Reaction products of cyclohexylamine, alkan-1-amine and 1,1'-methanediylbis(4-isocyanatobenzene)

Endpoint summary

Description of key information

The potential of test item, to cause delayed contact hypersensitivity in guinea-pigs was assessed by the Magnusson-Kligman Maximisation Test based on OECD 406.

 

A significant response (slight erythema or a more marked reaction) was observed in 13/20 test and 4/10 control animals following challenge application of 30% w/v test item in propylene glycol. The nature of these observed reactions were similar in test and control animals, and were attributed principally to a primary irritant effect of test item when applied at this concentration. Challenge application of 5% w/v test item in propylene glycol caused a significant response in 6/20 test and 1/10 control animals. No significant responses were observed following challenge application of propylene glycol alone.

 

It was concluded that challenge with 30% test item had provoked an irritant response, and reactions to this challenge cannot be interpreted as a sensitization response. At the lower challenge concentration (5% test item: a sub-irritant concentration), the excess of responding animals in the test group over controls was equivalent to 20% of the test group. This is less than the EEC limit value (30%) for classification of a test substance as a skin sensitizer. Thus, although test item is a weak sensitizer, it is not classified as such under EEC criteria.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 July 1992 - 29 August 1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP study in accordance with recognised test guideline but: Lot/batch No.: not stated Expiration date of the lot/batch: not stated NOTE: study deemed acceptable because spectral data for test item are available, covering approximately before and after the test period - see section 1.4 Analytical Information.

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

1981

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

This study was carried out conducted in accordance with OECD 406 and in compliance with OECD GLP before 10 May 2017.

Specific details on test material used for the study:

Purity: Ca. 100%

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Olac Limited, Bicester, Oxfordshire, England
- Age at study initiation: 6 to 8 weeks
- Weight at study initiation: 340 - 483 g.
- Housing: Stainless steel cages with grid floors and tops (Type GP7/TR10 from Modular Systems and Development Company Limited, London, England). The grid floors ensured rapid removal of waste material to undertrays which were cleaned out as necessary. No more than five animals of the same sex were assigned to each cage.
- Diet (e.g. ad libitum): A commercially-available pelleted guinea-pig diet (Guinea-pig F.D.I., from Special Diets Services Limited, Witham, Essex, England) was fed without restriction.The diet contained no added antibiotic or other chemotherapeutic or prophylactic treatment. A regular supplement of autoclaved hay was also provided.
- Water (e.g. ad libitum): Animals had free access to tap water taken from the public supply
- Acclimation period: 6 - 16 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18°C, range 15º - 23ºC
- Humidity (%): 55%, range 40% - 70% RH.
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 / 12


IN-LIFE DATES: From: 29 July 1992 To: 29 August 1992

Route:

intradermal and epicutaneous

Vehicle:

propylene glycol

Concentration / amount:

Primary induction: 3% w/v in vehicle and 3% w/v in adjuvant, 0.1 mL
Secondary induction: 50% w/v in vehicle, 0.6 mL

Day(s)/duration:

Primary induction: Day 1; Secondary induction: Day 8

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Route:

epicutaneous, occlusive

Vehicle:

propylene glycol

Concentration / amount:

30%w/v in vehicle, 0.03 mL
5% w/v in vehicle, 0.03 mL

Day(s)/duration:

Day 22

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

10 per control group; 20 per treated group.

Details on study design:

RANGE FINDING TESTS:
Phase 1 - Intradermal induction
Four naive guinea-pigs received intradermal injections (0.1 mL) into the skin overlying the scapulae. Six injections were administered to each guinea-pig; three concentrations of test material in the selected vehicle and three in an emulsion of FCA. Two guinea-pigs received the maximum practicable concentration in each medium and two dilutions. The other two animals received three lower concentrations in each medium.
Reactions to treatment were assessed approximately 24 and 48 hours and 7 days after injection.

