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

Endpoint summary

Description of key information

1. Skin irritation (Märtins, 1989), GLP, OECD 404, rabbits, semiocclusive, 0.5 mL of undiluted test substance, 4 h exposure, irritating
2. Eye irritation (Märtins, 1989), GLP, OECD 405, rabbits, 0.1 mL of undiluted test substance, not irritating

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

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

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

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.

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

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

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

Irritation parameter:

edema score

Basis:

animal #1

Remarks:

I19

Time point:

72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

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

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

I18

Time point:

24 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 14 d

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

I18

Time point:

48 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 14 d

Irritation parameter:

edema score

Basis:

animal #2

Remarks:

I18

Time point:

72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 14 d

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

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

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

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

Irritation parameter:

erythema score

Basis:

animal #5

Remarks:

H14

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

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

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

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).

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

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).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

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:

1989-03-21 - 1989-05-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye 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

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues 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). In so doing contamination of the diet and contact with the animals is 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. Randomisation 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.

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

100 µl

Duration of treatment / exposure:

24 hours

Observation period (in vivo):

72 hours (If irritation was observed, animals were monitored for not more than 21 days after application)

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): with physiological NaCl solution
- Time after start of exposure: 24 hours

SCORING SYSTEM: cornea, fluorescein staining (epithelial defects), iris, aqueous flare, conjunctivae and discharge

TOOL USED TO ASSESS SCORE: hand-slit lamp

Irritation parameter:

cornea opacity score

Basis:

animal #1

Remarks:

H7

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

iris score

Basis:

animal #1

Remarks:

H7

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Irritation parameter:

conjunctivae score

Basis:

animal #1

Remarks:

H7

Time point:

24/48/72 h

Score:

0

Max. score:

3

Reversibility:

other: not applicable

Irritation parameter:

cornea opacity score

Basis:

animal #2

Remarks:

H25

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

iris score

Basis:

animal #2

Remarks:

H25

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Irritation parameter:

conjunctivae score

Basis:

animal #2

Remarks:

H25

Time point:

24/48/72 h

Score:

0

Max. score:

3

Reversibility:

other: not applicable

Irritation parameter:

cornea opacity score

Basis:

animal #3

Remarks:

H26

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

iris score

Basis:

animal #3

Remarks:

H26

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Irritation parameter:

conjunctivae score

Basis:

animal #3

Remarks:

H26

Time point:

24/48/72 h

Score:

0

Max. score:

3

Reversibility:

other: not applicable

Irritation parameter:

chemosis score

Basis:

animal #1

Remarks:

H7

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

chemosis score

Basis:

animal #2

Remarks:

H25

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

chemosis score

Basis:

animal #3

Remarks:

H26

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritant / corrosive response data:

No irritation of the eye was noted after the end of the observation period.

Other effects:

No other findings stated

Table 1: Test for irritant effect on the eye (expos . 24 hrs)

Animal no. (body weight)	tissue	signs	DRAIZE grades							Irritation index
			1 h	24 h	48 h	72 h	7 d	14 d	21 d
H7(3.4 kg)	cornea	o	0	0	0	0	0	-	-	0.0
		a	0	0	0	0	0	-	-
	fluorescein	i	-	0	-	-	-	-	-
		a	-	0	-	-	-	-	-
	iris / conjuncitvae / conjunctivae		0	0	0	0	0	-	-	0.0
		r	1	0	0	0	0	-	-	0.0
		s	0	0	0	0	0	-	-	0.0
	aqueous humour discharge		0	0	0	0	0	-	-
			1	0	0	0	0	-	-
H25 (3.1 kg)	cornea	o	0	0	0	0	0	-	-	0.0
		a	0	0	0	0	0	-	-
	fluorescein	i	-	0	-	-	-	-	-
		a	-	0	-	-	-	-	-
	iris / conjunctivae / conjunctivae		0	0	0	0	0	-	-	0.0
		r	1	0	0	0	0	-	-	0.0
		s	0	0	0	0	0	-	-	0.0
	aqueous humour discharge		0	0	0	0	0	-	-
			1	0	0	0	0	-	-
H26 (3.2 kg)	cornea	o	0	0	0	0	0	-	-	0.0
		a	0	0	0	0	0	-	-
	fluorescein	i	-	0	-	-	-	-	-
		a	-	0	-	-	-	-	-
	iris / conjunctivae / conjunctivae		0	0	0	0	0	-	-	0.0
		r	1	0	0	0	0	-	-	0.0
		s	0	0	0	0	0	-	-	0.0
	aqueous humour discharge		0	0	0	0	0	-	-
			1	1	1	1	0	-	-

o = opacity

a = area

i = intensity

r = redness

s = swelling

- = not examined

Interpretation of results:

GHS criteria not met

Conclusions:

The study was performed according to the OECD TG 405 with only minor 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 not induce any irritation or corrosion on rabbit eyes. The test material was considered to be not irritating under the conditions of the test (exposure duration 24 hours).

