4,4'-methylenebis[2,6-diethylaniline]

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October - December 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 438 (Isolated Chicken Eye Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU method B.48 (Isolated chicken eye test method for identifying occular corrosives and severe irritants)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4,4'-methylenebis[2,6-diethylaniline]

EC Number:

237-185-4

EC Name:

4,4'-methylenebis[2,6-diethylaniline]

Cas Number:

13680-35-8

Molecular formula:

C21H30N2

IUPAC Name:

4,4'-methylenebis(2,6-diethylaniline)

Test material form:

solid: crystalline

Details on test material:

- Physical state: see above
- Appearance: see above

Specific details on test material used for the study:

TEST MATERIAL
- Substance identification/name in the report: LZ 596
- Molecular formula: C21H30N2
- Batch no.: 1229
- Analysis date: August 12, 2014
- Date of production: August 11, 2014

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage conditions: Controlled room temperature (15-25ºC, <70 RH%), protected from light and humidity.
- Stability under test conditions: stable for min. 3 years from manufacturing date
- Expiry date: August 10, 2017
- Safety precautions: Routine safety precautions (lab coat, gloves, safety glasses, face mask) for unknown materials were applied to assure personnel health and safety.

Test animals / tissue source

Species:

chicken

Strain:

other: ROSS 308

Details on test animals or tissues and environmental conditions:

CHICKEN HEADS COLLECTION & TRANSPORT
- Source: Chicken heads from TARAVIS KFT. 9600 Sárvár, Rábasömjéni út 129. Hungary
- Preparation: Head collection was performed by a slaughter house technician. Heads were removed immediately after sedation of the chickens (sedation was happened by electric current). The heads were transported to the test lab at the earliest convenience for use approximately within 2 hours from collection. The ambient temperature was optimal (19.3 ºC to 20.7ºC) during the transport. All eyes used in the assay were from the same groups of eyes collected on one specific day. After collection, the heads were inspected for appropriate quality and wrapped with paper moistened with saline, then placed in a plastic box that can be closed (4-5 heads/box).

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

0.03 g test item

Duration of treatment / exposure:

10 seconds

Duration of post- treatment incubation (in vitro):

The test item was stuck on the corneas surface in three eyes at 30 minutes after the post-treatment rinse.

Number of animals or in vitro replicates:

3 eyes treated with thest item

Details on study design:

SELECTION AND PREPARATION OF ISOLATED EYES

EYES COLLECTION:
After removing the head from the plastic box, it was put on soft paper. The eyelids were carefully cut away with scissors, avoiding damaging the cornea. One small drop of fluorescein solution 2 (w/v) % was applied onto the cornea surface for a few seconds and subsequently rinsed off with 20 mL isotonic saline. Then the fluorescein-treated cornea was examined with hand-held slit lamp or slit lamp microscope, with the eye in the head, to ensure that the cornea was not damaged. If the cornea was in good condition, the eyeball was carefully removed from the orbit.

PREPARATION OF EYES:
The eye ball was carefully removed from the orbit by holding the nictitating membrane with a surgical forceps, while cutting the eye muscles with bent scissors. Care was taken to remove the eyeball from the orbit without cutting off the optical nerve too short. The procedure avoided pressure on the eye while removing the eyeball from the orbit, in order to prevent distortion of the cornea and subsequent corneal opacity. Once removed from the orbit, the eye was placed onto damp paper and the nictitating membrane was cut away with other connective tissue. The prepared eyes were kept on the wet papers in a closed box so that the appropriate humidity was maintained.

