Pentacalcium hydroxide tris(orthophosphate)

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The test site area was larger at 2"x2" than the recommened 1"x1".

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

May 12, 1981

Deviations:

yes

Remarks:

minor deviations as test site larger than recommended; for more detail see "Further information on Material and Methods"

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: U.S. E.P.A. Pesticide Assessment Guidelines; Subdivision F, Hazard Evaluation: Human and Domestic Animals, November 1984; 81-5 Primary Dermal Irritation Study.

Deviations:

not specified

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: Commission of the European Communities, Council Directive 67/548/EEC, Annex V, Part B.4; May 1, 1987,

Deviations:

not specified

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: FMC Primary Skin Irritation Protocol (Number 16)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Pentacalcium hydroxide tris(orthophosphate)

EC Number:

235-330-6

EC Name:

Pentacalcium hydroxide tris(orthophosphate)

Cas Number:

12167-74-7

Molecular formula:

Ca5HO13P3

IUPAC Name:

Calcium hydroxycalcium(1+) phosphate (4:1:3)

Constituent 2

Reference substance name:

tricalcium phosphate

IUPAC Name:

tricalcium phosphate

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: HRP, Inc., Denver, PA on May 12, 1993
- Age at study initiation: The rabbits are referred to as 'young'.
- Weight at study initiation: 2.67 - 2.85 kg
- Housing: The animals were inidividually housed in stainless steel cages. Deosorb indirect bedding was used in the litter pans.
- Diet (e.g. ad libitum): Purina High Fiber Rabbit Chow 5326 was provided
- Water (e.g. ad libitum): Fresh tap water was provided
- Acclimation period: The animals were acclimated for a minimum of 5 days prior to study start.

ENVIRONMENTAL CONDITIONS
- Temperature: 65 - 69°F (18.3 - 20.6°C)
- Humidity (%): 45 - 66 %
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 hours fluorescent light and 12 hour dark cycle.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

other: The test material was moistened with physiological saline

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 gram

Duration of treatment / exposure:

4 h

Observation period:

72 h

Number of animals:

Six animals were used in this study, three males and three females. Per animal 2 test sites were prepared and dosed.

Details on study design:

TEST SITE
- Other: Per animal there were 2 test sites either side of the spinal column.
- Area of exposure: each site was approximately 26 square cm
- % coverage: no data
- Test material administration: The test material was weighed onto an 8-ply, 2"x2" gauze pad and moistened with physiological saline. The gauze pad was secured with hypoallergenic tape. The entire trunk of the animal was wrapped with a semi-occlusive cheesecloth bandage.

REMOVAL OF TEST SUBSTANCE
- Washing: test sites were wiped with gauze moistened with methanol and then rinsed with tap water.
- Time after start of exposure: 4 h

SCORING SYSTEM: Approximately 30 minutes after unwrapping, the test sites of each rabbit were scored for irritation using the method of:
Draize J. H., G. Woodard and H. O. Calvery, J. Pharmacol. Exp. Ther., 83, 384 (1944). The 30 minute delay was instituted to allow for regression of pressure and hydration effects.

RATING SYSTEM: The FMC rating system.
- Non Irritating: No irritation observed in any animal at any scoring interval.
- Slightly irritating: Any animal exhibiting scores of 1 or less at any scoring interval and irritation clearing within 72 hours.
- Mildly irritating: Any animal exhibiting scores of 2 or less at any scoring interval and irritationg clearing within 7 days.
- Moderately irritating: Any animal exhibiting scores of 3 or less at any scoring interval and irritation clearing within 7 days.
- Severely irritating: Any animal exhibiting scores of 4 or less at any scoring interval.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

edema score

Basis:

other: all 6 animals tested

Time point:

other: mean 24, 48 and 72 hrs

Score:

0

Max. score:

4

Results 2

Irritation parameter:

erythema score

Basis:

other: all 6 animals tested

Time point:

other: mean 24, 48 and 72 hrs

Score:

0

Max. score:

4

Irritant / corrosive response data:

No irritation was noted on any of the test sites during the study.

Other effects:

All animals remained healthy throughout the study.

Any other information on results incl. tables

Zero scores were recorded at all test sites at all time points, i.e. at 4.5, 24, 48 and 72 hours post exposure.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, the test material is judged to be non-irritating to intact skin when applied topically to New Zealand White rabbits.