Dioxybenzone

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-11-06 -

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study under GLP conditions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

Version / remarks:

July 2013

GLP compliance:

yes (incl. QA statement)

Remarks:

2016-11-02

Test material

Test material information

Constituent 1

Reference substance name:

Dioxybenzone

EC Number:

205-026-8

EC Name:

Dioxybenzone

Cas Number:

131-53-3

Molecular formula:

C14H12O4

IUPAC Name:

2-(2-hydroxybenzoyl)-5-methoxyphenol

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Name: 2,2`-Dihydroxy-4-methoxybenzophenone
Synonyms: CYASORB® UV-24 Light Absorber; CYASORB UV-24
CAS No.: 131-53-3
Batch No.: CM70314A1
Description: Yellow powder
Storage condition: At room temperature
Purity: 99.8%
Expiry date: 14 March 2019

Test animals / tissue source

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

- Species: bovine cattle (Bos taurus).
- Origin: bovine eyes were obtained from freshly slaughtered cattle at the abattoir EVA, Saint Pierre sur Dives, France.
- Age: as French Authorities avoid the use of any organs from the head of bovines aged more than 12 months, bovine cattle were up to 12 months old (typically, 5 to 8 months old).
- Reason for choice: bovine corneas are recommended by Regulatory Authorities for this type of study. They are adapted for the evaluation of potential ocular irritants since they are part of the target organ.
- Transport from Supplier to Testing facility: the eyes were immerged in containers filled with cooled buffered Hanks medium and placed into a cooling-box with a sufficient amount of ice packs to ensure cooling until arrival at the testing faciligy. Containers with smooth internal surfaces were used for the transport to avoid damage to the corneas. Hank’s medium contained an antibiotic [Hank’s Balanced Salts Solution (HBSS) plus penicillin/streptomycin (100 units/100 µg/mL final)].

Test system

Vehicle:

other: Paraffin oil

Controls:

yes, concurrent vehicle

yes, concurrent positive control

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 750 µl per cornea
- Concentration: 20% w/v in Paraffin oil

VEHICLE CONTROL
- Amount applied: 750 µl

POSITIVE CONTROL
- Amount applied: 750 µl
- Concentration: 20% w/v imidazole solution in 0.9% NaCl

Duration of treatment / exposure:

4 h

Number of animals or in vitro replicates:

3

Details on study design:

SELECTION AND PREPARATION OF CORNEAS
- Selection: a careful macroscopic examination was performed on all eyes to detect the presence of any defects (opacity, scratches, pigmentation, etc). Any eyes with defects were discarded. The examination was performed under a lamp, using HBSS in order to keep the eyes moistened and shiny. Particular attention was paid to the corneas and the eyes were swiveled in order to observe the fringe areas and any scratches directly under the light.
- Preparation of the selected corneas: the tissues surrounding the eyeball were carefully pulled away and the cornea, surrounded by approximately 2 to 3 mm of sclera, was dissected out. The isolated corneas were stored in HBSS until all corneas had been prepared. The corneas were used immediately.

NUMBER OF REPLICATES
3

NEGATIVE CONTROL USED
None, replaced by solvent control

SOLVENT CONTROL USED
Vehicle control: Paraffin oil

POSITIVE CONTROL USED
20% imidazole solution in 0.9% NaCl (w/v)

APPLICATION DOSE AND EXPOSURE TIME
750 µL for 4 hours

TREATMENT METHOD: open chamber for the test item / closed chamber for the positive and negative controls

POST-INCUBATION PERIOD: no

REMOVAL OF TEST SUBSTANCE
On completion of the treatment period, the test item formulation was removed from the front opening of the anterior chamber (open-chamber method) and the epithelium was rinsed as follows:
- any residual amounts of the test item formulation, adhering to the walls of the anterior chamber, was removed first with a cotton bud and then using a pipette of heated cMEM (32°C),
- the corneas were rinsed four times with pre-warmed cMEM containing phenol red (i.e. until the test item formulation had been completely removed from the chamber or until the phenol red was not discoloured). Then, the corneas were finally rinsed with pre-warmed cMEM without phenol red.
The rinsing efficiency was visually confirmed by observing the transparency and the colour changing of the rinsing medium (containing phenol red). After the rinsing step, the residual amounts of test item formulation, previously observed on the walls of the anterior chamber, were no more noted.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: OPKIT opacitometer and calibrators
- Corneal permeability: passage of sodium fluorescein dye measured with the aid of UV/VIS spectrophotometry (OD490)

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)

DECISION CRITERIA:
IVIS =< 3: No category in UN GHS
IVIS >3 -=< 55: No prediction can be made
IVIS > 55: Category 1 in UN GHS

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean of 3 corneas

Value:

1

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Other effects / acceptance of results:

All acceptance criteria were fulfilled. The study was therefore considered as valid.
IVIS of positive control: 159 (mean of 3 corneas)

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the experimental conditions of this study, the test item, 2,2`-Dihydroxy-4-methoxybenzophenone, was identified as not requiring classification for eye irritation or serious eye damage (UN GHS No Category).

Executive summary:

2,2'-Dihydroxy-4 -methoxybenzophenone was screened for the eye irritancy potential using the BCOP test performed according to OECD 437 guideline and GLP principles.

The substance did not induce ocular irritation through both endpoints, opacity and permeability, resulting in a mean in vitro irritancy score of 1.0 after 4 hours of treatment.

Based on the results it is concluded that 2,2'-Dihydroxy-4 -methoxybenzophenone is not a severe irritant or corrosive in the Bovine Corneal Opacity and Permeability test.

Acceptability test and interpretation results: The BCOP test method is recommended by authorities to identify the eye hazard potential of a test chemical. This test method is also recommended to identify chemicals that do not require classification for eye irritation or serious eye damage, as defined by the UN GHS, in case IVIS =< 3. As in the present study an IVIS of 1.0 was obtained, indicating no irritating properties, further testing for eye irritating properties is considered redundant and ethically not justified.