2,2,6,6-tetramethylpiperidinooxy

Endpoint summary

Description of key information

Based on the irritation parameters and the histopathological evaluation following 4-hour occlusive test item application in an in vivo skin irritation/corrosion study in male and female rabbits, 2,2,6,6-tetramethylpiperidinooxy was considered to be corrosive to the skin. In a supporting study according to a modified Draize protocol, the test item appeared to be slightly irritant to skin.

As a consequence of the instillation of 2,2,6,6-tetramethylpiperidinooxy into the rabbit eye, effects were noted on cornea, iris and conjunctiva in all animals. In half of the animals effects deteriorated after an initial improvement and became so severe that the animals needed to be sacrificed on day 7. Thus, the effects were not expected to reverse within the observation period of 21 days.

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:

20-May to 10-June 1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

Study was not conducted in compliance with GLP, but is well documented and sufficient to cover this endpoint (conduction close to OECD 404). 3 male and 3 females animals were used, observation period was 21 days.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

3 male and 3 female amimals were used and observation period was 21 days after removal of patches.

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Species/Strain: Rabbit (New Zealand albino)
- Source: R and B Enterprise, Hamilton OH
- Body weigth: 2.7 to 3.1 kg
- Housing: single housing in stainless steel cages
- Diet: Purina Lab Rabbit Chow HF #5325, 150 g daily
- Water: Water supplied from a reverse-osmosis purifier, ad libitum
- Acclimation period: 14 days befor the first test-substance application

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C
- Humidity (%): 40 %
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

Approximateyl 24 hours prior to study initiation, fur was clipped from an area of approximateyl 240 cm2 on the back of each rabbit. A 0.5 g quantity of the test article was applied uniformly to each test side and was covered with a 2.5 x 2.3 cm adhesive dressing.

Duration of treatment / exposure:

4 hours, afterwards application sites were rinsed with 0.9% saline

Observation period:

21 days

Number of animals:

3F / 3M

Details on study design:

Application sites were examined for signs of dermal irritiation and corrosivity 50-60 min, 24, 48, and 72 hours, and 7, 14, and 21 days following removal of the wrappings.

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2.67

Max. score:

4

Reversibility:

not fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2.67

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 72 h.

Irritation parameter:

edema score

Basis:

animal #4

Time point:

24/48/72 h

Score:

2.33

Max. score:

4

Reversibility:

not fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

edema score

Basis:

animal #5

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

edema score

Basis:

animal #6

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 72 h.

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 72 h.

Irritation parameter:

erythema score

Basis:

animal #4

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

erythema score

Basis:

animal #5

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

erythema score

Basis:

animal #6

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 72 h.

Irritant / corrosive response data:

Brown areas were seen within the test sites of all tested rabbits 30-60 minutes after removal of the wrappings and persisted through the 72-hour scoring interval. Eschar formation was apparent in five out of six rabbits at that time. Therefore, two rabbits exhibiting the strongest signs of dermal irritation (Nos 3 and 6) were sacrificed following the 72-hour scoring interval and most severely affected dermal sections were subjected to histopathological investigation and compared to untreated skin. As a result, severe necrosis of the epidermis and moderate necrosis of the dermis were observed in correlation with acute mild to moderate inflammation of the dermis. Deeper necrosis including adnexa was seen with foci distribution.
In the other four animals, eschar formation persisted through day 7 or day 14. Cracking and/or concavity of the test site was also seen during the study. New or repaired skin was evident within the test sites of three of the four remainign rabbits by day 21.

Interpretation of results:

Category 1C (corrosive) based on GHS criteria

Conclusions:

Based on the irritation parameters and the histopathological evaluation following 4-hour occlusive test item application in an in vivo irritation/corrosion study in male and female rabbits, 2,2,6,6-tetramethylpiperidinooxy is considered to be corrosive to the skin.
As a conclusion, the test substance is classified for this endpoint in accordance to the CLP Regulation (EC) No 1272/2008 as corrosive to the skin, category 1C.

Reference 2

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Remarks:

Observation period too short, reversibility of effects cannot be assessed. Poor documentation of results.

Principles of method if other than guideline:

modified Draize protocol (Draize et al.1944, J. Pharmacol. Exp. Ther. 821, 377–390; Zisu 1995, Contact Dermatitis 32, 74–77)

GLP compliance:

no

Species:

guinea pig

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Species/Strain: Guinea pig
- Source: Charles River Wiga, Sulzfeld, Germany
- Body weigth: 300 to 400 g
- Housing: single housing in stainless steel cages
- Diet: Food pellets ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C
- Humidity (%): 60 %
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

occlusive

Preparation of test site:

other: One flank was shaved, the other scarified on the day before administration.

Vehicle:

other: petrolatum

Controls:

yes, concurrent vehicle

yes, concurrent positive control

Amount / concentration applied:

0.5 mL / 10mM or 100 mM

Duration of treatment / exposure:

24 h

Observation period:

72 h

Number of animals:

6

Details on study design:

The test substance (0.5 ml:10 mM, or 100 mM final concentration) in petrolatum was applied by an occlusive patch for 24 h on the flank carefully shaved the day before. The substances were also applied on the contralateral scarified flank. Petrolatum was used as a negative control and an aqueous solution of 5% sodium lauryl sulfate (SLS) as a positive control in each animal. Animals were observed for erythema and oedema. The scores 24 and 72 h after application of the substances were added (non-scarified and scarified zones). The primary irritation values are calculated by averaging values for erythema from all sites (abraded and non-abraded), averaging the values for edema from all sites and adding the average values. The total was divided by 4 corresponding to the sum of two scores (erythema and oedema) obtained after 24 and 72 h. The mean is termed the primary cutaneous irritation index and may be used to classify the test substance (Zisu, 1995).

