Aluminium metaphosphate

Endpoint summary

Description of key information

One study is available for the substance to be registered. This study has been performed in accordance with a suitable guideline (OECD 406) and under the conditions of GLP.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

Study was performed before Annex VII of the REACH Regulation was updated in 2016.

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 May - 03 Jul 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Aluminium metaphosphate is an inorganic salt of the metal aluminium and metaphosphate (condensed orthophosphate). The water solubility of aluminium metaphosphate is low (31.5 mg/L at pH 7). Dermal absorption is therefore anticipated to be low (ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7c: Endpoint specific guidance. Version 2.0, November 2014). Based on the identity/chemical structure and physicochemical properties, testing for skin sensitisation by means of a Local Lymph Node Assay (OECD 429) is considered to be inappropriate, as it may underestimate the skin sensitising potential of the test substance, leading to a false negative result, due to a low dermal absorption and hence low exposure. For this reason, the Guinea Pig Maximization Test, which involves intradermal injection of the test substance for induction thus ensuring exposure beneath the skin surface, is considered to be the most appropriate method for assessing the skin sensitising potential of this particular substance.
The skin sensitising potential of aluminium metaphosphate was therefore evaluated in a Guinea Pig Maximization Test (GPMT) conducted in accordance with OECD Guideline 406 and GLP (Grümmer, 2014).

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River, Germany
- Age at study initiation: 4-6 weeks
- Weight at study initiation: 312.6-398.6 g
- Housing: in groups of up to ten
- Diet: commercial feeding mixture (Mühle Knull, Rostock, Germany), ad libitum
- Water: tap water (drinking quality, supplemented with 1 g/L vitamin C), ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3
- Humidity (%): 30-70
- Air changes (per hr): 16
- Photoperiod (hrs dark / hrs light): 12/12

Route:

intradermal and epicutaneous

Vehicle:

unchanged (no vehicle)

Remarks:

moistened with distilled water for topical applications

Concentration / amount:

Intradermal induction: 2.5% suspension in distilled water
Epicutaneous induction: 100% (moistened with distilled water)
Epicutaneous challenge: 100% (moistened with distilled water)

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Remarks:

moistened with distilled water for topical applications

Concentration / amount:

Intradermal induction: 2.5% suspension in distilled water
Epicutaneous induction: 100% (moistened with distilled water)
Epicutaneous challenge: 100% (moistened with distilled water)

No. of animals per dose:

5 (control group) and 10 (test group)

Details on study design:

RANGE FINDING TESTS: The appropriate concentrations of the test material and the appropriate vehicle for the intradermal induction phase, topical induction phase and challenge phase were determined on additional 6 FCA (Freund’s Complete Adjuvant) treated animals.
The irritation response to intradermal injections of various concentrations of the test substance was examined in three guinea pigs. An area of the flanks was clipped free from hair with electric clippers. Amounts of 0.1 mL of selected test concentrations (5, 2.5, 1 and 0.5% suspensions of the test material in distilled water) were applied by intradermal injection.
24 and 48 h after injection, the animals were examined for signs of irritation according to the Magnusson and Kligman Grading Scale.
The concentration of 2.5% of the test material in distilled water (suspension) was systemically well-tolerated and caused a mild-moderate skin irritation. Therefore, this concentration was used for the main test (intradermal induction phase).
The irritation response to topical treatment of various concentrations of the test substance was examined in three further guinea pigs. The flanks of the animals were clipped. Filter paper fully-loaded with the test substance (100, 50 and 25 in distilled water) was attached to the skin of the guinea pigs and held in contact by an occlusive dressing for 24 h.
The animals were observed and examined for signs of irritation according to the Magnusson and Kligman Grading Scale approximately 24 and 48 h after removing the test material.
The concentration of 100% of test material moistened with distilled water was systemically well-tolerated and did not cause skin irritation. Therefore, this concentration was used for the main test (topical induction phase).
Because the test material was non-irritating, the skin of the test animals was pre-treated with 10% sodium lauryl sulphate in vaseline for 24 h.
For the challenge phase, a concentration of 100% of the test material moistened with distilled water was used. This concentration was systemically well-tolerated and did not cause skin irritation.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal and epicutaneous, respectively)
- Exposure period: single injection (intradermal) and 48 h (epicutaneous)
- Test groups:
Intradermal (3 pairs of injections 0.1 mL):
Injection 1: 1:1 mixture (v/v) FCA/water
Injection 2: test substance
Injection 3: test substance in a 1:1 mixture (v/v) FCA/water
Epicutaneous: test substance moistened with distilled water
- Control group:
Intradermal (3 pairs of injections, each 0.1 mL):
Injection 1: 1:1 mixture (v/v) FCA/water
Injection 2: water
Injection 3: 1:1 mixture (v/v) FCA/water
Epicutaneous: water
- Site: anterior dorsal region of the thorax
- Frequency of applications: single
- Duration: Days 0-8 (on Day 6, one day prior to epicutaneous induction, the clipped skin of all animals in each group was treated with 10% sodium lauryl sulphate in vaseline)
- Concentrations: 2.5% suspension in distilled water (intradermal) and 100% moistened with distilled water (epicutaneous)

