Registration Dossier

The potential of maleic anhydride to induce skin corrosion/irritation and eye irritation was tested in suitable in vivo test methods. Based on the results, the maleic anhydride must be considered corrosive to the skin and damaging to the eyes.

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Principles of method if other than guideline:

New Zealand White rabbits were used to determine the skin irritation potential of maleic anhydride. Test substance (0.5 g) was applied to two intact skin locations on the backs of six rabbits for four hours.

GLP compliance:

no

Specific details on test material used for the study:

The maleic anhydride used in this study was supplied by the Chevron Chemical Company, Petrochemical Division, Industrial Chemicals, San Francisco, California. It was a white solid which was ground to a fine powder with a mortar and pestle.

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Sex: male New Zealand White rabbits
- Housing: individually housed in wire-bottom cages
- Diet: daily ration of a commercial laboratory feed (approximately 4 oz)
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

not specified

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.5 g

Duration of treatment / exposure:

4 hours

Observation period:

Irritation was scored at 4, 24, 48, 72 hours and after 7 days.

Number of animals:

6

Details on study design:

TEST SITE
- Area of exposure: the test material powder was applied to each of two separate intact sites on each rabbit.
- Type of wrap if used: After application of the material the sites were covered with a gauze patch which was secured by adhesive tape. The trunk of each animal was loosely wrapped in a plastic sheet. Paper' towels were wrapped around the plastic sheet to prevent tearing. A collar was placed on each animal to protect the wrappings during the exposure period.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: 4 hours

OBSERVATION TIME POINTS
- 4, 24, 48, 72 hours and at 7 days

SCORING SYSTEM:
- Method of calculation: Draize scoring system (please refer to box " Any other information on materials and methods incl. tables")

Irritation parameter:

erythema score

Basis:

animal #1

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #1

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #2

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #2

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #3

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #3

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

3.3

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #4

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #4

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #5

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #6

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #6

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #1

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

3.3

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #1

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

3.3

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #3

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #3

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #4

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #4

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #5

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

3.66

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #5

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

3.66

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #6

Remarks:

(site 1)

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #6

Remarks:

(site 2)

Time point:

24/48/72 h

Score:

3.33

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritant / corrosive response data:

Severe skin irritation was present in both treated areas of all rabbits for the entire 7-day observation period. For detailed results please refer to table 1 in box " Any other information on results incl. tables".

Other effects:

The pathological findings exhibit that eschar formation with epidermal regeneration was present in all of the sections. One section (not further specified) had an area of granulation tissue down to the muscle with some regeneration of epidermal tissue over the area.

Table 1: The skin corrrosion potential of maleic anhydride

Exposition:	4 h occlusive
		Site 1		Site 2
Animal	Reading	Erythema	Edema	Erythema	Edema
1	4 h	4	3	4	3
2	4 h	4	4	4	4
3	4 h	4	4	4	2
4	4 h	4	4	4	4
5	4 h	2	1	2	4
6	4 h	4	2	4	2
1	24 h	4	4	4	4
2	24 h	4	4	4	4
3	24 h	4	4	2	2
4	24 h	4	4	4	4
5	24 h	4	4	4	4
6	24 h	4	4	4	4
1	48 h	4	3	4	3
2	48 h	4	4	4	4
3	48 h	4	4	4	2
4	48 h	4	4	4	4
5	48 h	4	4	4	4
6	48 h	4	4	4	4
1	72 h	4	3	4	3
2	72 h	4	4	4	4
3	72 h	4	4	4	2
4	72 h	4	4	4	4
5	72 h	4	3	4	3
6	72 h	4	4	4	2
1	7 d	4	2	4	2
2	7 d	4	4	4	4
3	7 d	4	4	4	2
4	7 d	4	4	4	4
5	7 d	4	2	4	2
6	7 d	4	4	4	4

At 24 hours, the mean Draize scores for erythema and edema for site 1 (site 2) were 4.0 (3.7) and 4.0 (3.7), respectively. At 48 hours, the mean scores for erythema and edema were 4.0 (4.0) and 3.8 (3.5), respectively. At 72 hours, the mean erythema and edema scores were 4.0 (4.0) and 3.7 (3.0), respectively. At 7 days, the mean erythema and edema scores were 4.0 (4.0) and 3.3 (3.0), respectively.

