Tetrakis(2-ethylbutyl) orthosilicate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 Aug 2017 - 31 Aug 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

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:

26 July 2013

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Tetrakis(2-ethylbutyl) orthosilicate

EC Number:

201-085-9

EC Name:

Tetrakis(2-ethylbutyl) orthosilicate

Cas Number:

78-13-7

Molecular formula:

C24H52O4Si

IUPAC Name:

tetrakis(2-ethylbutyl) orthosilicate

Test material form:

liquid

Details on test material:

Tetrakis(2-ethylbutyl) Orthosilicate
CAS 78-13-7
Expiration: May 2020
Clear colorless liquid

Specific details on test material used for the study:

Tetrakis(2-ethylbutyl) Orthosilicate CAS 78-13-7 Lot# 8E-33-134

Test animals / tissue source

Species:

other: Isolated Bovine Cornea

Strain:

other: not applicable

Details on test animals or tissues and environmental conditions:

The bovine eyes, in a Hanks’ Balance Salt Solution (HBSS) with penicillin-streptomycin, were received from Spear Products on 31 Aug 2017 and transported to MB Research in a refrigerated container.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

0.75 ml of the test article

Duration of treatment / exposure:

10 (±1) minutes at 32 (±1)°C

Observation period (in vivo):

N/A

Duration of post- treatment incubation (in vitro):

All corneas were incubated at 32 (±1)°C for an additional two hours at which time the MEM solution in the anterior and posterior chambers was removed and the holders refilled with fresh MEM solution.

Number of animals or in vitro replicates:

3 bovine corneas per group

Details on study design:

Application/Treatment of test article:
Following the pretest observations, the MEM solution was removed from the anterior chamber. A volume of 0.75 ml of test article, ethanol or MEM solution was applied to the epithelium of each of the three test article corneas, three positive control corneas and three negative control corneas and three vehicle control corneas in a manner which ensured that the entire cornea was covered. All corneas were dosed via the closed-chamber method. All holders and corneas were placed in a horizontal position (anterior side up) in the 32 (±1)°C incubator. After 10 (±1) minutes), the test article, ethanol or MEM was removed from the epithelium of the cornea and anterior chamber of the holder by washing with MEM solution containing phenol red. A final rinse was made with MEM without phenol red. The anterior and posterior chambers of the holders were then refilled with fresh MEM solution. Opacity measurements were made following the 10-minute exposure and MEM solution refill. All corneas were incubated at 32 (±1)°C for an additional two hours at which time the MEM solution in the anterior and posterior chambers was removed and the holders refilled with fresh MEM solution.

Opacity Measurement:
A measurement of opacity was taken with each treated cornea compared to the blank supplied with the OP-KIT. This reading was used in the final IVIS calculations. Immediately following the two-hour opacity measurement, the MEM solution was removed from the anterior chamber and replaced with 1.0 ml of 0.4% sodium fluorescein solution in Dulbecco's phosphatebuffered saline (PBS). Each holder was then returned to the 32 (±1)°C incubator in a horizontal position (anterior side up) ensuring contact of the fluorescein with the cornea. After 90 (±5) minutes, the fluid from the posterior chamber was removed and the amount of dye that passed through the cornea (permeability) was measured as the optical density at 490 nm by a spectrophotometer. A 1:1000 dilution of the fluorescein was prepared and measured in the spectrophotometer as a measure of consistency.

Results and discussion

In vitro

Results

Results 1

Irritation parameter:

cornea opacity score

Remarks:

2-hour corrected

Value:

-1.33

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

in vitro irritation score

Run / experiment:

In vitro irritation score (IVIS) calculated from opacity score

Value:

-1.24

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

The ethanol positive control IVIS was 29.95, which fell within the acceptance range of 16.96 – 37.00 (± 2 standard deviations of the historical mean).

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The mean corneal opacity, and in-vitro irritation score for Tetrakis(2-ethylbutyl) Orthosilicate were -1.33 and -1.24, respectively. These findings do not warrant classification of Tetrakis(2-ethylbutyl) Orthosilicate as a substance inducing serious eye damage (Category 1) under the Regulation (EC) 1272/2008 on classification, labelling and packaging of substances and mixtures (CLP).

Executive summary:

Tetrakis(2-ethylbutyl) Orthosilicate (neat) was applied to isolated bovine cornea to assess for the potential to induce serious eye damage. Ocular damage was assessed at 4 hours post-instillation and scored through measurement of corneal opacity and permeability. The mean corneal opacity, and in-vitro irritation score for Tetrakis(2-ethylbutyl) Orthosilicate were -1.33 and -1.24, respectively. These findings do not warrant classification of Tetrakis(2-ethylbutyl) Orthosilicate as a substance inducing serious eye damage (Category 1) under the Regulation (EC) 1272/2008 on classification, labelling and packaging of substances and mixtures (CLP).