Dipotassium adipate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06/2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP comparable to OECD guideline

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU method B.47 (Bovine corneal opacity and permeability test method for identifying ocular corrosives and severe irritants)

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: Background Review Document (BRD): current status of in vitro test methods for identifying ocular corrosives and severe irritants: The Bovine Corneal Opacity and Permeability (BCOP) Test Method, March 2006.

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: - In Vitro Techniques in Toxicology Database (INVITTOX) protocol 127. Bovine Opacity and Permeability (BCOP) Assay, 2006.

Test guideline 5

Qualifier:

according to guideline

Guideline:

other: - Gautheron P., Dukic M., Alix D. and Sina J.F., Bovine corneal opacity and permeability test: An in vitro assay of ocular irritancy. Fundam Appl Toxicol 18:442-449, 1992.

Principles of method if other than guideline:

/

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dipotassium adipate

EC Number:

242-838-1

EC Name:

Dipotassium adipate

Cas Number:

19147-16-1

Molecular formula:

C6H10O4.2K

IUPAC Name:

dipotassium adipate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Potassium adipate
- Physical state: white crystalline powder with lumps
- Lot/batch No.: 150413AK DRIED
- Expiration date of the lot/batch: 29/04/2014
- Stability under test conditions: not indicated
- Storage condition of test material:at room temperature in the dark

Test animals / tissue source

Species:

other: Cow

Strain:

other: not specified

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source:Bovine eyes from young cattle were obtained from the slaughterhouse (Vitelco, 's Hertogenbosch, The Netherlands

ENVIRONMENTAL CONDITIONS
- Temperature (°C): corneas were stored at 32 +/- 1°C

Test system

Vehicle:

physiological saline

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
- Concentration (if solution): 20% (w/w) in physiological saline

VEHICLE
- Amount(s) applied (volume or weight with unit): 750µL

Duration of treatment / exposure:

240 +/- 10 mintues

Observation period (in vivo):

Opacity was determined without further incubation

Number of animals or in vitro replicates:

9 corneas were tested

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): After the incubation the solutions and the test compound were removed and the epithelium was washed at least three times with MEM with phenol red (Eagle’s Minimum Essential Medium, Invitrogen Corporation).
- Time after start of exposure: 240 min

SCORING SYSTEM:
OPACITY MEASUREMENT
The opacitometer determined the difference in the light transmission between each control or treated cornea and an air filled chamber. The numerical opacity value (arbitrary unit) was displayed and recorded. The change in opacity for each individual cornea (including the negative control) was calculated by subtracting the initial opacity reading from the final post-treatment reading. The corrected opacity for each positive control or test substance treated cornea was calculated by subtracting the average change in opacity of the negative control corneas from the change in opacity of each positive control or test substance treated cornea.
The mean opacity value of each treatment group was calculated by averaging the corrected opacity values of the treated corneas for each treatment group.
APPLICATION OF SODIUM FLUORESCEIN
Following the final opacity measurement, permeability of the cornea to Na-fluorescein (Merck) was evaluated.

The medium of both compartments (anterior compartment first) was removed. The posterior compartment was refilled with fresh cMEM. The anterior compartment was filled with 1 ml of 5 mg
Na-fluorescein/ml cMEM solution. The holders were slightly rotated, with the corneas maintained in a horizontal position, to ensure uniform distribution of the sodium-fluorescein solution over the entire cornea. Corneas were incubated in a horizontal position for 90 ± 5 minutes at 32 ± 1°C.
PERMEABILITY DETERMINATION
After the incubation period, the medium in the posterior compartment of each holder was removed and placed into a sampling tube labelled according to holder number. 360 μl of the medium from each sampling tube was transferred to a 96-well plate. The optical density at 490 nm (OD490) of each sampling tube was measured in triplicate using a microplate reader (TECAN Infinite® M200 Pro Plate Reader. Any OD490 that was 1.500 or higher was diluted to bring the OD490 into the acceptable range (linearity up to OD490 of 1.500 was verified before the start of the experiment). OD490 values of less than 1.500 were used in the permeability calculation.

The mean OD490 for each treatment was calculated using cMEM corrected OD490 values. If a dilution was performed, the OD490 of each reading was corrected for the mean negative control OD490 before the dilution factor was applied to the readings.
ELECTRONIC DATA CAPTURE
Observations/measurements in the study were recorded electronically using the following programme: Magellan Tracker 7.0 (TECAN, Austria) for optical density measurement.

IN VITRO IRRITANCY SCORE
The mean opacity and mean permeability values (OD490) were used for each treatment group to calculate an in vitro score:

In vitro irritancy score (IVIS) = mean opacity value + (15 x mean OD490 value).

Additionally the opacity and permeability values were evaluated independently to determine whether the test substance induced irritation through only one of the two endpoints.

A test substance that induces an IVIS ≥ 55.1 is defined as a corrosive or severe irritant.


TOOL USED TO ASSESS SCORE: fluorescein

Results and discussion

In vitro

Results

Irritation parameter:

cornea opacity score

Value:

ca. 6.3

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Applicant's summary and conclusion

Conclusions:

It is concluded that this test is valid and that POTASSIUM ADIPATE is not severe irritant or corrosive in the Bovine Corneal Opacity and Permeability test under the experimental conditions described in this report.

Executive summary:

 

Screening for the eye irritancy potential of POTASSIUM ADIPATE using the Bovine Corneal Opacity and Permeability test (BCOP test).

 

This report describes the ocular irritation properties of POTASSIUM ADIPATE on an isolated bovine cornea. The possible ocular irritancy of POTASSIUM ADIPATE was tested through topical application for approximately 240 minutes.

 

The study procedures described in this report were based on the most recent OECD and EC guideline.

 

Batch 150413AK DRIED of POTASSIUM ADIPATE was a white crystalline powder with lumps.The test substance was applied as a 20% (w/w) solution (750 µl) directly on top of the corneas.

 

The negative control responses for opacity and permeability were less than the upper limits of the laboratory historical rangeindicating that the negative control did not induce irritancy on the corneas.The meanin vitroirritancy score of the positive control (20% (w/v) Imidazole) was 150 and within the historical positive controldata range.It was therefore concluded that the test conditions were adequate and that the test system functioned properly.

 

The meanin vitroirritancy score was 6.3 after 240 minutes of treatment with POTASSIUM ADIPATE.

Since the meanin vitroirritancy score for POTASSIUM ADIPATE was below 55.1 after 240 minutes treatment POTASSIUM ADIPATE is considered to be not severe irritant or corrosive.

 

Finally, it is concluded that this test is valid and that POTASSIUM ADIPATE is not severe irritant or corrosive in the Bovine Corneal Opacity and Permeability test under the experimental conditions described in this report.

 

As stated in the OECD 437 method and in the Guidance of Information Requirements chapter 7a (7.2.9) the BCOP in vitro test is recommended to identify substances inducing serious eye damage, i.e. substances to be classified in Eye Damage Category 1 under CLP, without further testing, and also recommended to identify substances that do not require classification for eye irritation or serious eye damage i.e. leading to non-classification under CLP, without further testing. In this case the results clearly showed that the substance is not Category 1 but also were above the non-classification threshold. Then, is realistic to classify the substance as Skin irritant category 2, according to CLP