Neodymium trichloride

Endpoint summary

Description of key information

Skin Sensitisation

In conclusion, under the conditions of this study the test material is not classified as a skin sensitiser.

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:

20 March 2017 to 27 April 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Soluble rare earth substances are known to give false positives in the LLNA studies.

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Batch No.of test material: NDCL16-60
- Expiration date of the lot/batch: 09 February 2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: 4 to 5 weeks old
- Weight at study initiation: 327 to 396 g
- Housing: in groups of up to 3 in polycarbonate containers, the flooring of which was covered with dust-free cuttings and the top fitted with a stainless steel lid with a feeding device and drinking device of 500 mL.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: minimum of 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19 to 25°C
- Humidity: 30 to 70%
- Air changes: at least 10 per hour
- Photoperiod: lighting was controlled by a time switch to give twelve hours continuous light (07.00 to 19.00) and twelve hours darkness.

Route:

other: intradermal and topical

Vehicle:

other: physiological saline (intradermal) and water (topical)

Concentration / amount:

0.02 % w/v (intradermal) and 80 % w/v (topical)

Day(s)/duration:

Intradermal induction took place on Day 0. On Day 8, animals received a topical induction application which was covered for 48 hours.

Adequacy of induction:

non-irritant substance, but skin pre-treated with 10% SDS

No.:

#1

Route:

other: topical

Vehicle:

water

Remarks:

distilled

Concentration / amount:

10 % and 20 % (1 sample cup)

Day(s)/duration:

14 days after the topical induction dose (Day 21), animals were exposed to the challenge dose for 24 hours.

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Group 1 (Negative control): n=5
Group 2 (Treatment group): n=10

Details on study design:

PRELIMINARY TESTS:

-Determination by intradermal injection of the Maximal Non Necrotizing Concentration (MNNC):
This test was conducted for the purpose of defining a MNNC of the test material which, on intradermal injection during the induction phase, does not risk causing too great a lesion (non-necrotizing concentration), should be well-tolerated systemically and should be the highest to cause mild-to-moderate skin irritation.
Two animals received a volume of 0.1 mL of the test material, on both sides of the spine, at 4 concentrations: diluted at 60, 40, 20 and 5% in physiological saline in view to determine the MNNC. A macroscopic evaluation of the cutaneous reactions was conducted 24 hours after the injections. Due to the necrosis observed in the animals, the same animals received a volume of 0.1 mL of the test material, on both sides of the spine at 4 new concentrations: diluted at 2, 1, 0.5 and 0.2% in physiological saline in view to determine the MNNC. A macroscopic evaluation of the cutaneous reactions was conducted 24 hours after the injections. Due to the necrosis observed in the animals, the same animals received a volume of 0.1 mL of the test material, on both sides of the spine at 4 new concentrations: diluted at 0.1, 0.05, 0.02 and 0.01% in physiological saline in view to determine the MNNC. A macroscopic evaluation of the cutaneous reactions was conducted 24 hours after the injections.

- Determination by topical application of the Pre-Maximal Non Irritant Concentration (Pre-MNIC):
This test, which allowed evaluating the irritancy potential of the test material, defined whether an application of sodium lauryl sulphate would be needed during topical induction phase.
The test material was applied on the dorso-lumbar zone of two guinea pigs shorn beforehand, with occlusive dressing for 24 hours, at 4 different concentrations: diluted at 80, 50, 30 and 20% in distilled water. After the removal of the occlusive dressing, the treated areas were rinsed with distilled water. A macroscopic evaluation of the cutaneous reactions was conducted 24 hours after removal of the dressing.

- Determination by topical application of the Maximal Non Irritant Concentration (MNIC):
This test was carried out for the purpose of determining the MNIC of the test material without risk of an irritant effect during the challenge phase.
Three guinea pigs were treated according to the same treatment as animals from GROUP 1 (control) for the induction phase (i.e. physiological saline and distilled water). During the challenge phase, the animals were treated with the test material placed onto the selected treatment sites and covered with an occlusive dressing for a period of 24 hours at 4 different concentrations: diluted at 80, 70, 60 and 50% in distilled water. After the removal of the occlusive dressing, the treated areas were rinsed with distilled water. A macroscopic evaluation of the cutaneous reactions was conducted 24 and 48 hours after removal of the occlusive dressing. Due to the results, the same animals were treated with the test material placed onto the selected treatment sites and covered with an occlusive dressing for a period of 24 hours at 4 new different concentrations: diluted at 40, 20, 10 and 5% in distilled water. A macroscopic evaluation of the cutaneous reactions was conducted 24 and 48 hours after removal of the occlusive dressing.

