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Description of key information

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records
Reference
Endpoint:
skin irritation: in vivo
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1980
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study is well documented and performed similar to OECD 404 guideline.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
24 h exposure under occlusive conditions
GLP compliance:
no
Species:
rabbit
Strain:
Vienna White
Details on test animals or test system and environmental conditions:
TEST ANIMALS

- Weight at study initiation: females: 3.54 kg, males: 2.95


Type of coverage:
occlusive
Preparation of test site:
shaved
Vehicle:
water
Controls:
no
Amount / concentration applied:
0.5 g of 80 % aqueous solution
Duration of treatment / exposure:
24 hours
Observation period:
9 days
Number of animals:
3 male and 3 female
Irritation parameter:
erythema score
Basis:
mean
Time point:
other: 24, 72 hours
Score:
0.25
Max. score:
1
Reversibility:
fully reversible within: 72 hours
Irritation parameter:
edema score
Basis:
mean
Time point:
other: 24, 72 hours
Score:
0
Max. score:
0

time

animal 1

animal 2

animal 3

animal 4

animal 5

animal 6

erythema

24 h

1

1

0

0

0

1

72 h

0

0

0

0

0

0

9 d

0

0

0

0

0

0

edema

24 h

0

0

0

0

0

0

72 h

0

0

0

0

0

0

9 d

0

0

0

0

0

0

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: OECD GHS
Conclusions:
Monoammonium phosphate was slightly irritant to the rabbits skin in an in vivo study according to the methods of Draize.
According to the CLP-criteria no classification is justified.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2013-01-28 - 2013-02-25
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The GLP study was conducted according to an internationally accepted guideline. All study parameters are given in detail.
Qualifier:
according to guideline
Guideline:
other: Ocular Irritation Protocol: Neat Method (MTT ET-50) for use with EpiOcular TM Tis-sues, Rev: 17. Jan. 2012 by MatTek
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Species:
other: not applicable: in vitro method
Strain:
other: not applicable: in vitro method
Details on test animals or tissues and environmental conditions:
not applicable: in vitro method
Vehicle:
unchanged (no vehicle)
Controls:
other: not applicable: in vitro method
Amount / concentration applied:
3 minutes 30 minutes 60 minutes
102.0 mg 102.3 mg 99.8 mg
103.2 mg 104.0 mg 101.1 mg
Duration of treatment / exposure:
3, 30, 60 minutes
Number of animals or in vitro replicates:
not applicable: in vitro method
Details on study design:
On the day of the start of the experiment, the MTT concentrate was thawed. The concen-trate was diluted with the MTT solvent and the solution was stored at 4 °C in the dark.
The assay medium was warmed in the water bath to 37 °C.
The solid test item was ground.
Six sterile 6-well-plates were prepared with 0.9 mL assay medium in each well. The inserts containing the tissues were transferred to the wells using sterile forceps and the 6-well-plates were set into the incubator at 37 ± 1 °C, 5 ± 1 % CO2 for one hour pre-incubation.
Two 24-well-plates were prepared as holding plates. 12 wells of each plate were filled with 300 µL assay medium, the other 12 wells with 300 µL MTT medium. One additional plate was left empty. The plates were stored in the incubator.
After pre-incubation, the assay medium was replaced by fresh assay medium and the test is started. At the beginning of the experiment, a stop watch was started.
First the negative control (exposure time 60 min) was applied to two tissues, using 100 µL H2O demin. per tissue. Next, 100 mg of the solid test item were applied together with 30 µL H2O to two tissues (exposure time 60 min.). Then, two wells were used as positive control with 100 µL 0.3% Triton X 100 solution (exposure time 45 min.).After that 100 mg of the solid test item were applied together with 30 µL H2O to two tissues for 30 min exposure. Next, two tissues were used as positive control again with 100 µL 0.3 %Triton X 100 solution for 15 min. exposure. Last, 100 mg of the solid test item were applied together with 30 µL H2O in duplicate for a 3 min exposure time.
After the respective incubation times, the inserts were removed from the plates using ster-ile forceps. The inserts were thoroughly rinsed with DPBS and soaked for 10 minutes in 5 mL assay medium to remove any traces of the test item. They were finally blotted with sterile cellulose tissue for drying the inserts and set into the respective holding plate, using the wells containing assay medium. After transfer of all inserts, they were moved to the wells containing MTT solution, blotting the bottom with cellulose tissue again before setting the insert into the MTT well. The tissues were incubated with MTT medium for three hours. After this time, the MTT medium was aspirated and replaced by DPBS buffer. This was then aspirated, too, and replaced several times. At last, each insert was thoroughly dried and set into an empty 24-well-plate. Into each well, 2 mL isopropanol were pipetted, taking care to reach the upper rim of the insert. The plate was then covered with Parafilm® and left to stand overnight at room temperature.
On the next day, the inserts in which formazan had been produced were pierced with an injection needle, taking care that all colour was extracted.
The inserts were then discarded and the content of the 24-well plate was thoroughly mixed for 15 minutes on an orbital shaker in order to achieve homogenisation.
From each well, three replicates with 200 µL solution (each) were pipetted into a 96-well-plate which was read in a plate spectral photometer at 570 nm.
Irritation parameter:
other: percentage values of formazan production in comparison to the negative control
Basis:
mean
Time point:
other: 3 minutes
Score:
97.5
Reversibility:
not specified
Remarks on result:
other: test item
Irritation parameter:
other: percentage values of formazan production in comparison to the negative control
Basis:
mean
Time point:
other: 30 minutes
Score:
95.3
Reversibility:
not specified
Remarks on result:
other: test item
Irritation parameter:
other: percentage values of formazan production in comparison to the negative control
Basis:
mean
Time point:
other: 60 minutes
Score:
90.3
Reversibility:
not specified
Remarks on result:
other: test item
Irritation parameter:
other: percentage values of formazan production in comparison to the negative control
Basis:
mean
Time point:
other: 15 minutes
Score:
57.6
Reversibility:
not specified
Remarks on result:
other: positive control
Irritation parameter:
other: percentage values of formazan production in comparison to the negative control
Basis:
mean
Time point:
other: 45 minutes
Score:
23.6
Reversibility:
not specified
Remarks on result:
other: positive control