Interpretation of results:

Category 1B (corrosive) based on GHS criteria

Conclusions:

In this study under the given conditions the test item showed corrosive effects. The test item is therefore classified as corrosive and in accordance with annex 6 of CLP regulation 1272/2008 classification as Skin Corr. 1B, H314 is warranted.

Executive summary:

In a primary dermal irritation study 6 male New Zealand white rabbits were dermally exposed to 0.5 mg of the test item maleic anhydride for 4 hours to two intact skin locations on the back under occlusive conditions. Irritation was scored at 4, 24, 48, and 72 hours and at 7 days after in accordance to Draize. Severe skin irritation was present in both treated areas of most rabbits for the entire 7-day observation period. Eschar formation with epidermal regeneration was present in all of the sections. One section (not further specified) had an area of granulation tissue down to the muscle with some regeneration of epidermal tissue over the area.

Based on the results, the test item is considered as corrosive and in accordance with ATP13 to CLP regulation 1272/2008 classification as Skin Corr. 1B, H314 is warranted.

Endpoint conclusion:

adverse effect observed (corrosive)

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-06-17 to 1991-08-01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

GLP compliance:

yes

Specific details on test material used for the study:

Maleic anhydride was received June 11, 1991. The test article was a white, crystalline solid and was stored at room temperature.

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: the test article was administered undiluted. Individual doses of the test article were weighed onto aluminum foil to facllltate dosing

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Johnson Rabbit Ranch, Wilkinson, IN
- Age at study initiation: 2-3 months
- Weight at study initiation: 1.84 to 2.81 kg
- Housing: individually in stainless steel cages measuring 61.0 x 45.5 x 41.0 cm
- Diet: 150 g of Purina Lab Rabbit Chow HF #5326 per rabbit per day
- Water: reverse osmosis-purified water, ad libitum
- Acclimation period: approximately 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23
- Humidity (%): 54
- Photoperiod (hrs dark / hrs light): 12 / 12

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.1 g of the undiluted test item

Duration of treatment / exposure:

0.1 g of the undiluted test article was placed in the everted lower lid of tte right eye of each rabbit. The lids of all treated eyes were held closed for approximately two seconds following test article administration. The other eye was left untreated.

Observation period (in vivo):

1, 24 and 48 hours following test article administration (according to the study protocol, treated eyes were to be examined a minimum of 72 hours after dosing. However, due to signs of severe ocular irritation, the study was terminated following the 48 hour examination.)

Duration of post- treatment incubation (in vitro):

n.a.

Number of animals or in vitro replicates:

three animals per sex

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no washing

SCORING SYSTEM: According to OECD testing guideline 405 (Draize).

TOOL USED TO ASSESS SCORE: fluorescein and ultraviolet light (after the 1 hr scoring)

OTHER:
- All rabbits were observed daily for mortalIty and morbidity.
- The rabbits were weighed immediately prior to dosing.

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24 h

Score:

3.8

Max. score:

4

Reversibility:

not reversible

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

48 h

Score:

3.8

Max. score:

4

Reversibility:

not reversible

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

72 h

Remarks on result:

not measured/tested

Remarks:

The study was terminated at day 2 due to severe effects/corrosion.

Irritation parameter:

iris score

Basis:

mean

Time point:

24 h

Score:

2

Max. score:

2

Reversibility:

not reversible

Irritation parameter:

iris score

Basis:

mean

Time point:

48 h

Score:

2

Max. score:

2

Reversibility:

not reversible

Irritation parameter:

iris score

Basis:

mean

Time point:

72 h

Remarks on result:

not measured/tested

Remarks:

The study was terminated at day 2 due to severe effects/corrosion.