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 24 and 72h

Score:

1.7

Reversibility:

not specified

Remarks on result:

probability of mild irritation

Irritation parameter:

overall irritation score

Remarks:

positive control 5% SLS

Basis:

mean

Time point:

other: 24 and 72h

Score:

2.5

Reversibility:

not specified

Remarks on result:

probability of moderate irritation

Irritant / corrosive response data:

At a concentration of 100 mM, the test item was found to be slightly irritant (score 1.7), when compared with the moderate irritant 5% SLS (score 2.5). At a concentration of 10 mM no signs of skin irritation were observed.

Interpretation of results:

study cannot be used for classification

Conclusions:

As a result, this modified Draize test shows that the test item is slightly irritant to skin. However, there is too little information available for classification according to the CLP Regulation (EC) No 1272/2008.

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:

02 June to 24 June 1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

Study was not conducted in compliance with GLP, but is well documented and sufficient to cover this endpoint (conduction close to OECD 405).

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

yes

Remarks:

6 animals (3M / 3F) were used.

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Species/Strain: Rabbit (New Zealand albino)
- Source: R and B Enterprise, Hamilton OH
- Body weigth: 2.9 to 3.2 kg
- Housing: single housing in stainless steel cages
- Diet: Purina Lab Rabbit Chow HF #5325, 150 g daily
- Water: Water supplied from a reverse-osmosis purifier, ad libitum
- Acclimation period: 14 days befor the first test-substance application

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C
- Humidity (%): 40 %
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

0.1 g undiluted test item

Duration of treatment / exposure:

Test substance was not removed.

Observation period (in vivo):

21 days

Number of animals or in vitro replicates:

3M / 3F

Details on study design:

Undiluted test substance (0.1 g) was placed in the conjunctival sac of one eye, the other served as control. Test substance was not removed. Evaluation of results 1, 2, 3, 4, 7, 14 and 21 days after instillation of the test substance.

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Remarks on result:

positive indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

cornea opacity score

Basis:

animal #4

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Remarks on result:

positive indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #5

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

positive indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #6

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.33

Max. score:

2

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

iris score

Basis:

animal #4

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 7 days

Remarks on result:

positive indication of irritation

Irritation parameter:

iris score

Basis:

animal #5

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 7 days

Remarks on result:

positive indication of irritation

Irritation parameter:

iris score

Basis:

animal #6

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2.33

Max. score:

3

Reversibility:

fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

3

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

conjunctivae score

Basis:

animal #4

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #5

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

not fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #6

Time point:

24/48/72 h

Score:

2.67

Max. score:

3

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2.67

Max. score:

4

Reversibility:

fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritation parameter:

chemosis score

Basis:

animal #4

Time point:

24/48/72 h

Score:

3.33

Max. score:

4

Reversibility:

fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #5

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 21 days

Remarks on result:

positive indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #6

Time point:

24/48/72 h

Score:

3.33

Max. score:

4

Reversibility:

not reversible

Remarks on result:

positive indication of irritation

Remarks:

Animal was sacrificed after 7 days.

Irritant / corrosive response data:

In treated eyes an inceased density of opacity was noted, in 3 out of 6 animals the finding was reversible, however, in the other 3 animals density was increasing again starting day 4 or 7. For the iris, the conjunctiva and chemosis scores, a comparable trend was observed. Due to the severity of those findings, the 3 rabbits with the deteriorating process were euthanized after the 7-day examination.

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

As a consequence of the instillation of 2,2,6,6-tetramethylpiperidinooxy into the rabbit eye, effects were noted on cornea, iris and conjunctiva in all animals. In half of the animals effects deteriorated after an initial improvement and became so severe that the animals needed to be sacrificed on day 7. Thus, the effects were not expected to reverse within the observation period of 21 days.
As a conclusion, the test substance is classified for this endpoint in accordance to the CLP Regulation (EC) No 1272/2008 in Category 1 (Irreversible Effects on the Eye).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

In an in vivo skin irritation/corrosion study in male and female rabbits, 2,2,6,6-tetramethylpiperidinooxy was found to be corrosive to the skin. A supporting study according to a modified Draize protocol revealed the test item to be slightly irritant to skin. Further evidence for the corrosive effects to the skin resulted from an acute dermal toxicity study; the mean lethal dose (LD50) of the test substance was found to be lower than 2000 mg/kg bw in male and female rabbits in a limit test. Severe corrosive effects have been estimated to be the cause for mortality. As a conclusion, the test substance is classified for this endpoint in accordance to the CLP Regulation (EC) No 1272/2008 as corrosive to the skin, category 1C.

 

In an in vivo eye irritation study in rabbits, severe effects were noted on cornea, iris and conjunctiva in all animals that were considered not to be reversible. As a conclusion, the test substance is classified for this endpoint in accordance to the CLP Regulation (EC) No 1272/2008 in Category 1 (Irreversible Effects on the Eye).