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 20
- Exposure period: 24 h
- Test groups: test substance
- Control group: test substance
- Site: flanks
- Concentrations: 100% moistened with distilled water
- Evaluation (hr after challenge): 48 and 72 h

Positive control substance(s):

yes

Remarks:

hexyl cinnamic aldehyde (CAS No 101-86-0, routinely evaluated every 6 months)

Positive control results:

Hexyl cinnamic aldehyde induced skin sensitisation reactions in 90% of the treated animals after challenge (intradermal induction: 5% in paraffin oil; topical induction: 75% in vaseline; challenge: 55% in vaseline).

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

induction (intradermal): 0%; induction (epicutaneous): 0%; challenge: 100%

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: induction (intradermal): 0%; induction (epicutaneous): 0%; challenge: 100%. No with. + reactions: 0.0. Total no. in groups: 5.0.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

induction (intradermal): 0%; induction (epicutaneous): 0%; challenge: 100%

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: induction (intradermal): 0%; induction (epicutaneous): 0%; challenge: 100%. No with. + reactions: 0.0. Total no. in groups: 5.0.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

induction (intradermal): 2.5%; induction (epicutaneous): 100%; challenge: 100%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: induction (intradermal): 2.5%; induction (epicutaneous): 100%; challenge: 100%. No with. + reactions: 0.0. Total no. in groups: 10.0.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

induction (intradermal): 2.5%; induction (epicutaneous): 100%; challenge: 100%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: induction (intradermal): 2.5%; induction (epicutaneous): 100%; challenge: 100%. No with. + reactions: 0.0. Total no. in groups: 10.0.

Animal weights

Table 3: Individual animal weights (g) at start / test end (test group)

Animal	Test start	Test end	Body weight change
1	391.7	464.9	73.2
2	348.4	448.9	100.5
3	398.6	531.7	133.1
4	376.0	479.1	103.1
5	357.8	464.8	107.0
6	387.6	455.5	67.9
7	393.4	491.3	97.9
8	375.8	455.4	79.6
9	356.1	446.1	90.0
10	377.3	494.3	117.0

 

Individual weight of control group

Table 4: Individual animal weights (g) at test start and at test end (control group)

Animal	Test start	Test end	Body weight change
K1	379.9	456.5	76.6
K2	358.1	446.8	88.7
K3	332.3	454.7	122.4
K4	324.0	420.2	96.2
K5	312.6	395.8	83.2

 

Table 5: Skin reactions of test animals after treatment with the test material

Animal	Numerical grading after
	24 h	48 h
1	0	0
2	0	0
3	0	0
4	0	0
5	0	0
6	0	0
7	0	0
8	0	0
9	0	0
10	0	0

 

Table 6: Skin reactions of control animals after treatment with the test material

Animal	Numerical grading after
	24h	48h
K1	0	0
K2	0	0
K3	0	0
K4	0	0
K5	0	0

 

Table 7: Skin reactions of animals after challenge treatment with HCA 55 % in vaseline

Animal	Numerical grading after
	24 h	48 h
1	1	1
2	0	0
3	1-2	1-2
4	1	1
5	1-2	2
6	1	1
7	1-2	1-2
8	0-1	1
9	1-2	1
10	1	1

Interpretation of results:

GHS criteria not met

Conclusions:

The test material did not induce any skin reactions in intradermally and topically induced guinea pigs after challenge treatment. Therefore, the material does not fulfil the criteria for classification according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), and is thus considered to be not skin sensitising.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In accordance with Annex VII, Section 8.3, Column 2 of Regulation (EC) No 1907/2006 (REACH), the Murine Local Lymph Node Assay (LLNA) is the first-choice method for in vivo testing of skin sensitisation. Only in exceptional circumstances should another test be used. Justification for the use of another test shall be provided.

