Hydroxylapatite (Ca5(OH)(PO4)3)

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 26.Oct. 2015 to 29.Jan. 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)

Version / remarks:

EpiOcular(TM) kit

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

certified by Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Kaiser-Friedrich-Str. 7, D-55116 Mainz, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Hydroxylapatite (Ca5(OH)(PO4)3)

EC Number:

215-145-7

EC Name:

Hydroxylapatite (Ca5(OH)(PO4)3)

Cas Number:

1306-06-5

Molecular formula:

Ca5HO13P3

IUPAC Name:

pentacalcium hydroxide triphosphate

Test material form:

solid: particulate/powder

Test animals / tissue source

Species:

human

Strain:

not specified

Details on test animals or tissues and environmental conditions:

Commercially available EpiOcular(TM) kit (OCL-212-EIT, batch no. 21580), procured by MatTek In Vitro Life Science Laboratories, Mylnské Nivy 73, 82105 Bratislava, Slovakia.
The EpiOcular(TM) tissue consist of normal, human-derived keratinocytes cultured to form a stratified epithelium similar to the human cornea. These cells are not transformed or transfected with genes to induce an extenden life span. The tissues are cultured in specially prepared cell culture inserts with a porous membrane through which nutrients can pass. The surface is 0.6cm².

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

Tissue 1: 49.4 mg/plate
Tissue 2: 46.0 mg/plate

Duration of treatment / exposure:

6 hours

Duration of post- treatment incubation (in vitro):

18h at 37+/-1°C, 5+/-1% CO2 and 80-100% relative humidity

Number of animals or in vitro replicates:

2 x 2

Details on study design:

In a pre-Test no direct reduction of MTT by the test substance or change of colour by test substance or medium was found. Before use all cell cultures were inspected for viability and the presence of air bubbles between agarose gel and insert.
After overnight incubation, pre-wetting and a further incubation for 30 minutes, the test substance and controls (50µl) were applied. The exposure time was controlled by a stop watch. The tissues were removed, rinsed immediately and transfered to new medium for pre-incubation. Then the tissues were incubated in freshly prepared MTT-reagent for 180 minutes. The living cells reduce MTT to a formazan salt, that is extracted by isopropanol and quatified by a plate spectral photometer at 570nm. Then the viability of the cells is calculated.

Results and discussion

In vitro

Results

Irritation parameter:

other: viability (%) by absorbance values

Run / experiment:

tissue 1: 97.7% viability, tissue 2: 100.1% viability, mean: 98.9% viability

Value:

1.566

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The threshold for eye irritation potential in this test is