Phase 2 - Topical induction administration
Two guinea-pigs were subjected to a single intradermal injection of 0.1 mL FCA at least five days before topical application to simulate the FCA insult that the main study animals receive before topical induction. The hair was removed from both flanks of the two animals. Topical application of 0.4 mL of the maximum practicable concentration of the test material and three lower concentrations in the selected induction vehicle was administered to the four test sites on each guinea-pig. Each test formulation was applied to a 2 x 2 cm absorbent patch (Whatman No.3 filter paper) which was applied to the skin and covered by an occlusive dressing (Blenderm, Community Care Products, 3M Health Care, Loughborough, England and Elastoplast, T J Smith &Nephew Limited, Hull, England) for 48 hours.
Reactions to treatment were assessed 24 and 48 hours and 7 days after removal of the dressings.

Phase 3 - Topical challenge administration
Three guinea-pigs received a single intradermal injection of 0.1 mL FCA at least twenty days before topical application to simulate the FCA insult that the main study animals receive before challenge application. The hair was removed from both flanks of the three animals. Topical application of 0.03 mL of four concentrations of test material in the selected challenge vehicle was administered to the four test sites on each guinea-pig. Each test formulation was applied to a 1 cm diameter absorbent patch (AI-test, Imeco AB, Södertälje, Sweden) dressing (Blenderm and Elastoplast) for 24 hours.
Reactions to treatment were assessed 24 and 48 hours after removal of the dressings.

MAIN STUDY
The induction procedures were primary induction by intradermal injection on Day 1 and secondary induction by occluded topical application on Day 8. Dermal responses to primary and secondary induction were assessed approximately 24 hours and 48 hours after injection or removal of the occlusive dressings. For erythema, the more severe value for either the left or right injection site or for each temporal examination is reported.
- Primary induction:
Three pairs of injections (0.1 mL) were made deep into the dermis, such that on either side of the dorsal median line there were three injection sites in a row parallel to the spinal column. All injection sites lay near the periphery of a dermal test site 4 cm x 2 cm long, overlying the scapulae. The anterior and middle sites were positioned close together and distant from the posterior sites. Administrations with FCA (intradermal injections) were undertaken by injecting the appropriate concentration of test item in vehicle and then injecting 0.1 mL FCA emulsion as close to the first injection as possible. The two doses merged together intradermally; the sites had the overt appearance of having received a single administration.
- Secondary induction：
On Day 7, the clipped dorsa of all animals were subject to inunction with l0% w/v sodium lauryl sulphate in petrolatum. This was intended to enhance dermal absorption of formulations administered on the following day. On Day 8, the dermal site overlying the scapulae were treated by topical application of 0.6 mL of a test material formulation to test animals, while controls received 0.6 mL of the vehicle. Each dose was applied to a 4 x 2.5 cm absorbent patch (Whatman No. 3 filter paper) which was applied to the skin and covered by an occlusive dressing (Blenderm and Elastoplast) for 48 hours. The application site was wiped with a paper tissue moistened with the vehicle immediately after removal of the bandage.
- Challenge procedure:
Both flanks of all animals were clipped on Day 21 to expose areas (5 x 5 cm) on either side of the trunk. On Day 22 these areas were wet shaven to reveal a 5 x 5 cm area on the left flank and a 10 x 5 cm area on the right flank. Approximately one hour later the left site was treated by topical application of 0.03 mL of the vehicle while the right side received 0.03 mL of the maximum non-irritant concentration to one site and a dilution to a second site. The doses were applied to 1 cm diameter absorbent latches and covered by an occlusive dressing for 24 hours. The test site was wiped with a paper tissue moistened with vehicle immediately after removal of the bandage.
The challenge sites were examined approximately 24 and 48 hours of the occlusive dressings.

Challenge controls:

The control animals (Group 1) were treated identically to the test animals during the induction and challenge procedures, except that during induction the test material was replaced by vehicle.

Positive control substance(s):

no

Positive control results:

Not applicable.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

propylene glycol

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

Propylene glycol

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

Propylene glycol

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

propylene glycol

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

30% w/v test item in propylene glycol

No. with + reactions:

3

Total no. in group:

10

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

30% w/v test item in propylene glycol

No. with + reactions:

4

Total no. in group:

10

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

30% w/v test item in propylene glycol

No. with + reactions:

4

Total no. in group:

20

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

30% w/v test item in propylene glycol

No. with + reactions:

13

Total no. in group:

20

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

5% w/v test item in propylene glycol

No. with + reactions:

0

Total no. in group:

