1-methylpiperazine

Endpoint summary

Description of key information

skin irritation/corrosion: corrosive

eye irritation: corrosive

1-methyl piperazine was test for skin and eye irritation in some old but scientifically valid studies. Corrosive effects were seen in both the eyes and in the skin after 5 minutes or longer exposure.  1-methyl  piperazine has not been tested for respiratory irritation, its effects on the skin and in the eyes would suggest that it is likely to be irritant to the respiratory tract if inhaled, but we have no specific information to confirm this. A corrositex study was done to confirm the transport packing group, this can also be translated into GHS classification for users.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14. Nov 1967 - 23. Nov 1967

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented report which meets basic scientific principles.

Qualifier:

no guideline available

Principles of method if other than guideline:

Method: BASF-Test.
Two animals were treated for 1, 5, 15 min using occlusive conditions. An application site of 2.5x2.5 cm was covered with the liquid test substance. After the application time (1, 5, 15 min) the skin was washed with Lutrol (conc.) and Lutrol/water (1:1). The animals were observed for 8 days and skin changes were recorded daily. The report describes findings after 24 hours and at the end of the observation period (8 days). For a final evaluation, the findings after 48 and 72 hours from the raw data were taken into account.

GLP compliance:

not specified

Species:

rabbit

Strain:

Vienna White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 3.43 and 3.93 kg

Type of coverage:

occlusive

Preparation of test site:

not specified

Vehicle:

unchanged (no vehicle)

Controls:

not specified

Duration of treatment / exposure:

1, 5 and 15 min and 20 h.

Observation period:

8 days

Number of animals:

2

Details on study design:

TEST SITE
- Area of exposure: 2.5x2.5 cm

REMOVAL OF TEST SUBSTANCE
- Washing (if done): with Lutrol (conc.) and Lutrol/water (1:1).
- Time after start of exposure: 1, 5 and 15 min post application

Irritation parameter:

erythema score

Remarks:

1 min exposure

Basis:

mean

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

edema score

Remarks:

I min exposure

Basis:

mean

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

> 4

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Remarks on result:

probability of severe irritation

Remarks:

Necrosis

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

> 4

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Remarks on result:

probability of severe irritation

Remarks:

Necrosis

Irritant / corrosive response data:

1 min exposure: heavy redness
5 min exposure: heavy redness and moderate necrosis.
15 min exposure: heavy redness and necrosis.
20 h exposure: heavy necrosis.

Mean erythema/necrosis score after 24, 48 and 72 h (animal1/2)

Exposure time	24 h	48 h	72 h
1 min	3/3	3/3	3/3
5 min	3/N+	N+/N+	N+/N+
15 min	N+/N++	N+/N++	N+/N++
20 h	N++/N++	N++/N++	N++/N++

The original BASF grading was converted into the numerical grading according the OECD Draize system.

N+: parchment-like necrosis.

N++: hart, leathery necrosis.

The application of the test substance caused necrosis to the exposed skin.

Interpretation of results:

study cannot be used for classification

Conclusions:

After 1 min exposure: heavy redness, after 5 min exposure: heavy redness and moderate necrosis, after 15 min exposure: heavy redness and necrosis, and after 20 h exposure: heavy necrosis.

Reference 2

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

other information

Study period:

The study was performed between 30 November 2011 and 01 December 2011.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 435 (In Vitro Membrane Barrier Test Method for Skin Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test system:

human skin model

Vehicle:

unchanged (no vehicle)

Details on test system:

The test item was assessed for its corrosivity potential using the CORROSITEX assay. The method was designed to be compatible with the following: OECD Guidelines for the Testing of Chemicals No. 435 “In VitroMembrane Barrier Test Method for Skin Corrosion” (adopted 19 July 2006)
The assay consisted of: a qualification screen with the Chemical Detection System a categorisation screen to identify test items as having either a high or low acid/alkaline reserve a definitive CORROSITEX assay
The test Material was applied neat.

TEST SITE
Approximately 500 µl of the test material was applied to the membrane disc.
The test material was applied topically to ensuring uniform covering.

Amount/concentration applied:

Amount(s) applied (volume or weight with unit): Approximately 500 µl of the test material was applied to the memebrane disc.
Concentration (if solution): The test material was used as supplied.

Duration of treatment / exposure:

4 hours or until breakthrough of the test item had occurred.

Irritation / corrosion parameter:

other: other: Breakthrough

Remarks on result:

other:

Remarks:

Basis: other: Time required for Test Item to Produce a Colour Change. Time point: 240 Minutes. Reversibility: other: Not applicable. Remarks: See mean breakthrough time below.

Other effects / acceptance of results:

Mean Breakthrough time of the four test item replicates: 48 minutes 41 seconds

RESULTS

Qualification Screen

The test item produced an immediate colour change therefore qualified for use in the CORROSITEX assay.

Categorisation Screen

The test item was assigned into Category 1.

Assay

	Test Item Breakthrough Time
	Vial 1	Vial 2	Vial 3	Vial 4
Start Time (hr:min:sec)	00:00:00	00:04:00	00:05:00	00:06:00
Detection Time (hr:min:sec)	00:50:30	00:52:00	00:52:10	00:55:04
Breakthrough Time (hr:min:sec)	00:50:30	00:48:00	00:47:10	00:49:04

Mean Breakthrough time of the four test item replicates:48 minutes 41 seconds

CORROSITEX CLASSIFICATION:                       CORROSIVE PACKING GROUP II 

 Positive/Negative Controls Quality Criteria

The results of the assay were accepted on condition of adherence to the positive and negative control item ranges given in the following table:

	Chemical	Concentration (weight %)	Breakthrough Time
Positive Control	Sulphuric Acid	95 – 98%	52 seconds
Negative Control	Citric Acid	10%	>60 minutes

hr=    hour(s)

min =  minute(s)

sec =  second(s)

Interpretation of results:

Category 1B (corrosive) based on GHS criteria

Conclusions:

The test item was considered to be CORROSIVE and can be assigned the UN Packing Group Criteria II.

