2,4,6-triisopropyl-m-phenylene diisocyanate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1989-03-21 - 1989-05-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

Slight modifications from the guideline (e.g. precise description and scoring of corneal defects, additional examination of aqueous humour) do not affect the validity of the outcome of this study.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-triisopropyl-m-phenylene diisocyanate

EC Number:

218-485-4

EC Name:

2,4,6-triisopropyl-m-phenylene diisocyanate

Cas Number:

2162-73-4

Molecular formula:

C17H22N2O2

IUPAC Name:

2,4-diisocyanato-1,3,5-tris(propan-2-yl)benzene

Test material form:

liquid

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- healthy adult albino rabbits, females were nulliparous and not pregnant.
- Source: breeder Interfauna U.K. Ltd., Wyton, Huntingdon, England
- Age at study initiation: adult
- Weight at study initiation: 3.0 - 4.0 kg (weighed directly before application of the test compound)
- Housing: under standardised conventional conditions in individual stainless steel cages. Excrement trays beneath the cages contained low-dust wood shavings (type S 8/15, Ssniff Spezialdiäten GmbH, Soest). Shavings were regularly spot-checked for contaminants at the instance of the Department of Laboratory Animal Services.
All the animals in this study were kept in one room. For capacity reasons, rabbits treated with other test compounds were also housed in the same room. Adequate separation, clear cage and individual marks, and appropriate organisation of working procedures ensured that the test animals were not mixed up.
- Cleaning, disinfection; pest control: Room surfaces are cleaned at least once per month, and the room floor once per week, and disinfected with Zephirol®-10% (1% in water). Contamination of the diet and contact with the animals was always excluded. No pest control was performed in the animal rooms. The drinking apparatus were cleaned once a week.
- Diet (e.g. ad libitum): Standard diet "Ssniff K 4" (Ssniff Spezialdiäten GmbH, Soest), approx. 100 - 120 g per animal and day; feeding once per day in the morning.
- Water (e.g. ad libitum): Tap water was available ad libitum (between 7 and 19 hrs. by automatic watering apparatus)
- Acclimation period: at least 14 days in the quarantine station of the Department of Laboratory Animal Services before treatment and monitored for diseases (clinical). Shortly after arrival collective faeces specimens were examined for Coccidia oocysts.

Vaccination or treatment with antibiotics was performed neither prior to receipt of the animals nor during the acclimatization or study period.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3 °C
- Humidity (%): approx. 50 %
- Air changes (per hr): approx. 10 times per hour
- Photoperiod (hrs dark / hrs light): 12 hours, artificial illumination from 6 to 18 hrs CET
- Intensity of illumination: approx. 27 Watt/m2 floor area

RANDOMIZATION
The individual rabbits were randomly assigned to the respective treatment groups. Randomization was performed by means of a random number generator with varying starting conditions, using an Apple 2e.

For reasons of animal welfare, rabbits from former studies that tolerated treatment without signs are also used. In these animals the opposite skin area/eye which served as control in the preceding study is treated in the following study to prevent interactions of different test compounds.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Remarks:

clipping from the dorsal area of the trunk (6x6 cm)

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

500 µL

Duration of treatment / exposure:

4 hours

Observation period:

72 hours (If dermal irritation was observed, animals were monitored usually up to day 7 and 14 after patch removal until the changes had completely subsided, however for not more than 14 days after application.)

Number of animals:

6

Details on study design:

TEST SITE
- Area of exposure: approx. 6 cm²
- Type of wrap if used: semiocclusive dressing (Fixomull® - Stretch Klebevlies)

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

SCORING SYSTEM: erythema (redness), eschar formation and oedema formation

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Remarks:

I19

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 2

Irritation parameter:

edema score

Basis:

animal #1

Remarks:

I19

Time point:

24/48 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 3

Irritation parameter:

edema score

Basis:

animal #1

Remarks:

I19

Time point:

72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 4

Irritation parameter:

erythema score

Basis:

animal #2

Remarks:

I18

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Results 5

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

I18

Time point:

24 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 6

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

I18

Time point:

48 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 7

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

I18

Time point:

72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 8

Irritation parameter:

erythema score

Basis:

animal #3

Remarks:

I26

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 9

Irritation parameter:

edema score

Basis:

animal #3

Remarks:

I26

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 10

Irritation parameter:

erythema score

Basis:

animal #4

Remarks:

H17

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Results 11

Irritation parameter:

edema score

Basis:

animal #4

Remarks:

H17

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 12

Irritation parameter:

erythema score

Basis:

animal #5

Remarks:

H14

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Results 13

Irritation parameter:

edema score

Basis:

animal #5

Remarks:

H14

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 14

Irritation parameter:

erythema score

Basis:

animal #6

Remarks:

H23

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

Results 15

Irritation parameter:

edema score

Basis:

animal #6

Remarks:

H23

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

Irritant / corrosive response data:

edema score oedema formation: animal I19, I18 and I26 (7 days) score 2 max score 2 (fully reversible within 14 days)
edema score oedema formation: animal H17, H14 and H23 (7 days) score 0
Mean irritation indices:
erythema - 1.0
oedema - 0.1
The above results show that the test compound can be regarded as 'severely irritating to the skin'.

Other effects:

The skin was covered in spots by a whitish squamous layer in animals I19, I18, and H14 after 7 and 14 days, in animal I26 and H23 after 7 and 14 days respectively. The exposed area was hairless in all rabbits, excl. H23, after 14 days and indurated in all rabbits, excl. H14, after 7 days. Within the period of 24 hours to 14 days changes extended beyond the area of exposure in animals I19, I18, and I26 (not on day 14).

Any other information on results incl. tables

Table 1: Test for irritant effect on the skin (exposure duration: 4 hrs)

animal no.	body weight	DRAIZE grade after												Irritation index
		1 h		24 h		48 h		72 h		7 d		14 d
		e	o	e	o	e	o	e	o	e	o	e	o	e	o
I19	3.8 kg	1	0	2	1	2	1	2	0	2	2	0	0	2.0	0.7
I18	3.3 kg	1	0	2	0	2	1	2	1	1	2	2	0	2.0	0.7
I26	3.0 kg	2	0	2	0	2	0	2	0	1	2	0	0	2.0	0.0
H17	3.4 kg	1	0	0	0	0	0	0	0	0	1	3	0	0.0	0.0
H14	4.0 kg	1	0	0	0	0	0	0	0	0	1	0	0	0.0	0.0
H23	3.3 kg	1	0	0	0	0	0	0	0	2	1	0	0	0.0	0.0

e = erythema and eschar formation

o = oedema formation

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

The study was performed according to the OECD Guideline 404 with only negligible deviations and according to the good laboratory practice principles, it is considered to be of the highest quality (reliability Klimisch 1). The criteria of validity of the test system are fulfilled. The test material did induce irritation (moderate to severe inflammatory reactions that proved not to be reversible within 14 days) on the intact skin of rabbits. The diversity of signs may be related to the distinct sensitivity of animals. The test material was considered to be 'severely irritating to the skin' under the conditions of the test.

Executive summary:

The skin irritation potential of the test substance was investigated in New Zealand White rabbits according to OECD TG404 (Märtins, 1989). The test substance Triisopropylbenzoldiisocyanat (500 µl of the test substance) was applied semiocclusively to the intact skin for 4 hours; thereafter the skin reactions were monitored for 14 days. Interpretation of results was based on the nature, intensity, and reversibility of the responses observed and showed that the test compound can be regarded as 'severely irritating to the skin' (exposure period: 4 hours). The irritation indices were calculated in accordance with Guideline 83/467/EC No. 8 (EC Gazette, L 257).