MAIN STUDY

A. INDUCTION EXPOSURE

- Intradermal induction
Day 0: After shearing the scapular zone, three pairs of intradermal injections (ID) of 0.1 mL were performed on the scapular zone in such a way as an injection on each pair is placed to either side of the spine as follows:
GROUP 1 (control):
2 ID: Freund’s Complete Adjuvant diluted at 50% in physiological saline
2 ID: physiological saline
2 ID: a mixture with equal volumes v/v:
- Freund’s Complete Adjuvant at 50% and physiological saline

GROUP 2 (Treated):
2 ID: Freund’s Complete Adjuvant diluted at 50% in physiological saline
2 ID: test material at 0.02% in physiological saline
2 ID: a test mixture in equal volumes v/v:
- Freund’s Complete Adjuvant at 50 % and the test material at 0.04% in physiological saline

- Topical induction
Day 7: The scapular zone of all the animals in each group, shorn beforehand, was brushed with a solution of sodium lauryl sulphate at 10% in thick Vaseline, in order to create a local irritation.
Day 8: A topical application under occlusive dressing (25 mm x 25 mm non-woven swab of 4-layer patch held in contact with the skin by means of 50 mm wide hypoallergenic adhesive tape) for 48 hours was performed on the injection sites of each animal:
GROUP 1 (control): 0.5 mL of distilled water.
GROUP 2 (treated): 0.5 mL of the test material at 80% in distilled water.
Day 10: Removal of the semi-occlusive dressing.

- Rest phase: The animals of both groups were left for 10 days.

B. CHALLENGE EXPOSURE
Day 21: The experimental procedure of this phase was identical for both groups submitted to this experimentation: on the previously shorn dorso-lumbar zone, an application, under occlusive dressing, was applied for 24 hours:
- 1 sample cup saturated with the test material at 20 % (MNIC) and 1 sample cup saturated with the test material at 10% in distilled water (1/2 MNIC).
Day 22: After the removal of the occlusive dressing, the treated areas were rinsed with distilled water.
Day 23: 1st reading time – 24 hours after the patch removal.
Day 24: 2nd reading time – 48 hours after the patch removal.

INTERPRETATION OF RESULTS
The test material will be regarded as a sensitiser if 30% or more of the test animals show a sensitisation response:
Sub-category 1A: ≥ 30 % responding at ≤ 0.1 % intradermal induction dose or ≥ 60 % responding at > 0.1 % to ≤ 1 % intradermal induction dose
Sub-category 1B: ≥ 30 % to < 60 % responding at > 0.1 % to ≤ 1 % intradermal induction dose or ≥ 30 % responding at > 1 % intradermal induction dose

Challenge controls:

Yes, administered the test material in distilled water at a challenge concentration of 20 and 10% w/v

Positive control substance(s):

yes

Remarks:

α-hexylcinnamaldehyde

Positive control results:

Under these experimental conditions, the reference substance a-Hexylcinnamaldehyde must be classified in category 1 “Skin sensitisation” sub-category 1B in accordance with the Regulation EC No. 1272/2008 on classification, labelling and packaging of substances and mixtures. The signal word “Warning” and hazard statement H317 “May cause an allergic skin reaction” are required.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

10 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

20 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

10 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

20 %

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

10 %

No. with + reactions:

0

Total no. in group:

5

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

20 %

No. with + reactions:

0

Total no. in group:

5

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

10 %

No. with + reactions:

0

Total no. in group:

5

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

20 %

No. with + reactions:

0

Total no. in group:

5

PRELIMINARY STUDIES

 

- MNNC determination:

Necrosis in all animals was observed at the tested concentrations of 60, 40, 20 and 5%. In view of these results, another MNNC determination was carried out at the tested concentrations of 2, 1, 0.5 and 0.2%.

24 hours after the injections, necrosis was observed in all animals at the tested concentrations of 2, 1, 0.5 and 0.2%.

In view of these results, another MNNC determination was carried out at the tested concentrations of 0.1, 0.05, 0.02 and 0.01%.

24 hours after the injections, necrosis was observed in one animal (1/2) at the tested concentration of 0.1% and slight necrosis was observed in the other animal. Slight necrosis was observed in all animals at the tested concentration of 0.05%. Discrete erythema was noted in the animals at the tested concentrations of 0.02 and 0.01%. The first induction of the Group 2 was carried out by intradermal injection at the maximal non necrosing concentration of 0.02%.

 - Pre MNIC determination:

24 hours after the removal of the occlusive dressings, no cutaneous reaction was observed whatever the tested concentration. In view of these results, the concentration selected was 80% for the 2nd induction of the Group 2 and the MNIC determination began at the concentration of 80%.

- MNIC determination:

24 hours after the removal of the occlusive dressings, moderate to intense erythema was notedat the tested concentrations of 80, 70, 60 and 50%.

48 hours after the removal of the occlusive dressings, discrete to moderate erythema associated with dryness of the skin was notedat the tested concentrations of 80, 70, 60 and 50%.