Mean Absorption Values:

Designation

Negative

control

Positive

control

Positive

control

Test item

Test

Item

Test

item

Incubation time

60 min.

15 min

45 min.

3 min.

30 min.

60 min.

Mean – blank (Tissue 1)

1.544

0.875

0.356

1.596

1.586

1.393

Mean – blank (Tissue 2)

1.693

0.989

0.407

1.562

1.500

1.531

Mean of the two Tissues

1.619

0.932

0.382

1.579

1.543

1.462

Relative Standard Deviation of the two tissues

6.5%

8.6%

9.4%

1.5%

3.9%

6.7%

For the test item and the positive control, the following percentage values of formazan production were calculated in comparison to the negative control:

% Formazan Production:

Designation

Positive

control

Positive

control

Test

item

Test

Item

Test

item

Incubation time

15 min

45 min.

3 min.

30 min.

60 min.

% Formazan production (Tissue 1)

54.0%

22.0%

98.6%

98.0%

86.0%

% Formazan production (Tissue 2)

61.1%

25.1%

96.5%

92.6%

94.6%

% Formazan production Mean

57.6%

23.6%

97.5%

95.3%

90.3%

From the percentage Formazan production the following ET50 value was calculated:

Positive control:      21.68 minutes

For the test item Magnesium Ammonium Phosphate (MAP, "Berliner Pflanze"):, no value could be calculated as no relative absorption below 50 % was observed at any exposition time. ET50 is therefore stated as“> 60 minutes”.

