Aluminium metaphosphate

Skin sensitisation

Administrative data

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

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).

Test material

Test material information

Constituent 1

Reference substance name:

Aluminium metaphosphate

EC Number:

237-415-3

EC Name:

Aluminium metaphosphate

Cas Number:

13776-88-0

Molecular formula:

Al.3HO3P

IUPAC Name:

aluminium metaphosphate

Details on test material:

- Name of test material (as cited in study report): Aluminium metaphosphate
- Physical state: white solid powder
- Analytical purity: >95%
- Purity test date: 13.03.2014
- Lot/batch No.: C08567A
- Expiration date of the lot/batch: 23.01.2017

In vivo test system

Test animals

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

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

unchanged (no vehicle)

Remarks:

moistened with distilled water for topical applications

Induction 2

Concentration / amount:

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

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Remarks:

moistened with distilled water for topical applications

Challenge 2

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)

Results and discussion

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).

In vivo (non-LLNA)

Results

Results 1

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.

Results 2

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.

Results 3

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.

Results 4

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.

Any other information on results incl. tables

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

Applicant's summary and conclusion

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.