In view of these results, another MNIC determination was carried out at the tested concentrations of 40, 20, 10 and 5%.

24 hours after the removal of the occlusive dressings, discrete erythema was noted in the animals at the tested concentrations of 40% and no cutaneous reaction was noted at the tested concentrations 20, 10 and 5%.

48 hours after the removal of the occlusive dressings, no cutaneous reaction was noted whatever the tested concentration. In view of this result, the concentrations selected were 20% (MNIC) and 10% (1/2 MNIC) for the challenge phase.

 

MAIN STUDY

-Induction phase Group 2: Discrete erythema was noted in four animals (4/10) and no cutaneous reaction was noted in six animals (6/10) 24 hours after the first induction. Discrete erythema associated with dryness of the skin was noted in all animals (10/10) after the second induction.

- Induction phase Group 1: No cutaneous reaction was noted 24 hours after the first induction. Dryness of the skin was noted in all animals (5/5) after the second induction.

- Challenge phase Groups 1 & 2: Overall results of the challenge phase with the test material (readings at 24 and 48 hours) are given in Table 1.

In the treated group (treatment dose of 20%), no macroscopic cutaneous reactions attributable to allergy were noted after the challenge phase. In the control group (associated with the treatment dose of 20%), no macroscopic cutaneous intolerance reactions were recorded after the challenge phase.

In the treated group (treatment dose of 10%), no macroscopic cutaneous reactions attributable to allergy were noted after the challenge phase. In the control group (associated with the treatment dose of 10%), no macroscopic cutaneous intolerance reactions were recorded after the challenge phase.

 

WEIGHT EVOLUTION

No abnormality was recorded in the body weight gain of both groups.

MORTALITY

No mortality was registered during the main test.

Table 1: Macroscopic evaluation (readings at 24 and 48 hours) of cutaneous reactions

Groups	Reading time	Concentrations	Incidence				% of positive responses ≥ 1	% of animal sensitised
			0	1	2	3
Group 1 Control	24 h	20 %	5	0	0	0	0	-
	48 h	20 %	5	0	0	0	0	-
	24 h	10 %	5	0	0	0	0	-
	48 h	10 %	5	0	0	0	0	-
Group 2 Treated	24 h	20 %	10	0	0	0	0	0
	48 h	20 %	10	0	0	0	0	0
	24 h	10 %	10	0	0	0	0	0
	48 h	10 %	10	0	0	0	0	0

 

Grading scale

0 = No visible change

1 = Discrete or patchy erythema

2 = Moderate and confluent erythema

3 = Intense erythema and swelling

Interpretation of results:

other: Not sensitising in accordance with EU criteria

Conclusions:

Under the conditions of the study, the test material is not considered to be a skin sensitiser.

Executive summary:

The potential of the test material to cause sensitisation was determined in accordance with the standardised guidelines OECD 406 and EU Method B6 under GLP conditions using the guinea pig maximisation test.

According to the results of the pre-tests, the test material was applied to 10 Guinea pigs during the induction phase (intradermic injection at 0.02% and topical application at 80%). During the challenge phase, animals received a topical application of test material (diluted at 20% and 10% in distilled water) under an occlusive dressing for a period of 24 hours.

In the treated group (treatment dose of 20%), no macroscopic cutaneous reactions attributable to allergy were noted after the challenge phase. In the control group (associated with the treatment dose of 20%), no macroscopic cutaneous intolerance reactions were recorded after the challenge phase.

In the treated group (treatment dose of 10%), no macroscopic cutaneous reactions attributable to allergy were noted after the challenge phase. In the control group (associated with the treatment dose of 10%), no macroscopic cutaneous intolerance reactions were recorded after the challenge phase.

The results of the positive control test validate the test.

In conclusion, under the conditions of this study the test material is not classified as a skin sensitiser.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The potential of the test material to cause sensitisation was determined in accordance with the standardised guidelines OECD 406 and EU Method B6 under GLP conditions using the guinea pig maximisation test. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

According to the results of the pre-tests, the test material was applied to 10 Guinea pigs during the induction phase (intradermic injection at 0.02% and topical application at 80%). During the challenge phase, animals received a topical application of test material (diluted at 20% and 10% in distilled water) under an occlusive dressing for a period of 24 hours.

In the treated group (treatment dose of 20%), no macroscopic cutaneous reactions attributable to allergy were noted after the challenge phase.In the control group (associated with the treatment dose of 20%), nomacroscopiccutaneous intolerance reactions were recorded after the challenge phase.

In the treated group (treatment dose of 10%), no macroscopic cutaneous reactions attributable to allergy were noted after the challenge phase.In the control group (associated with the treatment dose of 10%), nomacroscopiccutaneous intolerance reactions were recorded after the challenge phase.

The results of the positive control test validate the test.

In conclusion, under the conditions of this study the test material is not classified as a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance does not require classification with respect to skin sensitisation.