Tris(trimethylsilyl) phosphate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

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)

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)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Tris(trimethylsilyl) phosphate

EC Number:

234-028-1

EC Name:

Tris(trimethylsilyl) phosphate

Cas Number:

10497-05-9

Molecular formula:

C9H27O4PSi3

IUPAC Name:

tritrimethylsilyl phosphate

Specific details on test material used for the study:

Name Tris(trimethylsilyl) Phosphate
Batch no. DV1105A19028
Appearance clear, colourless liquid
Composition Tris(trimethylsilyl) Phosphate
Purity 99.60%
Homogeneity homogeneous
Storage Room temperature (20 ± 5 °C); keep under inert gas

Test animals / tissue source

Species:

cattle

Strain:

other: Bos primigenius Taurus

Details on test animals or tissues and environmental conditions:

Fresh bovine eyes were obtained from the slaughterhouse Müller Fleisch GmbH, Enzstr. 2-4, 75217 Birkenfeld, Germany, on the day of the test. The cattle were between 12 and 60 months old.

Test system

Controls:

yes

Amount / concentration applied:

The eyes were transported to the test facility in Hanks’ Balanced Salt Solution with 1% Penicillin-Streptomycin solution (Penicillin 100 U/mL, Streptomycin 100 µg/mL) in a suitable cooled container.

Duration of treatment / exposure:

within 1 hour and 15 minutes

Duration of post- treatment incubation (in vitro):

10 min

Details on study design:

Method Description
After the initial incubation, the medium was completely changed and the baseline opacity for each cornea was recorded. None of the corneas showed tissue damage; therefore, all corneas were used. For each treatment group (negative control solution, test item or positive control), three replicates were used. After removal of the pre-incubation medium (cMEM without phenol red), 750 µL negative control solution, 750 µL test item or 750 µL positive control solution were applied to each replicate to the epithelial side of the cornea.
According to the characteristics of the test item, the following treatment procedure was performed.

Closed Chamber Method
The respective substance (negative control solution, test item or positive control) was applied by pipetting 750 µL of the appropriate liquid through the refill hole in the anterior holder on the cornea. The controls and the test item were given on the epithelium that the cornea was evenly covered.
Exposure time of the controls and test item on the corneas was 10 minutes at 32 ± 1 °C. After thorough rinsing the anterior chambers with cMEM with phenol red and final rinsing with cMEM without phenol red, the anterior chambers were filled with cMEM without phenol red and the cornea holders were stored for additional 2 hours at 32 ± 1 °C (post-incubation).
After post-incubation time, the cMEM without phenol red was renewed in both chambers of each cornea holder. Then, the final opacity value of each cornea was recorded.

Permeability Test
After the recording of the final opacity values, the cMEM without phenol red was removed from both chambers of each cornea holder. The posterior chamber, which interfaces with the endothelial side of the cornea was filled with fresh cMEM. Then 1 mL sodium fluorescein solution was added to the front chamber of each cornea holder for the detection of permeability of the corneas.
For liquid test items, a sodium fluorescein solution with a concentration of 4 mg/mL was used.
The chambers were then closed again and incubated for 90 minutes at 32 ± 1 °C in a horizontal position. After incubation, the content of each posterior chamber was thoroughly mixed and pipetted in a 96-well plate. Then, its optical density at 492 nm was measured with the microtiter plate photometer.
 

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Value:

ca. 94

Any other information on results incl. tables

Test Group	IVIS	Mean IVIS	Relative Standard Deviation IVIS
Negative Control HBSS	0.03	0.11	132.87%*
	0.03
	0.28
Test Item Tris(trimethylsilyl) Phosphate	102.78	94.00	8.16%
	88.57
	90.66
Positive Control DMF undiluted	127.07	120.58	8.30%
	125.61
	109.05

Note: the high relative standard deviation of the IVIS of the negative control is due to mathematical reasons, as the respective means are very small.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

This in vitro study was performed to assess corneal damage potential of Tris(trimethylsilyl) Phosphate by quantitative measurements of changes in opacity and permeability in a bovine cornea.
The test item Tris(trimethylsilyl) Phosphate was brought onto the cornea of a bovine eye which previously had been incubated with cMEM without phenol red at 32 ± 1 °C for 1 hour and whose opacity had been determined. The test item was incubated on the cornea for 10 minutes at 32 ± 1 °C. After removal of the test item and 2 hours post-incubation, opacity and permeability values were measured.

The test item was tested neat.
Under the conditions of this test, the test item Tris(trimethylsilyl) Phosphate induced serious eye damage on the cornea of the bovine eye. The calculated mean IVIS was 94.00.
According to OECD Guideline no. 437 (Oct. 2017), a substance with an IVIS > 55 induces serious eye damage, that should be classified as UN GHS Category I.
The negative control (HBSS) and the positive control (undiluted dimethylformamide) have met the validity criteria.