reaction mass of calcium bis(dihydrogenorthophosphate) and calcium hydrogenorthophosphate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

No data.

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

abstract

Remarks:

.

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See read-across justification report under Section 13 ‘Assessment Reports’.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In accordance with REACH Annex XI, Section 1.5, of Regulation (EC) No. 1907/2006 (REACH) the standard testing regime may be adapted in cases where a grouping or read-across approach has been applied.

The similarities may be based on:
(1) a common functional group
(2) the common precursors and/or the likelihood of common breakdown products via physical or biological processes, which result in structurally similar chemicals; or
(3) a constant pattern in the changing of the potency of the properties across the category

(1) All salts are inorganic phosphates, composed of a phosphate anion and a calcium cation.
(2) All members of the group will ultimately dissociate into the common breakdown products of the Ca2+ cation and the PO43-anion.
(3) A number of studies are provided to show that monovalent calcium and/or magnesium inorganic orthophosphates exhibit low acute oral toxicity. These data are provided in Section 7.2.1 of this dossier. The information provided in these records is considered to be of suitable relevance and reliability to underpin the read across for the acute dermal and inhalation endpoints. All substances are ionic and will readily dissociate to their ionic forms in aqueous environments. The orthophosphate ion can undergo ionisation with loss of H+ from each of the three –OH groups and therefore can occur in the -1, -2 or -3. The degree of ionisation is dependent upon the associated cation and the ambient pH (if in solution). Calcium and phosphate are key elements in various cellular processes their import and export over cell membranes is regulated via pore systems and usually tightly regulated. Orthophosphate salts of these types are not considered to differ in their systemic toxicity profiles. Differences arise in their local effects profile due differences in pH and buffering capacities. This does not have an effect on systemic toxicity.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See read-across justification report under Section 13 ‘Assessment Reports’.

3. ANALOGUE APPROACH JUSTIFICATION
See read-across justification report under Section 13 ‘Assessment Reports’.

4. DATA MATRIX
See read-across justification report under Section 13 ‘Assessment Reports’.

Data source

Reference

Reference Type:

secondary source

Title:

No information

Author:

Parent R

Year:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: No data.

Deviations:

not applicable

Principles of method if other than guideline:

Ten male New Zealand White rabbits (five/dose) were treated with 20 mg/kg or 300 mg/kg of test material. The test material was moistened with saline and placed in contact with the skin for 24 hr under an occlusive wrap. Animals were observed for signs of toxicity daily.

GLP compliance:

not specified

Test type:

other: No data.

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

monocalcium phosphate monohydrate

IUPAC Name:

monocalcium phosphate monohydrate

Constituent 2

Reference substance name:

10031-30-8

EC Number:

600-059-8

Cas Number:

10031-30-8

IUPAC Name:

10031-30-8

Details on test material:

- Name of test material (as cited in study report): Monocalcium phosphate monohydrate.

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male

Details on test animals or test system and environmental conditions:

No data.

Administration / exposure

Type of coverage:

occlusive

Vehicle:

other: No vehicle, the test material was moistened with saline.

Details on dermal exposure:

No data.

Duration of exposure:

24 hr

Doses:

20 mg/kg and 300 mg/kg

No. of animals per sex per dose:

Five animals per dose.

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Animals were observed for signs of toxicity daily.

Statistics:

No data.

Results and discussion

Preliminary study:

No data.

Effect levels

Sex:

male

Dose descriptor:

other: Minimal lethal dose

Effect level:

> 300 mg/kg bw

Based on:

not specified

Mortality:

There were no deaths during the 14 day observation period.

Clinical signs:

other: No data.

Gross pathology:

No data.

Other findings:

No data.

Any other information on results incl. tables

No data.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

The test material, when administered at a maximum dose of 300 mg/kg produced no deaths during the 14 day observation period. The test material was described as practically non-toxic.
Study is not a true dermal toxicity tests but results are reported from an irritation study. The LD50 value of >300 mg/kg bw, is the the highest dose tested and as such the results are not suitable for use for classification and labelling.