Paragraphs 4 and 5 of OECD Guideline 429 (as adopted on 22 July 2010) read as follows:

“4. The LLNA provides an alternative method for identifying potential skin sensitizing test substances. This does not necessarily imply that in all instances the LLNA should be used in place of guinea pig tests (i.e. TG 406) […], but rather that the assay is of equal merit and may be employed as an alternative in which positive and negative results generally no longer require further confirmation. The testing laboratory should consider all available information on the test substance prior to conducting the study. Such information will include the identity and chemical structure of the test substance; its physicochemical properties; the results of any other in vitro or in vivo toxicity tests on the test substance and toxicological data on structurally related test substances. This information should be considered in order to determine whether the LLNA is appropriate for the test substance (given the incompatibility of limited types of test substances with the LLNA- see paragraph 5) and to aid in dose selection.

5. The LLNA is an in vivo method and, as a consequence, will not eliminate the use of animals in the assessment of allergic contact sensitizing activity. It has, however, the potential to reduce the number of animals required for this purpose. Moreover, the LLNA offers a substantial refinement (less pain and distress) of the way in which animals are used for allergic contact sensitization testing. The LLNA is based upon consideration of immunological events stimulated by chemicals during the induction phase of sensitization. Unlike guinea pig tests (i.e. TG 406) […] the LLNA does not require that challenge-induced dermal hypersensitivity reactions be elicited. Furthermore, the LLNA does not require the use of an adjuvant, as is the case for the guinea pig maximisation test […]. Thus, the LLNA reduces animal pain and distress. Despite the advantages of the LLNA over TG 406, it should be recognised that there are certain limitations that may necessitate the use of TG 406 […] (e.g. false negative findings in the LLNA with certain metals, false positive findings with certain skin irritants [such as some surfactant type chemicals] […], or solubility of the test substance). In addition, test substance classes or substances containing functional groups shown to act as potential confounders […] may necessitate the use of guinea pig tests (i.e. TG 406) […]. Further, based on the limited validation database, which consisted primarily of pesticide formulations, the LLNA is more likely than the guinea pig test to yield a positive result for these types of test substances […]. However, when testing formulations, one could consider including similar test substances with known results as benchmark test substances to demonstrate that the LLNA is functioning properly […]. Other than such identified limitations, the LLNA should be applicable for testing any test substances unless there are properties associated with these test substances that may interfere with the accuracy of the LLNA.”

Aluminium metaphosphate is an inorganic salt of the metal aluminium and metaphosphate (condensed orthophosphate). The water solubility of aluminium metaphosphate is low (31.5 mg/L at pH 7). Dermal absorption is therefore anticipated to be low (ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7c: Endpoint specific guidance. Version 2.0, November 2014). Based on the identity/chemical structure and physicochemical properties, testing for skin sensitisation by means of a Local Lymph Node Assay (OECD 429) is considered to be inappropriate, as it may underestimate the skin sensitising potential of the test substance, leading to a false negative result, due to a low dermal absorption and hence low exposure. For this reason, the Guinea Pig Maximization Test, which involves intradermal injection of the test substance for induction thus ensuring exposure beneath the skin surface, is considered to be the most appropriate method for assessing the skin sensitising potential of this particular substance.

The skin sensitising potential of aluminium metaphosphate was evaluated in a Guinea Pig Maximization Test (GPMT) conducted in accordance with OECD Guideline 406 and GLP (Grümmer, 2014). Preliminary tests were conducted to determine the test substance concentrations for intradermal and epicutaneous applications in the main study. Test animals (10 female Dunkin Hartley guinea pigs) were intradermally induced with the test substance as a 2.5% suspension in water (Day 0), and topically induced with the test substance at 100% moistened with water (Day 7) for 48 h. Control animals (5 females) were treated similarly with distilled water. Control and test animals were challenged by topical application of the test substance at 100% moistened in water (Day 20) for 24 h. For topical induction and challenge applications, the skin of the test animals was pre-treated with 10% sodium lauryl sulphate in vaseline for 24 h, respectively. Skin reactions were examined and evaluated 24 and 48 h after challenge patch removal (i.e. 48 and 72 h after challenge application). No skin reactions were noted at the challenge sites of the control and test animals at the observation time points. Hence, the test material did not induce any skin reactions in intradermally and topically induced guinea pigs after challenge treatment.

Therefore, the test material does not fulfil the criteria for classification according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), and is thus considered to be not skin sensitising.

Migrated from Short description of key information:
Skin sensitisation: not sensitising (OECD 406 (GPMT), GLP)

Justification for selection of skin sensitisation endpoint:
Only one study available (OECD Guideline and GLP)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

This information is not available.

Migrated from Short description of key information:
Respiratory sensitisation: no study available

Justification for classification or non-classification

The available data indicate that the substance does not meet the classification criteria in accordance with Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

CLP

Skin sensitisation: not classified

Respiratory sensitisation: data lacking

GHS

Skin sensitisation: not classified

Respiratory sensitisation: data lacking