Isobutyl methacrylate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Exposure period only 2 hours long. The study was performed in accordance with a recognized scientific procedure for analyzing the primary skin irritation of a test material in experimental animals. The study meets acceptable scientific standards and provides sufficient information to support the conclusion that the test material is a mildly irritating substance to the skin of rabbits.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1977

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Appraisal of the safety of chemicals  in foods, drugs and  cosmetics, FDA (Draize)(1959)

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Isobutyl methacrylate

EC Number:

202-613-0

EC Name:

Isobutyl methacrylate

Cas Number:

97-86-9

Molecular formula:

C8H14O2

IUPAC Name:

isobutyl methacrylate

Specific details on test material used for the study:

Isobutyl methacrylate; clear, colorless, undiluted liquid, supplied by Röhm GmbH & Co KG, Darmstadt.
Purity not specified but typically > 99 %

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: no data
- Age at study initiation:
- Weight at study initiation: 2.5 kg
- Housing: no data
- Diet (e.g. ad libitum): Kaninchenstansartdiät (Höing 222)
- Water (e.g. ad libitum): tap water
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 +/- 1
- Humidity (%): 50-60
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

occlusive

Preparation of test site:

other: shaved or shaved/scarified

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

undiluted

Duration of treatment / exposure:

2 hour(s)

Number of animals:

6

Details on study design:

Application: 2 hours, occlusive (shaved and shaved/scarified) Six New Zealand White rabbits were assigned 
to study. In order to investigate the  reproducibility of the effects, each rabbit had two separate dose sites
 (shaved and shaved/scarified), which were treated with 0.5 ml of undiluted test material. In addition, two 
untreated areas (shaved and  shaved/scarified) were used as the control. Only reactions which were  
different from those of the control were evaluated as positive reactions.  For each treated dose site, 0.5 ml 
of undiluted test material was soaked  onto a gauze patch (approx. 6 cm²) which was held in place with 
adhesive  tape on the shaved and shaved/scarified skin of the test animals. The  animals were fixed in a 
holding device and their bodies were wrapped in a  rubberised cloth for 2 hours. After this time, the 
dressing and adhesive  tape were removed and the local reactions were examined. Twenty-four and  
72 hours after application, the examinations were repeated. The test  result is the average of the scores 
of the 24- and 72-hour examination.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal: #2, #4, #6

Time point:

other: mean 24+72 h

Score:

0.5

Max. score:

4

Reversibility:

not fully reversible within: 72 h

Remarks on result:

other: occlusive, exposure time 2h, observation time 72 h, intact skin, reevaluated acc. CLP criteria

Results 2

Irritation parameter:

erythema score

Basis:

animal: #3, #5

Time point:

other: mean 24+72 h

Score:

1.5

Max. score:

4

Reversibility:

not fully reversible within: 72 h

Remarks on result:

other: occlusive, exposure time 2h, observation time 72 h, intact skin, reevaluated acc. CLP criteria

Results 3

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: mean 24+72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 72 h

Remarks on result:

other: occlusive, exposure time 2h, observation time 72 h, intact skin, reevaluated acc. CLP criteria

Results 4

Irritation parameter:

edema score

Basis:

animal: #2, #6

Time point:

other: mean 24+72 h

Score:

0

Max. score:

4

Remarks on result:

other: occlusive, exposure time 2h, observation time 72 h, intact skin, reevaluated acc. CLP criteria

Results 5

Irritation parameter:

edema score

Basis:

animal: #3, #4

Time point:

other: mean 24+72 h

Score:

0.5

Max. score:

4

Reversibility:

fully reversible within: 72 h

Remarks on result:

other: occlusive, exposure time 2h, observation time 72 h, intact skin, reevaluated acc. CLP criteria

Results 6

Irritation parameter:

edema score

Basis:

animal: #1, #5

Time point:

other: mean 24+72 h

Score:

1

Max. score:

4

Reversibility:

not fully reversible within: 72 h

Remarks on result:

other: occlusive, exposure time 2h, observation time 72 h, intact skin, reevaluated acc. CLP criteria

Results 7

Irritation parameter:

erythema score

Remarks:

mean

Basis:

animal: #1, #2, #3, #4, #5, #6

Time point:

other: mean 24+72 h

Score:

1.08

Max. score:

4

Reversibility:

not fully reversible within: 72 h

Remarks on result:

other: occlusive, exposure time 2h, observation time 72 h, intact skin, reevaluated acc. DSD (overall mean).

Results 8

Irritation parameter:

edema score

Basis:

animal: #1, #2, #3, #4, #5, #6

Time point:

other: mean 24+72 h

Score:

0.5

Max. score:

4

Reversibility:

not fully reversible within: 72 h

Remarks on result:

other: occlusive, exposure time 2h, observation time 72 h, intact skin, reevaluated acc. DSD (overall mean).

Any other information on results incl. tables

Evaluation acc. to Draize

Shaved skin: Under the described test conditions, 2 hours after application 5 of the animals showed signs 

of slight erythema, two of which progressed to moderate over the course of the test. Slight(1) to  moderate

(2) erythema persisted in 3 animals after 72 hours. Four animals  showed either slight(3) or moderate(1) 

erythema after 24 hours or 48  hours; slight to moderate edema persisted in 2 animals after 72  hours.

Mean primary irritation index (shaved skin): 0.79

Shaved/scarified skin: Under the described test conditions, 2 hours  and more pronounced at 24 hours 

after application, all six animals showed  slight to moderate erythema. 72 hours after application mostly 

slight  erythema was still present in all animals. All 6 animals showed mostly  slight edema after 2 and 

more pronounced after 24 hours. In 2 animals,  this effect persisted until 72 hours (1 slight, 1 moderate). Primary irritation index erythema (shaved/scarified): 1,42, primary irritation index edema (shaved/scarified)

: 0,75 Mean primary irritation index (shaved/abraded skin): 1.08

Overall index acc. to Draize: 1.87

Applicant's summary and conclusion

Interpretation of results:

slightly irritating

Remarks:

Migrated information only two hours exposure Criteria used for interpretation of results: not specified

Conclusions:

In this study the mean scores were below the criteria for classification acc. DSD and CLP regulation but the observation period was too short to
demonstrate the reversibility.

Executive summary:

In a study acc. to ‘Appraisal of the safety of chemicals in foods, drugs and cosmentics’ six New Zealand White rabbits were restained in stocks and the fur removed by clipping. Half of the exposed area was abraded and the other half remained intact. 0.5 ml (vol) of iso-butyl methacrylate was applied to shaved intact and abraded skin sites and covered with a patch. Two areas remained untreated as control. The animals were fixed and covered with a rubber cloth for only 2 hours instead of 4 hours. Then the patches were removed and the local reactions were evaluated after 24 and 72 hours in contrast to the control. Acc. to DSD criteria mean scores for shaved skin over 24 and 72 hours were 1.08 for erythema and 0.5 for edema. Acc. to CLP criteria all scores were < 2.3. the highest mean erythama score of the shaved skin was 2 in 1/6 animals, the highest edema score was 1 in 2/6 animals. In this study iso-butyl methacrylate is considered as slightly irritating to skin. The observation period in this study was too short to demonstrate the reversibility. As the exposure time was too short it cannot be excluded that the substance has a higher irritating potential. In another study conducted by the same study director and an exposure time of 24 h the irritating potential was slightly higher but the mean scores were also below the criteria for classification acc. DSD and CLP regulation but were also not fully reversible within the observation period of only 72 h.