Calcium hydrogenorthophosphate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1973

Report date:

1973

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The diluted compound was applied in increasing doses at increments of 0.2 fractional log intervals to the closely clipped, intact skin of New Zealand white male and female rabbits. The treated areas were covered with plastic strips and the animals held in wooden stocks for periods up to twenty-four hours, after which time they were assigned to individual cages. Observations were made for toxic signs and the viscera of the test animals were examined macroscopically.

GLP compliance:

no

Remarks:

study predates GLP

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

calcium hydrogenphosphate dihydrate

IUPAC Name:

calcium hydrogenphosphate dihydrate

Constituent 2

Reference substance name:

Calcium hydrogenorthophosphate

EC Number:

231-826-1

EC Name:

Calcium hydrogenorthophosphate

Cas Number:

7757-93-9

Molecular formula:

CaHPO4

IUPAC Name:

calcium hydrogen phosphate

Details on test material:

- Name of test material (as cited in study report): Dicalcium phosphate dihydrate
- Analytical purity: no data

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

No data pertinent to environmental conditions.
The animals were albinos.

Administration / exposure

Type of coverage:

occlusive

Vehicle:

corn oil

Details on dermal exposure:

TEST SITE
- Area of exposure: no data
- % coverage: no data
- Type of wrap if used: plastic strips

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no data
- Time after start of exposure: no data

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 13.026g, 19.056g, 20.644g
- Concentration (if solution): 40.0% suspension
- Constant volume or concentration used: no
- For solids, paste formed: yes

VEHICLE
- Amount(s) applied (volume or weight with unit): no data
- Concentration (if solution): no data
- Lot/batch no. (if required): no data
- Purity: no data

Duration of exposure:

24 h

Doses:

5010 mg/kg bw; 7940 mg/kg bw

No. of animals per sex per dose:

5010 mg/kg bw - 1 female
7940 mg/kg bw - 1 female, 1 male

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: surviving animals were sacrificed 14 days after dosing.
- Frequency of observations and weighing: Bodyweight was recorded 5 days after dosing. There is no other data for observations.
- Necropsy of survivors performed: yes
- Other examinations performed: observations were made for toxic signs and the viscera were examined macroscopically.

Statistics:

not applicable

Results and discussion

Preliminary study:

not applicable

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 7 940 mg/kg bw

Based on:

test mat.

Mortality:

There were no mortalities at the doses tested

Clinical signs:

other: Toxic signs included reduced appetite and activity for two to three days.

Gross pathology:

The viscera appeared normal by macroscopic examination.

Any other information on results incl. tables

The Acute Skin Absorption Minimal Lethal Dose of dicalcium phosphate dihydrate for rabbits

Sample applied as a 40.0% suspension in corn oil - 24 hour exposure

Animal No. – Sex	Weight Kg.	Dose mg/kg	Weight change 5 days later kg	Fate
1 – female	2.6	5010	-0.1	survived
2 – male	2.4	7940	0.0	survived
3 – female	2.6	7940	-0.1	survived

The Acute Skin Absorption Minimal Lethal Dose for male and female rabbits was found to be greater than 7940 mg/kg bw.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test material was classified, according to the author, as practically nontoxic to rabbits. The Acute Skin Absorption Minimal Lethal Dose was >7940 mg/kg bw.
This data is considered to meet the regulatory requirements for this endpoint as part of a weight of evidence approach for calcium hydrogenorthophosphate.