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24 h

Score:

2

Max. score:

3

Reversibility:

not reversible

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

48 h

Score:

3

Max. score:

3

Reversibility:

not reversible

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

72 h

Remarks on result:

not measured/tested

Remarks:

The study was terminated at day 2 due to severe effects/corrosion.

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Irritation parameter:

chemosis score

Basis:

mean

Time point:

48 h

Score:

4

Max. score:

4

Reversibility:

not reversible

Irritation parameter:

chemosis score

Basis:

mean

Time point:

72 h

Remarks on result:

not measured/tested

Remarks:

The study was terminated at day 2 due to severe effects/corrosion.

Irritant / corrosive response data:

The maximum eye irritation score was 106.7 (out of 110) 48 hours after administration of the test item. For detailed results please refer to Table 1 in box "Any other information on results incl. tables".

Other effects:

No deaths occurred during the study.However, two rabbits were vocal immediately following test article administration and signs of ocular irritation were severe. Therefore, out of concern for the animals' pain and discomfort, the study was terminated following the 48-hour examination.
One animal also developed corneal bulging, an ocular lesion not addressed by the Draize and OECD criteria.

Table 1: Summary of eye irritation score

		Cornea		Iris	Conjunctiva			Sex
Animal	Reading	Opacity	Area involved	Iris	Redness	Chemosis	Discharge	Sex
1	1 hrs	4	4	2	2	3	3	M
2	1 hrs	4	4	2	2	3	2	M
3	1 hrs	4	4	2	2	4	3	M
4	1 hrs	4	4	2	2	4	2	F
5	1 hrs	4	4	2	2	3	3	F
6	1 hrs	4	4	2	2	4	3	F
1	24 hrs	4	4	2	2	4	3	M
2	24 hrs	4	4	2	2	4	3	M
3	24 hrs	4	4	2	2	4	3	M
4	24 hrs	4	4	2	2	4	3	F
5	24 hrs	3	4	2	2	4	3	F
6	24 hrs	4	4	2	2	4	3	F
1	48 hrs	4	4	2	3	4	3	M
2	48 hrs	4	4	2	3	4	3	M
3	48 hrs	4	4	2	3	4	3	M
4	48 hrs	4	4	2	3	4	3	F
5	48 hrs	3	4	2	3	4	3	F
6	48 hrs	4	4	2	3	4	3	F

Table 2: Total eye irritation score

Total irritation score (according to Draize)
Animal	Reading	Score
1	1 hr	106
2	1 hr	104
3	1 hr	108
4	1 hr	106
5	1 hr	106
6	1 hr	108
1	24 hrs	103
2	24 hrs	108
3	24 hrs	108
4	24 hrs	108
5	24 hrs	88
6	24 hrs	108
1	48 hrs	110
2	48 hrs	110
3	48 hrs	110
4	48 hrs	110
5	48 hrs	90
6	48 hrs	110
mean	1 hr	106.3
mean	24 hrs	104.7
mean	48 hrs	106.7

Interpretation of results:

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

Conclusions:

In this study under the given conditions the test item showed severe effects on rabbit eyes

Executive summary:

In a primary eye irritation study, maleic anhydride was administered undiluted at a dose of 0.1 g to the right eye of each of six New Zealand albino rabbits, with the left eye serving as an untreated control. The treated eye of each rabbit was scored for irritation at 1, 24- and 48-hours following test article administration. The control eye was used for comparison. According to the study protocol, treated eyes were to be examined a minimum of 72 hours after dosing. However, due to signs of severe ocular irritation, the study was terminated following the 48-hour examination. Irritation was scored according to OECD guideline 405 and to the criteria of Draize.