EYES EXAMINATION & ACCLIMATIZATION TIME:
The prepared eye was placed in a steel clamp with the cornea positioned vertically with the eye in the correct relative position (same position as in the chicken head). Again avoiding too much pressure on the eye by the clamp. Because of the relatively firm sclera of the chicken eyeball, only slight pressure was applied to fix the eye properly. The clamp with the eyeball was transferred to a chamber of the superfusion apparatus. The clamp holding the eye was positioned in such a way that the entire cornea was supplied with saline solution dripping from a stainless steel tube, at a rate of approximately 3 to 5 drops/minutes. The door of the chamber was closed except for manipulations and examinations, to maintain temperature and humidity.
The appropriate number of eyes was selected and after being placed in the superfusion apparatus, the selected eyes were examined again with the slit lamp microscope to ensure that they were in good condition. The focus was adjusted to see clearly the isotonic saline which was flowing on the cornea surface. Eyes with a high baseline fluorescein staining (i.e., > 0.5) or corneal opacity score (i.e., > 0.5) were rejected. The cornea thickness was measured using the depth measuring device on the slit lamp microscope (Haag-Streit BQ 900) with the slit-width set at 9½, equalling 0.095 nm. Any eye with cornea thickness deviating more than 10 % from the mean value for all eyes, or eyes that showed any other signs of damage, were rejected and replaced. If the selected eyes were appropriate for the test, acclimatization started and was conducted for approximately 45 to 60 minutes. The temperature was verified to be in the range of 32 ± 1.5 °C in all chambers during the acclimatization and treatment periods

EQUILIBRATION AND BASELINE RECORDINGS
At the end of the acclimatization period, a zero reference measurement was recorded for cornea thickness and opacity to serve as a baseline (t=0) for each individual eye. The cornea thickness of the eyes should not change by more than ±5-7 % within approximately 45 to 60 minutes before the start of application. Slight changes in thickness (0% to 2%) were observed in the eyes, finding considered as normal when maintaining enucleated eyes. Following the equilibration period, the fluorescein retention was measured. Baseline values were required to evaluate any potential test item related effects after treatment. The location of any minor findings was marked on the record sheet as a drawing, if applicable. If any eye was considered to be unsuitable following baseline assessment, it was discarded.
OF TEST SUBSTANCE
The test item was stuck on the corneas surface in three eyes at 30 minutes after the post-treatment rinse. The gentle rinsing with 20 mL saline was performed in all test item treated eyes after the 30, 75 and 120 minutes of observation. The rinsing was continued only one eye after 180 minutes of observation. The cornea surfaces were totally cleared two eyes out of three at 120 minutes after the post-treatment rinse. However, one out of three test item treated eyes was not totally cleared, little volume of test item was stuck on the cornea surface at 240 min after the post-treatment rinse.

Results and discussion

In vitro

Results

Results 1

Irritation parameter:

percent corneal swelling

Run / experiment:

1

Value:

0 - 2

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

cornea opacity score

Run / experiment:

2

Value:

0.5

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 3

Irritation parameter:

fluorescein retention score

Run / experiment:

3

Value:

0

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

In this in vitro eye irritation study using the isolated chicken eyes test with LZ 596, no ocular corrosion or severe irritation potential was observed. The test item was not a severe irritant.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item did not cause ocular corrosion or severe irritation in the enucleated chicken eyes.

Executive summary:

The purpose of this Isolated Chicken Eye Test (ICET) was to evaluate the potential ocular corrosivity or severe irritancy of the test item by its ability to induce toxicity in enucleated chicken eyes. Each eye which was used in this study was collected in the slaughterhouse, eliminating the need for laboratory animals. The test compound was applied in a single dose onto the cornea of isolated chicken eyes in order to potentially classify the test compound as ocular corrosive and/or severe irritant. The damage by the test substance was assessed by determination of corneal swelling, opacity, fluorescein retention, and morphological effects. These parameters were evaluated pre-treatment and starting at approximately 30, 75, 120, 180, and 240 minutes after the post-treatment rinse. The endpoints evaluated were corneal opacity, swelling, fluorescein retention, and morphological effects. All of the endpoints, with the exception of fluorescein retention (which was determined only at pre-treatment and 30 minutes after test substance exposure) were determined at each of the above time points. The test item and Imidazole (positive control) were applied in an amount of 0.03 g/eye by powdering the entire surface of the cornea attempting to cover the cornea surface uniformly with the test substance or positive control. Three test item treated eyes and three positive control eyes were used in this study. One negative control eye was treated with 30 μL saline solution. After an exposure period of 10 seconds from the end of the application the cornea surface was rinsed thoroughly with ~20 mL saline solution at ambient temperature and this procedure was repeated for each eye. In this ICET, The test item did not cause ocular corrosion or severe irritation in the enucleated chicken eyes. Positive and negative controls showed the expected results. The experiment was considered to be valid. In this in vitro eye corrosives and severe irritants study, using the Isolated Chicken Eye model with LZ 596, no ocular corrosion or severe irritation potential was observed.