Executive summary:

Triisopropylbenzoldiisocyanat was investigated for its potential to cause irritation in the rabbit eye according to OECD TG 405 (Märtins, 1989). 100 µL of pure substance were instilled into the conjunctival sac, the untreated eye served as control. Interpretation of results was based on the nature, intensity, and reversibility of the responses observed. Under the conditions of this experiment the test compound was found to cause no irritation when applied to the rabbit eye mucosa. No corrosion effect was observed at each of the measuring intervals.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation:

2,4,6-triisopropyl-m-phenylene diisocyanate was investigated for its potential to induce irritation in rabbits (Märtins 1989, according to OECD 404). Onto the clipped skin of the dorsal area of the trunk 500 µL of the undiluted test compound were administered under semiocclusive conditions. After a 4 hour period, the patches were removed and the skin was carefully washed with water without altering the existing response, or the integrity of the epidermis. Observations were made after 24, 48 and 72 hours. If dermal irritation was observed, animals were monitored up to day 14 after patch removal. Dermal irritation was scored and recorded after termination of exposure. The degree of erythema/eschar formation and oedema formation was evaluated as specified by DRAIZE, and any serious lesions and toxic effects other than dermal irritation were also recorded. The mean irritation indices: were 1.0 for erythema and 0.1 for oedema. The results show that the test compound can be regarded as 'severely irritating to the skin'. Additionally the skin was covered in spots by a whitish squamous layer in 3 animals (I19, I18, and H14) after 7 and 14 days, in 2 animal (I26 and H23) after 7 and 14 days, respectively. The exposed area was hairless in all rabbits, but one (H23), after 14 days and indurated in all rabbits, but one (H14) after 7 days. Within the period of 24 hours to 14 days changes extended beyond the area of exposure in 3 animals (I19, I18, and I26 (not on day 14)). In conclusion, moderate to severe inflammatory reactions occurred following administration of the compound to the skin and the reactions proved not to be reversible within 14 days. The diversity of signs may be related to the distinct sensitivity of animals. Based on the results in the most sensitive animals the test compound can be regarded as 'severely irritating to the skin'.

 

Eye irritation:

The substance 2,4,6-triisopropyl-m-phenylene diisocyanate was investigated for its potential for eye irritation in rabbits in 1989 (Märtins, 1989; according to OECD 405). For the test 100 µL of undiluted substance were introduced into the conjunctival sac of one eye of three rabbits. After a period of 24 h the eye was carefully washed with physiological sodium chloride solution. The observations were made after 24, 48 and 72 hours after application. The signs of cornea (opacity and area affected), iris (hyperaemia, reaction to light), conjunctivae - i.e. conjunctiva of bulbus, lids, and nictitating membrane - (erythema, chemosis), and discharge were evaluated as described by DRAIZE, and the aqueous humour (opacity) was recorded as described by McDonald and Shadduck. In addition any serious lesions and toxic effects other than occular were also recorded. The examinations of cornea, iris and aqueous humour were facilitated by use of optical instruments (e.g. hand slit-lamp). To define epithelial damage, one drop of a 1% fluorescein solution was applied to the corneal surface 24 hours after application of the test compound. The results show that the test compound can be regarded as 'not irritating to the eye, as only slight iris / conjunctivae reactions and in cases aqueous humour discharge was seen in the animals 1 h after application of the test substance.

Justification for classification or non-classification

Skin irritation:

According to the Regulation (EC) No 1272/2008, the test material meets the criteria for classification and will require labelling as irritating to the skin. The test material is an irritant to the skin without full reversibility within 14 days and should be classified with Skin Irritant Cat. 2.

 

Eye irritation:

The mean grades of ocular reactions at 24, 48 and 72 h p.a. were lower than the value classified as irritating to the eyes by the Regulation (EC) No 1272/2008, therefore the substance is no classified for eye irritation hazard.