1-Piperazinecarboxylic acid, 4-(6-amino-3-pyridinyl)-, 1,1-dimethylethyl ester

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Feb - May 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

tert-butyl 4-(6-aminopyridin-3-yl)piperazine-1-carboxylate

Cas Number:

571188-59-5

Molecular formula:

C14H22N4O2

IUPAC Name:

tert-butyl 4-(6-aminopyridin-3-yl)piperazine-1-carboxylate

Test material form:

solid: bulk

In vivo test system

Test animals

Species:

mouse

Strain:

Balb/c

Sex:

female

Details on test animals and environmental conditions:

Number of animals 30 females (nulliparous and non-pregnant), six females per group.
Age: Approximately 8 weeks (at initiation of treatment).
Body weight range: 18 to 21 gram (at initiation of treatment).

Study design: in vivo (LLNA)

Vehicle:

other: Ethanol/water (7/3, v/v)

Concentration:

Concentrations:
vehicle control Ethanol/water (7/3, v/v),
positive control DNCB (1-Chloro-2,4-Dinitrobenzene): 0.5% (w/w),
and LEE011-A2: 50%, 5%, 0.5% (w/w).
The formulations appeared visually as clear solutions.

No. of animals per dose:

Three groups of six animals were treated with one test item concentration per group. The highest test item concentration was selected from the pre-screen test. One group of six animals was treated with vehicle and one group with the positive control item.

Details on study design:

In the main study, six Balb/c female mice per group received topical test or control items on the dorsum of both ears once a day on 3 consecutive days. Auricular lymph nodes were taken 24 hours after the last application. Endpoints: visual examination ears and sizes ear-draining lymph nodes, body weight at treatment start and day of necropsy, ear weight (skin irritation), ear-draining lymph node weights and cell counts (LN hyperplasia).
Concentrations:
vehicle control Ethanol/water (7/3, v/v),
positive control DNCB (1-Chloro-2,4-Dinitrobenzene): 0.5% (w/w),
and LEE011-A2: 50%, 5%, 0.5% (w/w).
The formulations appeared visually as clear solutions.

Positive control substance(s):

other: 0.5% 1-Chloro-2,4-Dinitrobenzene (DNCB)

Statistics:

Calculations were performed in MS EXCEL and statistical analysis was performed with GraphPad Prism 4 (Kruskal-Wallis test, followed by the Mann Whitney test).

Results and discussion

Positive control results:

The positive control item DNCB elicited a reaction pattern with increased LN hyperplasia, which was in congruence with the expected mode of action of a contact allergen.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

other: Ear weight index

Value:

ca. 1.03

Test group / Remarks:

0.5%

Results 2

Key result

Parameter:

other: LN weight index

Value:

ca. 1.15

Test group / Remarks:

0.5%

Results 3

Key result

Parameter:

other: Cell count index

Value:

ca. 1.22

Test group / Remarks:

0.5%

Results 4

Key result

Parameter:

SI

Test group / Remarks:

0.5%

Remarks on result:

not measured/tested

Results 5

Key result

Parameter:

other: Ear weight index

Value:

ca. 1.01

Test group / Remarks:

5%

Results 6

Key result

Parameter:

other: LN weight index

Value:

ca. 1.17

Test group / Remarks:

5%

Results 7

Key result

Parameter:

other: Cell count index

Value:

ca. 1.42

Test group / Remarks:

5%

Results 8

Key result

Parameter:

SI

Remarks on result:

not measured/tested

Results 9

Key result

Parameter:

other: Ear weight index

Value:

ca. 0.97

Test group / Remarks:

50%

Results 10

Key result

Parameter:

other: LN weight index

Value:

ca. 1.33

Test group / Remarks:

50%

Results 11

Key result

Parameter:

other: Cell count index

Value:

ca. 2.01

Test group / Remarks:

50%

Applicant's summary and conclusion

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

In conclusion, LEE011-A2 appeared to be a weak sensitizer without irritating potential in the murine LLNA TIER I.
Based on these results:
according to the recommendations made in the test guidelines (including all amendments), LEE011-A2 would be regarded as skin sensitizer.
- according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2011) (including all amendments), LEE011-A2 should be classified as skin sensitizer (Category 1B).
- according to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments), LEE011-A2 should be classified as skin sensitizer (Category 1B) and labeled as H317: May cause an allergic skin reaction.