Registration Dossier

Administrative data

Description of key information

There are two literature reports of skin sensitisation testing of2-piperazin-1-ylethylamine (aminoethyl piperazine) which do lack some details but are sufficient to come to a conclusion on the skin sensitising potential of 1-methyl piperazine. Reading across to this source substance is considered to be acceptable as they are suitably structurally similar.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Referenceopen allclose all

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:
Not applicable
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: 2e: Meets generally accepted scientific standards, well-documented and acceptable for assessment
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
yes
Remarks:
study examined sensitization capability of structurally similar amines
Principles of method if other than guideline:
Magnusson, B. and Kligman, A.M.: The identification of contact allergens by animal assay. The guinea pig maximization test. J. Invest. Dermatol. 52:268, 1969
GLP compliance:
not specified
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
At the time of registration adequate data for sensitisation where already available.
Species:
guinea pig
Strain:
not specified
Sex:
male/female
Details on test animals and environmental conditions:
Dunkin Hartley Haz:(DH)fBR albino guinea pigs (5-7 weeks old, 278-444 gr) were obtained from HRP Inc. (Denver, PA).
Route:
intradermal
Vehicle:
water
Concentration / amount:
5%
Day(s)/duration:
0
Adequacy of induction:
not specified
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
50%
Day(s)/duration:
on Day 14, 24 hour
Adequacy of challenge:
not specified
No. of animals per dose:
10/sex
Details on study design:
A range-finding study was conducted to select appropriate concentrations for the intradermal and epicutaneous procedures. Animals were inspected 24 and 48 hr after dosing for signs of necrosis and ulceration.

In the definitive sensitization test, groups of 10 male and 10 female guinea pigs each received 0.1 ml intradermal induction injections into 2 sites of the clipped shoulder skin as follows: 50% (v/v) Freund's complete adjuvant (FCA) water emulsion, the test material or vehicle, and the test material in FCA/water emulsion or FCA/water emulsion. Epicutaneous inductions were conducted 7 days later. The test material was applied to saturation ((0.2 ml) to a 2 x 4 cm filter paper, which was then placed on the test site and secured with tape. The patches were left in place for 48 hr, after which they were removed and the skin wiped free of any excess test material. Epicutaneous challenge was undertaken by applying 2 x 2 cm filter paper squares soaked in the appropriate concentration of the test material to a previously untreated site (right flank) 14 days after epicutaneous induction (i.e., 21 days from the start of the study). Patches were left in place for 24 hr, and the sites inspected for signs of irritation 24-48 hr after removal of the occlusive dressings.

Seven days after the challenge exposure(i.e., 28 days from the start of the study), the cross-challenge treatment was administered. Test materials were administered to the clipped skin in a similar manner as in the challenge phase but at previously untreated sites (left flank). Smaller patches (0.825 in2 adhesive bandages) were used in order to allow all of the test materials to fit on the test site. Materials were applied to saturation (0.03 ml per patch). Patches were left in place for 24 hr and the sites inspected for signs of irritation 24-48 hr after removal of the occlusive dressings.
Challenge controls:
Irritation control animals, five male and five female guinea pigs, received the same challenge procedures as in the definitive sensitization study, but did not have preceding intradermal and/or epicutaneous induction procedures. This allowed differentiation between primary skin irritation due to the test material, and those produced by a hypersensitivity reaction.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
5% intradermal, 50% epicutaneous induction, 25% challenge
No. with + reactions:
5
Total no. in group:
20
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0
No. with + reactions:
0
Total no. in group:
10
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
Not included
No. with + reactions:
0
Total no. in group:
0

Based on the probe study, the maximum concentrations used were 5% for the intradermal induction, 50% for epicutaneous induction and 25% for epicutaneous challenge phases. 

In the definitive study, five of 20 guinea pigs had a positive response. 

In the cross-reaction phase, animals induced with 50% demonstrated a greater response with diethylenetriamine (55%), hydroxyethylethylenediamine (75%), triethylenetetramine (45%) and piperazine (30%). Less of a response was observed in animals treated with ethylenediamine and tetraethylenepentamine (0 and 5% responded positive, respectively).

Interpretation of results:
sensitising
Remarks:
Migrated information
Conclusions:
Positive in guinea pig maximization test.

Positive results were also obtained in a cross challenge with several structurally similar alkyleneamines.
Executive summary:

The dermal sensitization potential was examined in the Guinea Pig Maximization Assay with aminoethylpiperazine (AEP). Cross-reactivity was also examined with structurally similar ethyleneamines. In this assay, AEP was positive and was shown to produce positive results when cross challenged with several structurally similar alkyleneamines.