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test item Magnesium Ammonium Phosphate (MAP, "Berliner Pflanze") is considered as not/minimal irritant in the Human Cornea Model test.
Executive summary:

This study was performed in order to evaluate the potential of Magnesium Ammonium Phosphate (MAP, "Berliner Pflanze") to evoke eye irritation in a human cornea model in an in-vitro study.

The eye irritation test refers to the production of irreversible tissue damage following the application of a test material on a human cornea model.

Irritating materials are identified by their ability to produce a decrease in cell viability as determined, by using the MTT reduction assay below defined threshold levels at specified exposure periods.

The principle of the human cornea model assay is based on the hypothesis, that irritating chemicals are able to penetrate the epithelium by diffusion or erosion, and are cytotoxic to the underlying cell layers.

The test itemMagnesium Ammonium Phosphate (MAP, "Berliner Pflanze") was applied to a three-dimensional human cornea model tissue for three different exposure times in duplicate (3 min., 30 min. and 60 min.).

100 mg of the solid test item were applied to each tissue.

Deionised water was used as negative control, 0.3 % Triton X 100 solution was used as positive control.

After treatment, the respective substance was rinsed from the tissue; then, cell viability of the tissues was evaluated by addition of MTT which can be reduced to a blue formazan. Formazan production was measured by measuring the optical density (OD) of the resulting solution.

After treatment with the negative control, the absorbance values were well within the historical range and showed no cytotoxic effects. The positive control showed clear irritating effects for both treatment intervals.

After 3 minutes treatment with the test item, the relative absorbance values were reduced to 97.5 %. After 30 minutes treatment, relative absorbance values were reduced to 95.3 %. And after 60 minutes treatment, the relative absorbance values were reduced to 90.3 %.

 

From these values, the ET50was derived. The ET50of the test itemMagnesium Ammonium Phosphate (MAP, "Berliner Pflanze") is considered as “> 60 min” as after 60 minutes, absorption values of 90 % (compared with the negative control) were observed, lying far above 50 %.

 

Therefore, the test itemMagnesium Ammonium Phosphate (MAP, "Berliner Pflanze") is considered as

not/minimal irritant in the Human Cornea Model test.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

No data gaps were identified. The available data are adequate for risk assessment and classification and labelling purposes.


Justification for selection of skin irritation / corrosion endpoint:
In an in vivo skin irritation study similar to OECD 404 with monoammonium phosphate no signs of skin irritation were observed in rabbits. The study is judged as reliable and has Klimisch score 2.
Read-across justification:
For skin irritation read across from ammonium dihydrogenorthophosphate to magnesium ammonium phosphate is considered justified based on following background:
The only difference between the two inorganic salts is the replacement of two hydrogen atoms by magnesium. The removing of two H+ ions will not enhance the skin irritation potential of the substance.
In addition the different solubilities of the two compounds have to be taken into account. Ammonium dihydrogenorthophosphate is highly soluble in water (400 g/l) whereas magnesium ammonium phosphate is only poorly soluble (100 mg/l).
The key prerequisite for irritating properties of a substance is its solubility. Only the soluble proportion of a substance is able to cause relevant irritation either on skin or on the eyes.
Any reaction with skin humidity would be of minor importance in comparison to ammonium dihydrogenorthophosphate.
Any additional testing of magnesium ammonium phosphate for skin irritating properties would be therefore scientifically unjustified

Justification for selection of eye irritation endpoint:
In an in vitro eye irritation study with magnesium ammonium phosphate according to Ocular Irritation Protocol: Neat Method (MTT ET-50) for use with EpiOcular TM Tis-sues, Rev: 17. Jan. 2012 by MatTek the test item Magnesium Ammonium Phosphate (MAP, "Berliner Pflanze") was considered as not/minimal irritant in the Human Cornea Model test.
The study is GLP-compliant and has Klimisch score 1.

Justification for classification or non-classification

Skin Irritation:

According to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2007) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures

Magnesium ammonium phosphate is not classified as skin irritant.

Eye irritation:

According to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2007) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures

Magnesium ammonium phosphate is not classified as eye irritant.