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Toxicological information

Eye irritation

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Administrative data

Endpoint:
eye irritation
Remarks:
other: in vitro MTT test
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
2013, March
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study, well conducted on the similar substance Reaction mass of dipotassium phosphonate and Phosphonic acid, potassium salt (1:1). Rationale for Read Across is attached at point 13

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: MTT test method
Deviations:
no
Principles of method if other than guideline:
The method allows to evaluate a toxic event and related cytotoxicity by a colorimetric assay. Solution of MTT in balanced saline is yellowish in color. Mitochondrial dehydrogenase of viable cells cleaves the tetrazolium ring yielding blue/purple MTT crystals which are insoluble in aqueous solutions. Crystals formed by viable cells are retained in the polycarbonate filter used as substrate for the 3D construct. Intense purple colour of the cultures indicates the viability of the cell at the basal layer, whereas colour remains white when necrosis occurs. Negative controls are of a dark blue colour and positive controls are white-yellow.
MTT crystals are extracted by isopropanol and optical density is measured at 570 nm.
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous
Details on test material:
- Name of test material: potassium phosphonate KH2PO3/K2HPO3
- Substance type: inorganic
- Physical state: clear free-flowing white/colourless solution
- Storage condition of test material: ambient condition
- Stability: no assay of test item stability, nor its concentration and homogeneity in solvent were undertaken
- Expiration date of the lot/batch: 16/12/2013
- Preparation: the test item was used in the form supplied, without any further dilution. No analysis was carried out.

Test animals / tissue source

Species:
other: HCE corneal epithelium model
Strain:
not specified
Details on test animals or tissues and environmental conditions:
TEST SYSTEM
- Source:SKINETHIC LABORATORIES

Test system

Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
TEST MATERIAL

- Concentration (if solution):The test item was tested at the dose defined for liquid (30 µL).

Duration of treatment / exposure:
1 hour
Observation period (in vivo):
not required
Number of animals or in vitro replicates:
no aminals required
Details on study design:
The test was performed on triplicate tissues for MTT and in simplicate for histological analysis.
The positive control was Ethanol (99,96%) and as negative control saline solution (NaCl 0,9%) was used. 30 µL of controls (liquids) were directly and uniformly applied topically.

SCORING SYSTEM:cell viability

OTHER: the test was performed in triplicate

Results and discussion

In vivo

Results
Irritation parameter:
other: Cell viability
Basis:
mean
Time point:
other: 1h + 16h
Score:
ca. 47
Max. score:
100
Reversibility:
not specified
Remarks on result:
other: SD ± 0.039
Irritant / corrosive response data:
The prediction model for eye irritation ciassification is based on cell viability (MTT-modified protocol) after 1h+16h exposure (SOP M 04).
A cut-off of 50% is accepted for discriminating between potential irritant (<50 %) and not classified (>50 %). Positive control (Ethanol) satisfies acceptance criteria if it is classified as irritant (<50 %).
Mean tissue viability is <50 % Irritant (I) R36
Mean tissue viability is >50 % Not Classified (NC)

Applicant's summary and conclusion

Interpretation of results:
slightly irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
A cell viability > 50% corresponding to the cut-off value for eye irritant classification has been quantified for the test item (0,47%).
Executive summary:

The present study has been conducted in order to assess in vitro, on a Human Corneal Epithelium model (HCE), the eye irritation potential of Potassium Phosphonate KH2PO3/K2HPO3

Eye irritation potential of the test item was assessed at 1h followed by product washing and a post incubation period of 16h by using the MTT test method to quantify the residual cell viability. A complementary histo-morphological analysis was associated.

According to the adopted prediction model based on MTT results the chemicals have been classified as reported in the following table.

Classification based on cell viability-MTT results.

CHEMICAL 1h+16h
KH2PO3 IR
ETOH IR
  IR

(NC=Not Classified; IR=Irritant for the eye, R 36 )

The scoring of the complementary histo-morphological analysis was in agreement with the cell viability results.

A cell viability < 50% corresponding to the cut-off value for eye irritant classification has been quantified for the test item (0,47%).