ten times in two weeks)
- Concentrations: 20% (2 applications), 50% (8 applications)


B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: first challenge 16 days after induction; second challenge 16 days after first challenge
- Test groups: 10 animals
- Control group: 3 animals
- Site: shaved right flank
- Concentrations: 5% (challenge), 20% (rechallenge)
- Evaluation (hr after challenge): 12 h
Challenge controls:
Not treated during induction period
Positive control substance(s):
not specified
Reading:
1st reading
Hours after challenge:
12
Group:
test chemical
Dose level:
5%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 12.0. Group: test group. Dose level: 5%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
rechallenge
Hours after challenge:
12
Group:
test chemical
Dose level:
20%
No. with + reactions:
7
Total no. in group:
10
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 12.0. Group: test group. Dose level: 20%. No with. + reactions: 7.0. Total no. in groups: 10.0.
Reading:
1st reading
Hours after challenge:
12
Group:
negative control
Dose level:
5%
No. with + reactions:
0
Total no. in group:
3
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 12.0. Group: negative control. Dose level: 5%. No with. + reactions: 0.0. Total no. in groups: 3.0.
Reading:
rechallenge
Hours after challenge:
12
Group:
negative control
Dose level:
20%
No. with + reactions:
0
Total no. in group:
3
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 12.0. Group: negative control. Dose level: 20%. No with. + reactions: 0.0. Total no. in groups: 3.0.
The test substance was judged to be slightly sensitizing by the authors.

1) Induction:
Repeated application of the test substance at 20% or 50% in acetone produced hemorrhagic encrustations in 10/10 animals of the test group. These symptoms were reversible within the 16-day rest period.

2) Challenge / rechallenge:
Single application of the 5% solution in acetone to the previously untreated site did not produce any skin response in the animals of the test group. In contrast, application of the 20% solution at 16 days later produced a slight erythema in 7/10 test animals. Control animals did not show any skin response after treatment with either 5% or 20%.
Interpretation of results:
sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

The experimental data for hydroquinone is not provided. It is referred to the legal classification of hydroquinone in the EU (Annex I index no. 604 -005 -00 -4).


Migrated from Short description of key information:
Both trimethylhydroquinone (CAS 700-13-0) and hydroquinone (CAS 123-31-9) cause skin sensitization in experimental animals. Therefore, 2-methylhydroquinone is classified for skin sensitization without further testing.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification