1,3-bis(1-isocyanato-1-methylethyl)benzene

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Aug. 27, 1981 to Oct. 27, 1981

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Principles of method if other than guideline:

Method: Study performed according to method described in Federal Register, Volume 43, 37336, Part 163.81-5 and Federal
Register, Volume 44, 44054, Part 772.112-25 which is equilvalent or similar to OECD Guideline 404.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1,3-bis(1-isocyanato-1-methylethyl)benzene

EC Number:

220-474-4

EC Name:

1,3-bis(1-isocyanato-1-methylethyl)benzene

Cas Number:

2778-42-9

Molecular formula:

C14H16N2O2

IUPAC Name:

1,3-bis(1-isocyanato-1-methylethyl)benzene

Details on test material:

- Name of test material (as cited in study report): 11583B15
- Physical state: Clear, colorless liquid
- Analytical purity: 91.58 %
- Density at 25 °C: 1.06749 g/cm3 (equivalent to 1067.49 mg/mL)
- Stability under test conditions: Stable at room temperature or below and slowly reacts with water
- Storage condition of test material: Refrigerator

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: MKS Research Inc., 428 Cedar Grove Lane, Somerset, New Jersey 08873
- Weight at study initiation: 2.9-3.8 kg
- Age at study initiation: Adult
- Housing: Individually housed in stainless steel cages with wire mesh walls and floors and automatic watering devices
- Diet (e.g. ad libitum): Purina Rabbit Chow, ad libitum
- Water (e.g. ad libitum): Filtered tap water, ad libitum
- Acclimation period: 7 d

ENVIRONMENTAL CONDITIONS
- Air changes (per hr): 14/h
- Photoperiod (hrs dark / hrs light): 12 h dark/12 h light cycle

Test system

Type of coverage:

occlusive

Preparation of test site:

abraded

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.5 mL
- Concentration (if solution): Undiluted

Duration of treatment / exposure:

24 h

Observation period:

14 d

Number of animals:

Six male

Details on study design:

TEST SITE
- Area of exposure: 1 inch square
- Type of wrap if used: Patches were held in place with Blenderm tape and covered with an occlusive binder consisting of plastic wrap, gauze wrap, adhesive tape and masking tape


REMOVAL OF TEST SUBSTANCE
- Washing (if done): Test sites were wiped (but not washed)
- Time after start of exposure: 24 h


SCORING SYSTEM: Draize scoring system

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 72 h

Score:

3.3

Max. score:

8

Reversibility:

not reversible

Results 2

Irritation parameter:

erythema score

Remarks:

With intact skin

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

24 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Results 3

Irritation parameter:

erythema score

Remarks:

With abraded skin

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

24 h

Score:

2.17

Max. score:

4

Reversibility:

not reversible

Results 4

Irritation parameter:

edema score

Remarks:

With intact skin

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

24 h

Score:

1

Max. score:

4

Reversibility:

not reversible

Results 5

Irritation parameter:

edema score

Remarks:

With abraded skin

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

24 h

Score:

1.42

Max. score:

4

Reversibility:

not reversible

Results 6

Irritation parameter:

erythema score

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

48 h

Remarks on result:

other: Data not available

Results 7

Irritation parameter:

edema score

Basis:

mean

Remarks:

Mean of the left and right side of 6 animals

Time point:

48 h

Remarks on result:

other: Data not available

Results 8

Irritation parameter:

erythema score

Remarks:

With intact skin

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

72 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Results 9

Irritation parameter:

erythema score

Remarks:

With abraded skin

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

72 h

Score:

2.25

Max. score:

4

Reversibility:

not reversible

Results 10

Irritation parameter:

edema score

Remarks:

With intact skin

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

72 h

Score:

1

Max. score:

4

Reversibility:

not reversible

Results 11

Irritation parameter:

edema score

Remarks:

With abraded skin

Basis:

mean

Remarks:

Mean of left and right side of 6 animals

Time point:

72 h

Score:

1.42

Max. score:

4

Reversibility:

not reversible

Irritant / corrosive response data:

Mean scores at 24 h:
- Erythema score at intact sites: 2.0
- Edema score at intact sites: 1.0
- Erythema score at abraded sites: 2.17
- Edema score at abraded sites: 1.42

Mean scores at 72 h:
- Erythema score at intact sites: 2.0
- Edema score at intact sites: 1.0
- Erythema score at abraded sites: 2.25
- Edema score at abraded sites: 1.42

- Scores for erythema ranged from very slight to severe for intact sites and from well-defined to severe for abraded sites
- Scores for edema ranged from none to slight for both intact and abraded sites
- All animals exhibited irritation at 72 hours
- By day 6, all sites showed eschar formation which persisted at all but 2 sites until termination at Day 13.

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant)

Conclusions:

Under the test conditions, the test material was considered to be moderately irritating to skin in rabbit.

Executive summary:

A study was conducted to evaluate the skin irritation of the test substance. The study was performed according to a method equivalent or similar to OECD Guideline 404, in compliance with GLP. The substance (0.5 mL) was applied to the intact and abraded skin of rabbits via a 24 h occlusive patch. Scoring was done at 24 and 72 h and continued until Day 13 post-dose. At the 24 and 72 h intervals, scores for erythema ranged from very slight to severe for intact sites and from well-defined to severe for abraded sites. Scores for edema ranged from none to slight for both intact and abraded sites. There were no important differences in skin irritation between intact and abraded sites. All animals exhibited irritation at 72 h. By Day 6, all sites showed eschar formation which persisted at all but 2 sites until termination. Under the test conditions, the primary irritation index was calculated to be 3.3 and therefore the test substance was considered to be moderately irritating to skin in rabbit (Knickerbocker, 1981).