No deaths occurred during the study. However, two rabbits were vocal immediately following test article administration and signs of ocular irritation were severe. Therefore, out of concern for the animals' pain and discomfort, the study was terminated following the 48-hour examination. The maximum eye irritation score was 106.7 (out of a maximum of 110). The mean conjunctival erythema scores at 24 and 48 hours were 2.0 and 3.0, respectively. The mean conjunctival chemosis scores at 24 and 48 hours were 4.0 and 4.0, respectively. The corneal opacity scores at 24 and 48 hours were 3.8 and 3.8, respectively. The iridial lesions scores at 24 and 48 hours were 2.0 and 2.0, respectively.

In this study, maleic anhydride showed severe effects on rabbit eyes. Thus, based on the severity of the effects, the test item must be considered as eye damaging. In accordance with ATP13 to CLP Regulation 1272/2008 classification as Eye Dam. 1, H318 is warranted.

Endpoint conclusion:

adverse effect observed (irreversible damage)

Endpoint conclusion:

no study available

In a primary dermal irritation study (equivalent to OECD 404) 6 male New Zealand white rabbits were dermally exposed to 0.5 mg of the test item maleic anhydride for 4 hours to two intact skin locations on the back under occlusive conditions. Irritation was scored at 4, 24, 48, and 72 hours and at 7 days after in accordance to Draize. Severe skin irritation was present in both treated areas of most rabbits for the entire 7-day observation period. Eschar formation with epidermal regeneration was present in all of the sections. One section (not further specified) had an area of granulation tissue down to the muscle with some regeneration of epidermal tissue over the area.

Based on the results, the test item is considered as corrosive and in accordance with ATP13 to CLP regulation 1272/2008 classification as Skin Corr. 1B, H314 is warranted.

Supporting evidence for the corrosive potential of maleic anhydride is based on the results from a further in vivo study. In this study, two animals per concentration were treated with 50, 20, 10, 1, 0.5 and 0.1% maleic anhydride in oil for 20 hours. The treatment with 50% and 20% test substance, resulted in necrosis with a crust formation and subsequent scar formation. The leather-like necrosis together with the formation of deep crusts after 50% test substance treatment were evaluated as full thickness necrosis. This necrosis was followed by scar formation and poor healing. However, based on the prolonged treatment period of 20 hours instead of 4 hours, the study cannot be used for classification and thus the results are considered as supporting information.

In a primary eye irritation study (equivalent to OECD 405), maleic anhydride was administered undiluted at a dose of 0.1 g to the right eye of each of six New Zealand albino rabbits, with the left eye serving as an untreated control. The treated eye of each rabbit was scored for irritation at 1, 24- and 48-hours following test article administration. The control eye was used for comparison. According to the study protocol, treated eyes were to be examined a minimum of 72 hours after dosing. However, due to signs of severe ocular irritation, the study was terminated following the 48-hour examination.Irritation was scored according to OECD guideline 405 and to the criteria of Draize.

No deaths occurred during the study. However, two rabbits were vocal immediately following test article administration and signs of ocular irritation were severe. Therefore, out of concern for the animals' pain and discomfort, the study was terminated following the 48-hour examination. The maximum eye irritation score was 106.7 (out of a maximum of 110). The mean conjunctival erythema scores at 24 and 48 hours were 2.0 and 3.0, respectively. The mean conjunctival chemosis scores at 24 and 48 hours were 4.0 and 4.0, respectively. The corneal opacity scores at 24 and 48 hours were 3.8 and 3.8, respectively. The iridial lesions scores at 24 and 48 hours were 2.0 and 2.0, respectively.

In this study, maleic anhydride showed severe effects on rabbit eyes. Thus, based on the severity of the effects, the test item must be considered as eye damaging. In accordance with ATP13 to CLP Regulation 1272/2008 classification as Eye Dam. 1, H318 is warranted.

In accordance with ATP13 to CLP Regulation 1272/2008 classification as Eye Dam. 1, H318 and Skin Corr 1B, H314 is warranted.