10

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

5% w/v test item in propylene glycol

No. with + reactions:

1

Total no. in group:

10

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

5% w/v test item in propylene glycol

No. with + reactions:

2

Total no. in group:

20

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5% w/v test item in propylene glycol

No. with + reactions:

5

Total no. in group:

20

Group:

positive control

Remarks on result:

not measured/tested

- Induction:

Principle dermal signs of reaction to treatment following intradermal injection of 3% w/v test item in either‘propylene glycol or propylene glycol in FCA were moderate erythema,eschar formation and pallor. Similar signs were observed for sites receiving FCA and/or propylene glycol alone. Occluded topical application of 50% w/v test item in propylene glycol gave rise to barely perceptible erythema,exfoliation and low incidences of slight erythema or eschar formation. A similar application of propylene glycol alone to control animals caused no erythematous reaction; exfoliation was observed in all animals.

- Challenge:

Challenge application of 30% w/v test item in propylene glycol gave rise to eschar formation or oedema in eight test and four control animals. A further five test animals showed slight erythema. Challenge application of 5% w/v test item in propylene glycol caused eschar formation in three test and no control animals; a further three test and one control animals showed slight erythema. Five test and one control animals showed barely perceptible erythema. Challenge application of propylene glycol alone gave rise to barely perceptible erythema in three test and one control animal.

- General health and bodyweight:

All animals remained in overt good health and generally achieved anticipated bodyweight gains during the study period.

Interpretation of results:

other: not sensitising

Conclusions:

Although the test item is a weak sensitiser, it is not classified as such under EEC criteria.

Executive summary:

The potential of test item to cause delayed contact hypersensitivity in guinea-pigs was assessed by the Magnusson-Kligman Maximisation Test according to OECD 406. The closely-clipped dorsa of ten male and ten female Dunkin-Hartley guinea-pigs were subject to intradermal injections of Freunds Complete Adjuvant, 3% w/v test item in propylene glycol and 3% w/v test item in propylene glycol in the adjuvant on Day 1. Seven days later the same area of skin was treated by topical application of 50% w/v test item in propylene glycol and the test site was covered by an occlusive dressing for 48 hours. The same induction procedures were carried out on a contemporaneous control group of five male and five female animals, except that the test material was replaced by vehicle in all doses. On Day 22, all animals were challenged by occluded application of propylene glycol to the left flank and 30% and 5% w/v test item in propylene glycol to two sites on the right flank. The occlusive dressings were removed on the following day and the condition of the test sites was assessed approximately 24 and 48 hours later.

 

Principal dermal signs of reaction following intradermal injection of 3% w/v test item in either propylene glycol or propylene glycol in FCA were moderate erythema, eschar formation and pallor. Topical induction application of 50% w/v test item in propylene glycol caused barely perceptible erythema and exfoliation.

 

A significant response (slight erythema or a more marked reaction) was observed in 13/20 test and 4/10 control animals following challenge application of 30% w/v test item in propylene glycol. The nature of these observed reactions were similar in test and control animals, and were attributed principally to a primary irritant effect of test item when applied at this concentration. Challenge application of 5% w/v test item in propylene glycol caused a significant response in 6/20 test and 1/10 control animals. No significant responses were observed following challenge application of propylene glycol alone.

 

It was concluded that challenge with 30% test item had provoked an irritant response, and reactions to this challenge cannot be interpreted as a sensitization response. At the lower challenge concentration (5% test item: a sub-irritant concentration), the excess of responding animals in the test group over controls was equivalent to 20% of the test group. This is less than the EEC limit value (30%) for classification of a test substance as a skin sensitizer. Thus, although test item is a weak sensitizer, it is not classified as such under EEC criteria.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Skin sensitisation:

OECD 406 test:

 Challenge with 30% test item had provoked an irritant response, and reactions to this challenge cannot be interpreted as a sensitization response. At the lower challenge concentration (5% test item: a sub-irritant concentration), the excess of responding animals in the test group over controls was equivalent to 20% of the test group.

Therefore in accordance with Regulation (EC) No. 1272/2008 (as amended by Regulation (EC) No. 286/2011) Table 3.4.2 and section 3.4.2.2.4.1, this substance should not be classified as skin sensitisers based on the test data.