Tetramethylcyclotetrasiloxane substituted dipropylether bisphenol A

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 2019 to September 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

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 i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

Version / remarks:

09 October 2017

Deviations:

no

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of (Tetramethylcyclotetrasiloxane propylether) prop-1-enylether bisphenol A and Di(tetramethylcyclotetrasiloxane propylether) bisphenol A

Cas Number:

203874-34-4

Molecular formula:

(OSiHxCH3)4-CH2-CH2 -CH2- O-C6H4-C(CH3)2-C6H4-0-CH2-CH2-CH2-(SiHxCH3O)4

IUPAC Name:

Reaction mass of (Tetramethylcyclotetrasiloxane propylether) prop-1-enylether bisphenol A and Di(tetramethylcyclotetrasiloxane propylether) bisphenol A

Test material form:

liquid

Details on test material:

Appearance: Pale yellow liquid

Test animals / tissue source

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Characteristics of donor animals: adult cattle (typically 12 to 60 months old)
- Storage, temperature and transport conditions of ocular tissue: The eyes were excised by an abattoir employee after slaughter, and were placed in Hanks’ Balanced Salt Solution (HBSS) supplemented with antibiotics (penicillin at 100 IU/mL and streptomycin at 100 µg/mL). They were transported to the test facility over ice packs on the same day of slaughter. The corneas were prepared immediately on arrival.
- Indication of any existing defects or lesions in ocular tissue samples: Only corneas free of damage were used.
- Indication of any antibiotics used: penicillin at 100 IU/mL and streptomycin at 100 µg/mL
- Selection and preparation of corneas: All eyes were macroscopically examined before and after dissection. Only corneas free of damage were used.
The cornea from each selected eye was removed leaving a 2 to 3 mm rim of sclera to facilitate handling. The iris and lens were peeled away from the cornea. The isolated corneas were immersed in a dish containing HBSS until they were mounted in Bovine Corneal Opacity and Permeability (BCOP) holders.
The anterior and posterior chambers of each BCOP holder were filled with complete Eagle’s Minimum Essential Medium (EMEM) without phenol red and plugged. The holders were incubated at 32 ± 1 ºC for 60 minutes. At the end of the incubation period each cornea was examined for defects. Only corneas free of damage were used.
The medium from both chambers of each holder was replaced with fresh complete EMEM.
A pre-treatment opacity reading was taken for each cornea using a calibrated opacitometer.
Three corneas were randomly allocated to the negative control. Three corneas were also allocated to the test item and three corneas to the positive control item.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

0.75 mL

Duration of treatment / exposure:

10 minutes

Duration of post- treatment incubation (in vitro):

120 minutes

Number of animals or in vitro replicates:

3

Details on study design:

APPLICATION DOSE AND EXPOSURE TIME
0.75 mL of the test item or control items were applied to the appropriate corneas. The holders were gently tilted back and forth to ensure a uniform application of the item over the entire cornea. Each holder was incubated, anterior chamber uppermost, at 32 ± 1 ºC for 10 minutes.

POST-INCUBATION PERIOD: 120 minutes.

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: After the exposure period, the cornea was rinsed 3 times with fresh complete EMEM containing phenol red before a final rinse with complete EMEM without phenol red. The anterior chamber was refilled with fresh complete EMEM without phenol red.
- POST-EXPOSURE INCUBATION: The holders were incubated, anterior chamber facing forward, at 32 ± 1ºC for 120 minutes.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: A post-treatment opacity reading was taken and each cornea was visually observed in addition to a final opacity reading after the post-incubation period.
- Corneal permeability: passage of sodium fluorescein dye measured with the aid of Labtech LT-4500 microplate reader, at 492 nm (without a reference filter)
- Histopathology :The corneas were retained after testing for possible conduct of histopathology. Each cornea was placed into a pre-labeled tissue cassette fitted with a histology sponge to protect the endothelial surface. The cassette was immersed in 10% neutral buffered formalin.

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)

DECISION CRITERIA:
The test item was classified according to the following prediction model:
IVIS UN GHS
< = 3 No Category
>3; = 55 No prediction can be made
> 55 Category 1

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Run / experiment:

mean of 3

Value:

0.4

Vehicle controls validity:

valid

Remarks:

0.0

Negative controls validity:

not applicable

Positive controls validity:

valid

Remarks:

53.7

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

The positive control In Vitro Irritancy Score was within the acceptance range. The positive control acceptance criterion was therefore satisfied.
The negative control gave opacity and permeability values below the established upper limits. The negative control acceptance criteria were therefore satisfied.
individual measurements are summarized below.

Any other information on results incl. tables

Individual and Mean Corneal Opacity and Permeability Measurements

Treatment	Cornea Number	Opacity					Permeability (OD492)		In Vitro Irritancy Score
		Pre-Treatment	Post-Treatment	Post Incubation	Post-Incubation - Pre-Treatment	Corrected Value		Corrected Value
Negative Control	2	4	4	4	0	-	0.001	-	-
	3	3	3	3	0	-	0.003	-	-
	6	6	5	5	0	-	0.003	-	-
	-	-	-	-	0.0*	-	0.002♦	-	0.0
Positive Control	9	5	34	33	28	28.0	2.165	2.163	-
	11	5	26	29	24	24.0	1.645	1.643	-
	12	3	28	29	26	26.0	1.745	1.743	-
	-	-	-	-	-	26.0•	-	1.849•	53.7
Test item	14	3	4	4	1	1.0	0.006	0.004	-
	15	4	4	4	0	0.0	0.003	0.001	-
	16	3	3	3	0	0.0	0.012	0.010	-
	-	-	-	-	-	0.3•	-	0.005•	0.4

OD = Optical density , * = Mean of the post-incubation − pre-treatment values , ♦ = Mean permeability , • = Mean corrected value

Table 2: Corneal Epithelium Condition Post Treatment and Post Incubation

Treatment	Cornea Number	Observation
		Post Treatment	Post Incubation
Negative Control	2	Clear	Clear
	3	Clear	Clear
	6	Clear	Clear
Positive Control	9	Cloudy	Cloudy
	11	Cloudy	Cloudy
	12	Cloudy	Cloudy
Test item	14	Clear	Clear
	15	Clear	Clear
	16	Clear	Clear

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

According to the experiment results, the test item is not irritant for eyes.

Executive summary:

An ex vivo eye irritation test was performed according to OECD/EC guidelines and under GLP principles. Isolated bovine corneas were treated with the negative control, positive control and test item (0.75 mL each) for exposure period 10 minutes followed by an incubation period of 120 minutes. Negative and positive control items were tested concurrently. The two endpoints, decreased light transmission through the cornea (opacity) and increased passage of sodium fluorescein dye through the cornea (permeability) were combined in an empirically derived formula to generate an In Vitro Irritancy Score (IVIS). The In Vitro Irritancy Scores were 0.0, 53.7 and 0.4 for the vehicle control, the positive control and for the test item, respectively. The criteria required for acceptance of results in the test were satisfied.
This data indicates that the test item does not have eye irritation properties.