2-[2-[4-[(2-cyanoethyl)methylamino]phenyl]vinyl]-1,3,3-trimethyl-3H-indolium dihydrogen phosphate

Endpoint summary

Description of key information

Not sensitising in guinea pig maximisation test.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation, other

Remarks:

in vivo (guinea pig maximisation test)

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Remarks:

Source study has reliability 2; details on the read-across approach are attached in section 13.

Principles of method if other than guideline:

Test based on method described by Magnusson B. and Kligman A.M. in 'Allergic contact dermatitis in the guinea pig: identification of contact allergens', C.C. Thomas, Springfield, Illinois, 1970.

GLP compliance:

no

Type of study:

guinea pig maximisation test

Species:

guinea pig

Strain:

other: Pribright white

Sex:

not specified

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Stock, Gelnhausen
- Housing: 10 animals per cage
- Diet: ad libitum
- Water: ad libitum

Route:

intradermal

Vehicle:

other: Freund's complete adjuvant 50 : 50 in distilled water.

Concentration / amount:

1 %

Day(s)/duration:

day 0

Route:

intradermal

Vehicle:

water

Concentration / amount:

1 %

Day(s)/duration:

day 0

Adequacy of induction:

other: highest non irritant concentration

Route:

epicutaneous, occlusive

Vehicle:

paraffin oil

Concentration / amount:

75 %

Day(s)/duration:

day 7 / exposure period 48 h

Adequacy of induction:

other: highest non irritant concentration

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

10 %

Day(s)/duration:

day 21 / exposure period 24 h

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

10 animals.

Details on study design:

RANGE FINDING TESTS: highest non irritating concentration tested and adopted for main test were: 1 % in distilled water for intradermal injection; 75 % in paraffin for dermal application; 10 % in distilled water for dermal challenge.

MAIN STUDY
A. INDUCTION EXPOSURE
Intradermal injection
- no. of exposure: 1.
- area: 4 × 6 cm on shaved shoulder.
- 3 types of injections, each in left and right side of the area: 1) Freund's complete adjuvant 50 : 50 with distilled water; 2) 1 % test substance in distilled water; 3) Freund's complete adjuvat 50 : 50 with 1 % test substance in distilled water.

Dermal application
- no. of exposure: 1.
- day of exposure: 7 days after intradermal injection.
- area: 3 × 6 cm.
- exposure period: 48 hours.
- concentration: 75 % in paraffin.
- coverage: closed.

B. CHALLENGE EXPOSURE
Dermal application
- day of challenge: 14 days after dermal application.
- exposure period: 24 hours.
- concentration : 10 % in distilled water.
- coverage: closed.
- site: left flank.
- evaluation: 24, 48 and 72 hours after challenge.

Positive control substance(s):

not specified

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

10 % in distilled water

No. with + reactions:

2

Total no. in group:

10

Clinical observations:

slight oedema

Remarks on result:

other: slight oedema.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

10 % in distilled water

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

other: 3rd reading

Hours after challenge:

72

Group:

test chemical

Dose level:

10 % in distilled water

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

animal	E = erythema O = oedema	observation time h
		24	48	72
1	E	0	0	0
	O	0	0	0
2	E	0	0	0
	O	0	0	0
3	E	0	0	0
	O	0	0	0
4	E	0	0	0
	O	0	0	0
5	E	0	0	0
	O	0	0	0
6	E	0	0	0
	O	1	0	0
7	E	0	0	0
	O	0	0	0
8	E	0	0	0
	O	0	0	0
9	E	0	0	0
	O	1	0	0
10	E	0	0	0
	O	0	0	0

Interpretation of results:

other: not classified according to the CLP Regulation (EC 1272/2008)

Conclusions:

The substance resulted as non sensitising in guinea pig maximisation test.

Executive summary:

Method

Guinea pig maximisation test according to method described by Magnusson and Kligman, 1970. Preliminary test allowed to choose concentrations for the main test. In particular, at day 0, induction was done by intradermal injection of test substance at 1 % concentration in distilled water and 50 : 50 distilled water and Freund's adjuvant; at day 7, induction was done by a 48 -h occlusive dermal application of test substance at 75 % concentration in paraffin ; at day 21, challenge was performed by a 24 -hour occlusive dermal application of test substance at 10 % in distilled water.

Results

Examination of treated areas was performed 24, 48 and 72 hours upon challenge exposure. 2/10 positive responses in terms of oedema were found at the 24-hour observation, then no positive responses were seen.

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

The substance is not classified according to the CLP Regulation (EC 1272/2008). In the guinea pig maximisation test (adjuvant type), a positive response in less than 30 % (classification range 30 - 60 %) of the treated animals was found upon intradermal induction of the test substance at concentrations of 1 %. The assessment was done 24, 48 and 72 h after the challenge. Therefore, the substance may not be attributed to a sensitising category and the result is considered as negative.