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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011-05-31 - 2011-07-12
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-study
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
mouse local lymph node assay (LLNA)
Species:
mouse
Strain:
CBA
Sex:
female
Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
2.5, 5, 10, 25 %
No. of animals per dose:
4
Details on study design:
In the main assay 24 female CBA/Ca mice were allocated to six groups of four animals each:

- four groups received 3-Methylpyrazol at four different concentrations of 25 %, 10 %, 5 % or 2.5 %,

- the negative control group received the vehicle (AOO),

- the positive control groups received a-Hexylcinnamaldehyde (HCA) at concentration of 25 %.

Each substance was applied on the external surface of each ear (25 ^L/ear) of the animals for three consecutive days (Day 1, 2 and 3). There was no treatment on Days 4, 5 and 6. On Day 6, the cell proliferation in the local lymph nodes was measured by incorporation of tritiated methyl thymidine (3HTdR) and the obtained values were used to calculate stimulation indices (SI).
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Test Group

Measured

Group*

DPN

Stimulation

Name

DPM/group

DPM

(DPM/Node)

Index Values

Negative (vehicle) control:

5088

5038.5

629.8

1.0

AOO

 

 

 

 

Positive control

37158

37108.5

4638.6

7.4

25 %HCA in AOO

 

 

 

 

3-Methylpyrazol

-

-

-

-

25 %in AOO

 

 

 

 

3-Methylpyrazol

8887

8837.5

1104.7

1.8

10 %in AOO

 

 

 

 

3-Methylpyrazol

9676

9626.5

1203.3

1.9

5 %in AOO

 

 

 

 

3-Methylpyrazol

8151

8101.5

1012.7

1.6

2.5 %in AOO

 

 

 

 

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
In conclusion, under the conditions of the present assay 3-Methylpyrazol, tested at the maximum feasible concentration of 10 % and concentrations of 5 % and 2.5 % as formulations in a suitable vehicle (AOO), was shown to have no sensitization potential (non-sensitizer) in the Local Lymph Node Assay.
Executive summary:

In conclusion, under the conditions of the present assay 3-Methylpyrazol, tested at the maximum feasible concentration of 10 % and concentrations of 5 % and 2.5 % as formulations in a suitable vehicle (AOO), was shown to have no sensitization potential (non-sensitizer) in the Local Lymph Node Assay.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

The available study is GLP-compliant and has Klimisch score 1.


Migrated from Short description of key information:
3-Methylpyrazol, tested at the maximum feasible concentration of 10 % and concentrations of 5 % and 2.5 % as formulations in a suitable vehicle (AOO), was shown to have no sensitization potential (non-sensitizer) in the Local Lymph Node Assay.

Justification for selection of skin sensitisation endpoint:
Only one study available.

Justification for classification or non-classification

3 -Methylpyrazole has not to be classified as skin sensitiser.