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Study period:
Not applicable
Reliability:
2 (reliable with restrictions)
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study
Principles of method if other than guideline:
Magnusson, B. and Kligman, A.M.: The identification of contact allergens by animal assay. The guinea pig maximization test. J. Invest. Dermatol. 52:268, 1969
GLP compliance:
not specified
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
At the time of registration adequate data for sensitisation where already available.
Species:
guinea pig
Strain:
not specified
Sex:
not specified
Route:
intradermal
Vehicle:
water
Concentration / amount:
0.5%
Day(s)/duration:
0
Adequacy of induction:
not specified
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
0.5%
Day(s)/duration:
7, 48 hour
Adequacy of induction:
not specified
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
2%
Day(s)/duration:
21, 24hour
Adequacy of challenge:
not specified
No. of animals per dose:
15
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
No. with + reactions:
0
Total no. in group:
15
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
2%
No. with + reactions:
15
Total no. in group:
15
Remarks on result:
positive indication of skin sensitisation
Interpretation of results:
sensitising
Remarks:
Migrated information
Conclusions:
AEP was classified as a sensitiser.
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

We have no skin sensitization test for 1-methyl piperazine and due to the corrosive properties to the skin, it not considered ethical to perform a skin sensitization test in animals. It is therefore considered appropriate to use read across to Aminoethyl piperazine CAS No 140-31-8.

There are two skin sensitization studies available in the published literature a relatively modern study form 1997 and an older study from 1978, both studies are Klimisch 2.  Both studies show skin sensitization potential for aminoethyl piperazine , the study from 1997 is considered more reliable.

The main study for Aminoethyl piperazine is a Klimisch 2 rated study from the publish literature, K.S. Leung 1997: Sensitisation guinea pig RA using the OECD406 Magnusson and Kligman. In this study several alkyeneamines were tested for their skin sensitising potential following the OECD 406, Magnusson and Kligman guinea pig maximization assay. Aminoethyl piperazine was shown to be skin sensitizing, using 5% for the intradermal induction, 50% for the epicutaneous induction and 25% for the challenge doses, with a response seen in 5 out of 20 guinea pigs or 25%. There is another older Klimisch 2 rated supporting study on aminoethyl piperazine also from the published scientific literature, SS Thorgeirssen 1978: Sensitisation, guinea pig RA. In this publication the test substance was identified by its IUPAC name of 2-piperazin-1-ylethanamine, CAS No 140-31-8, again following the Magnusson and Kligman test protocol, but using lower concentration of 0.5% for induction and 2% for the challenge, a 100% response was reported. There is a limitation in this study that no information on the purity of the test sample was provided. There is no clear explanation for the apparent difference in the potency of aminoethyl piperazine between the two studies, it is possible that the sample in the older study may have contained contaminates that contributed to the sensitization as no information on the purity was provided.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

There is no standard validated animal test available to detect respiratory sensitisers.  All respiratory sensitisers of human significance are also skin sensitisers, however not all skin sensitisers are respiratory sensitisers.   There is no known evidence that aminoethyl piperazine is a respiratory sensitizer, therefore 1-methyl piperazine which has only a single reactive amine group is considered even less likely to have respiratory sensitizing potential.

Justification for classification or non-classification

We have no skin sensitization test for 1-methyl piperazine and due to the corrosive properties to the skin, it not considered ethical to perform a skin sensitization test in animals. It is therefore considered appropriate to use read across to Aminoethyl piperazine CAS No 140-31-8.

Based on the two available studies it is clear that aminoethyl piperazine is a skin sensitizer, the more modern and therefore more reliable study showed a 25% response, the EU CLP (GHS) guidelines require 30% or greater to less than 60% response for at the 5% intradermal induction dose used classification of 1B for skin sensitization . While the older 1978 study which used a 0.2% intradermal induction dose and showed 100% response would require a classification of category 1A. AS this study has no information to confirm the purity of the test substance and in view of 1-methyl piperazine being expected to be less reactive as it only has one amine group, the weight of evidence support a classification of Category 1B for skin sensitization based on the EU CLP (GHS) criteria.

There is no evidence that Aminoethyl piperazine is respiratory sensitisers and as the 1-methyl piperazine is expected to less reactive the aminoethyl piperazine due to the single amine group and therefore less likely to be sensitizing, it is concluded that 1-methyl piperazine is not classified as a respiratory sensitizer.