Executive summary:

The test item was assessed for its corrosivity potential using the CORROSITEX assay. The method was designed to be compatible with OECD Guidelines for the Testing of Chemicals No. 435 “In VitroMembrane Barrier Test Method for Skin Corrosion” (adopted 19 July 2006).

The test item was considered to be CORROSIVE and can be assigned the UN Packing Group Criteria II.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08. Nov 1967 - 16. Nov 1967

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented report which meets basic scientific principles.

Principles of method if other than guideline:

Method: BASF-Test. 50 µL of the test substance were applied to the conjunctival sac of one eye in 2 animals. The animals were observed after 10 min, 1 and 24 h on the day of treatment and on day 3 and 8 afterwards. The eyes were not washed out after 24 hours as specified in OECD Guideline 405.

GLP compliance:

not specified

Species:

rabbit

Strain:

Vienna White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 2.63 and 2.68 kg

Vehicle:

unchanged (no vehicle)

Controls:

other: The adjacent eye served as saline control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 µl

Duration of treatment / exposure:

single application

Observation period (in vivo):

8 days

Number of animals or in vitro replicates:

2

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24 h

Score:

2

Max. score:

3

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

48 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

48 h

Score:

2

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

48 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: within 8 days

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

48 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 8 days

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

48 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

48 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

72 h

Remarks on result:

not measured/tested

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

72 h

Remarks on result:

not measured/tested

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

72 h

Remarks on result:

not measured/tested

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

72 h

Remarks on result:

not measured/tested

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Findings: animal1/animal2

Time	corneal opacity	erythema	chemosis
1 h	3/3	0/0	0/0
24 h	3/3	2/0	2/0
48 h	3/3	2/0	2/0
72 h	-/-	-/-	-/-
8 d	3/3	2/0	0/2

The original BASF grading was converted into the numerical grading according the OECD Draize system.

The 72 h reading is missing.

Mean values over 24 and 48 h (the 72 h reading is missing).

Animal1: Erythema: 2 ; Opacity: 3; Chemosis: 2;

Animal2: Erythema: 0 ; Opacity: 3; Chemosis: 0;

At the end of the observation period after 8 days the eyes were covered with purulence and crust formation was found in the periphery. In one animal after 5 days staphyloma formation was induced. The latter and opacity grade 3 are considered to be irreversible findings.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

skin irritation / corrosion:

There are two skin irritation studies available, one is an in vivo study in rabbits for skin irritation/corrosion.

This study is Klimisch 2 as it was pre-GLP and guidelines but is scientifically valid, with the test substance identified as monomethyl piperazine of 99% purity. Exposure for 5 minutes, 15 minutes and 20 hours all resulted in necrosis at the 24/48 and 72 hour observationsb. 1-methyl piperazine showed clear corrosive effects on the skin in rabbits after exposures from 5 minute and above, but only severe irritation after 1 minute exposure. In order to be able to classify 1-methyl piperazine for skin corrosion, exposure for up to 3 minutes and observation after 1 hour are required to indicate if classification as category 1A or 1B is required (BASF, 1968).

There is therefore a second study to clarify the classification, it was not considered ethical to perform an animal study instead an in vitro study was done (OECD 435, CORROSITEX). In this study 1-methyl piperazine showed average membrane breakthrough times of 48 minutes and 41 seconds. The study is Klimisch 1 carried out to GLP and according to the agreed protocol (Harlan, 2012a).

eye irritation:

There is an eye irritation study in rabbits available. This study is Klimisch 2 as it is an old study pre-GLP and pre guidelines, the study is however scientifically valid with sufficient details to be acceptable.  In this study severe effects were seen in the eyes of the rabbits with corneal opacity graded at 3 in all rabbits at the end of the eight day observation period. The severe effects were considered to be irreversible damage (BASF, 1968).

respiratory irritation:

We have no test data for respiratory irritation. Inhalation is not an expected route of exposure but based on its eye and skin corrosion 1-methyl piperazine would be expected to cause irritation to the respiratory tract if inhaled. However in the absence of any specific information it is not considered that a classification is required under EU CLP (GHS) for respiratory irritation.

Justification for classification or non-classification

1-methyl piperazine showed clear corrosive effects on the skin in rabbits after exposures from 5 minute and above, but only severe irritation after 1 minute exposure. In order to be able to classify 1-methyl piperazine for skin corrosion, exposure for up to 3 minutes and observation after 1 hour are required to indicate if classification as category 1A or 1B is required. In the absence of this information an in vitro Corrositex study was commissioned, this study showed an average membrane breakthrough time of 48 minutes and 41 seconds, using the criteria for this test >3 -60 minutes corresponds to the UN packing group II for skin corrosion. The UN pack packing groups I, II and III under GHS correspond to category 1A, 1B and 1C for skin corrosion.

Therefore 1-methyl piperazine is classified as Category 1B for skin corrosion by the EU CLP (GHS) criteria based on a combination of the in vivo and in vitro studies.

1-methyl piperazine produced irreversible damage to the cornea of rabbits and therefore it is classified as Category 1 for eye damage/irritation by the EU CLP (GHS) criteria.

In the absence of any specific data on irritation to the respiratory tract from inhalation of 1-methyl piperazine it is not proposed to classify for respiratory irritation.