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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1970
Report Date:
1970

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Internal BASF method was used
GLP compliance:
no
Remarks:
pre-dates GLP
Type of study:
skin painting test
Justification for non-LLNA method:
old study report from 1970

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 2,3,5-trimethylhydroquinone

In vivo test system

Test animals

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

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, open
Vehicle:
other: acetone
Concentration / amount:
Induction: 20% (2 applications); 50% (8 applications)
Challenge: 5%,
Rechallenge: 20%
Challengeopen allclose all
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

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
12
Group:
test group
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.
Key result
Reading:
rechallenge
Hours after challenge:
12
Group:
test group
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.
Key result
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.
Key result
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.
Key result
Reading:
1st reading
Hours after challenge:
12
Group:
positive control
Dose level:
5%
Remarks on result:
not measured/tested
Key result
Reading:
rechallenge
Hours after challenge:
12
Group:
positive control
Dose level:
20%
Remarks on result:
not measured/tested

Any other information on results incl. tables

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%.

Applicant's summary and conclusion

Interpretation of results:
Category 1 (skin sensitising) based on GHS criteria
Conclusions:
The test substance trimethylhydroquinone was sensitizing to guinea-pigs under the test conditions chosen resulting in a classification to cause sensitization by skin contact according to CLP.
Executive summary:

Under the above stated test conditions trimethylquinone causes degeneration of the tissue on repeated application of 1% and 10 % acetone solutions to the skin of guinea-pigs and also leads to sensitization of the skin. When applied as 20% and 50% solution in acetone, distinct tissue degeneration and slight sensitizing of the skin are observed.