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

Endpoint summary

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:

From 30 April to 05 June 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study run to a method comparable with current guidelines and to GLP

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

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Oxon, UK
- Age at study initiation: eight to twelve weeks old
- Weight at study initiation: 15 to 23 g
- Housing: individually housed in suspended solid floor polypropylene cages furnished with softwood woodflakes
- Diet (e.g. ad libitum): Free access to food (2014C Teklad Global Rodent diet supplied by Harlan Laboratories UK Ltd., Oxon, UK)
- Water (e.g. ad libitum): Free access to mains tap water
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25°C
- Humidity (%): 30 to 70%
- Air changes (per hr): approximately fifteen changes per hour
- Photoperiod (hrs dark / hrs light): twelve hours continuous light (06.00 to 18.00) / twelve hrs dark

IN-LIFE DATES: From: To:

Vehicle:

other: ethanol/distilled water 7:3

Concentration:

25%, 10% or 5% w/w in ethanol/distilled water 7:3

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Compound solubility:
- Irritation: No signs of systemic toxicity, visible local skin irritation or irritation indicated by an equal to or greater than 25% increase in mean ear thickness were noted.
- Lymph node proliferation response:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay in the Mouse
- Criteria used to consider a positive response: The test item will be regarded as a sensitizer if at least one concentration of the test item results in a threefold or greater increase in 3HTdR incorporation compared to control values.

TREATMENT PREPARATION AND ADMINISTRATION: Groups of five mice were treated with the test item at concentrations of 25%, 10% or 5% w/w in ethanol/distilled water 7:3. The preliminary screening test suggested that the test item would not produce systemic toxicity or excessive local skin irritation at the highest suitable concentration. The mice were treated by daily application of 25 μL of the appropriate concentration of the test item to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The test item formulation was administered using an automatic micropipette and spread over the dorsal surface of the ear using the tip of the pipette. A further group of five mice received the vehicle alone in the same manner. The positive control animals were similarly treated to the test animals except that 25 μL of the positive control item, α-Hexylcinnamaldehyde, tech., 85%, at a concentration of 15% v/v in ethanol/distilled water 7:3 was applied to the dorsal surface of each ear.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

Data was processed to give group mean values for disintegrations per minute and standard deviations where appropriate. Individual and group mean disintegrations per minute values were assessed for dose response relationships by analysis of homogeneity of variance followed by one way analysis of variance (ANOVA). In the event of a significant result from the ANOVA, pairwise comparisons were performed between control and treated groups. For homogenous datasets Dunnett’s Multiple Comparison test was used and for non-homogenous datasets Dunnett’s T3 Multiple Comparison Method was used.
Probability values (p) are presented as follows:
P<0.001 ***
P<0.01 **
P<0.05 *
P≥0.05 (not significant)

Positive control results:

α-Hexylcinnamaldehyde, tech., 85% gave a Stimulation Index of greater than 3 when tested at a concentration of 15% v/v in ethanol/distilled water 7:3.

Parameter:

SI

Remarks on result:

other: Vehicle control group: na 5% w/w in ethanol/distilled water 7:3: 1.19 10% w/w in ethanol/distilled water 7:3: 1.49 25% w/w in ethanol/distilled water 7:3: 1.99

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Mean dpm/Animal: Vehicle control group:379.01 5% w/w in ethanol/distilled water 7:3: 450.54 10% w/w in ethanol/distilled water 7:3: 565.94 25% w/w in ethanol/distilled water 7:3: 755.86

There were no deaths. No signs of systemic toxicity were noted in the test or control animals during the test.

Body weight change of the test animals between Day 1 and Day 6 was comparable to those observed in the corresponding control group animals over the same period.

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test item was considered to be a non- sensitizer under the conditions of the test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A LLNA study was conducted according to OECD 429 using mouse (Henzell G, 2013). Key study.

It was concluded that the test substance was considered to be a non-sensitizer under the conditions of the test.

Migrated from Short description of key information:
A LLNA study (Henzell G, 2013) is available which is key study. This study showed the test substance is not sensitising.

Justification for selection of skin sensitisation endpoint:
This study was conducted according to OECD 429 using mouse.

Justification for classification or non-classification

Skin sensitisation: Animal test give negative result (SI <3 (actual value 1.99)).

Therefore in accordance with Regulation (EC) No. 1272/2008 Table 3.4.2 the test substance is not classified as an sensitiser.