reaction mass of neodymium carbonate and praseodymium carbonate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Study period:

08-APR-2010 to 08-MAY-2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was performed in compliance with generally acceptable scientific principles. However, no data on the guideline used was available, the study was awarded a reliability score of 2 in accordance with the Klimisch cotation criteria (1997).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

The purpose of the study was to determine the eye irritation potential of the test material using the SkinEthic reconstructed Human Corneal Epithelium model (HCE, SkinEthic Laboratories, Lyon, France) after a treatment period of 10 minutes. The test is based on the hypothesis that irritant chemicals are able to penetrate the corneal epithelial tissue and are sufficiently cytotoxic to cause cell death. The MTT assay, a colourimetric method of determining cell viability, is based on reduction of MTT to a blue formazan dye by mitochondrial succinate dehydrogenase in viable cells.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dineodymium tricarbonate

EC Number:

227-579-4

EC Name:

Dineodymium tricarbonate

Cas Number:

5895-46-5

Molecular formula:

CH2O3.2/3Nd

IUPAC Name:

dineodymium tricarbonate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Test animals / tissue source

Species:

human

Strain:

other: skinEthic reconstituted corneal model which consists of transformed human keratinocytes of the cell line HCE that form a corneal epithelial tissue

Details on test animals or tissues and environmental conditions:

The SkinEthic RHC model consists of transformed human keratinocytes of the cell line HCE (LSU EYE Center, New Orleans, USA) that form a corneal epithelial tissue (mucosa), devoid of stratum corneum, resembling, histologically, the mucosa of the human eye. The test material is applied directly to the culture surface, at the air interface, so that undiluted and/or end use dilutions can be tested directly. The model consists of an airlifted, living, corneal tissue construct, produced in polycarbonate inserts in serum free and chemically defined medium.
The test is based on the hypothesis that irritant chemicals are able to penetrate the stratum corneum of the SkinEthic RHC model and are sufficiently cytotoxic to cause cell death in the underlying cell layers.
Cytotoxicity was determined by the reduction of MTT to formazan by viable cells in the test material treated tissues (quantitative measurement of tissue viability) relative to the negative control.
One tissue for each treatment group was retained for possible tissue histopathology.
SkinEthic HCE model supplied by SkinEthic Laboratories, Nice, France; received 27 Apr 2010

Test system

Vehicle:

other: The positive control material, Sodium Dodecyl Sulphate (SDS), was prepared as a 1% w/v solution in sterile distilled water.

Controls:

other: The positive control material, Sodium Dodecyl Sulphate (SDS), was prepared as a 1% w/v solution in sterile distilled water. Negative control consisted of Na2HPO4 0.142 g/L, Glucose 1.802 g/L, HEPES 7.149 g/L, KCl 0.224 g/L, NaCl 7.597 g/L

Amount / concentration applied:

30 mg of test material
30 µL of negative control solution
30 µL 1% SDS positive controls
300 µL of 0.5 mg/mL MTT in maintenance medium

Duration of treatment / exposure:

10 min

Observation period (in vivo):

After 10 min treatment, tissues were rinsed and then loaded with fresh MTT solution for 3 h at 37 deg C, 5% CO2 in air.

Number of animals or in vitro replicates:

Triplicate tissues

Details on study design:

The experimental design of the study consists of a test for direct reduction of MTT (3 [4,5 dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) by the test material followed by the main test.
For the main test, triplicate SkinEthic tissues were treated with 30 mg of the test material for 10 minutes. Triplicate tissues treated with 30 µl of Solution A served as the negative control and triplicate tissues treated with 30 µl of 1% w/v Sodium Dodecyl Sulphate served as the positive control.
At the end of the exposure period each SkinEthic tissue was rinsed. The rinsed tissues (two per group) were taken for MTT loading. The remaining tissues were retained for possible histopathology. Following MTT loading the reduced MTT was extracted from the tissues.
After extraction the absorbency of triplicate aliquots of the extracted MTT solution for each SkinEthic tissue was measured. The optical density was measured at 540 nm (OD540). Data are presented in the form of percentage viability (MTT conversion relative to negative controls).
The test material was classified according to the following criteria:
i) If the percentage relative mean tissue viability was ≥60% the test material was considered to be non irritant (NI).
ii) If the percentage relative mean tissue viability was <60% the test material was considered to be an irritant (I).

Results and discussion

In vivo

Irritant / corrosive response data:

The relative mean viability of the test material treated tissues affter a 10 minute exposure was 105.2%; it was unecessary to proceed with tissue histopathology. According to the protocol, the test material was considered to be a non-irritant.

Any other information on results incl. tables

Table 1: Assessment of Eye Irritation Potential – Viability of RHC Tissues

 

Material	Mean Tissue Viability	Mean OD540	Viability (%)
Negative Control	0.833	0.890	100*
	0.946
Positive Control	0.356	0.368	41.3
	0.379
Test Material	0.936	0.937	105.2
	0.937

* = The mean viability of the negative control tissues is set at 100%

 

 

Table 2: Qualitative Evaluation of Tissue Viability (MTT uptake visual evaluation)

 

Material	Score
	Tissue 1	Tissue 2
Negative Control	-	-
Positive Control	+	+
Test Material	-	-

MTT Visual Scoring Scheme of SkinEthic Tissues

- = Blue tissue (viable)

+  = Blue/White tissue (semi viable)

++  = Tissue completely white (dead)

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: other: in vitro viability

Conclusions:

Based on relative mean tissue viability, the test material was considered to be non-irritant to the eyes.

Executive summary:

The purpose of this study was to determine the eye irritation potential of the test material, neodymium carbonate, using the SkinEthic Reconstituted Human Corneal model (HCE, SkinEthic Laboratories) after a treatment period of 10 minutes. 

 

The test is based on the hypothesis that irritant chemicals are able to penetrate the corneal epithelial tissue and are sufficiently cytotoxic to cause cell death.

 

The relative mean viability of the test material treated tissues after a 10 minute exposure was 105.2%, well above the criteria set to be considered an irritant (relative mean tissue viability was ≥ 60%).

 

Thus, according to the protocol followed the test material neodymium carbonate was considered to be non-irritant to the eyes. It was considered unnecessary to proceed with tissue histopathology.