3,3,6,6-tetramethoxy-2,7-dioxa-3,6-disilaoctane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-06-20 until 2018-06-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

28 July 2015

GLP compliance:

yes (incl. QA statement)

Remarks:

THE DEPARTMENT OF HEALTH OF THE GOVERNMENT OF THE UNITED KINGDOM

Test material

Test material information

Constituent 1

Reference substance name:

3,3,6,6-tetramethoxy-2,7-dioxa-3,6-disilaoctane

EC Number:

242-285-6

EC Name:

3,3,6,6-tetramethoxy-2,7-dioxa-3,6-disilaoctane

Cas Number:

18406-41-2

Molecular formula:

C8H22O6Si2

IUPAC Name:

3,3,6,6-tetramethoxy-2,7-dioxa-3,6-disilaoctane

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Batch No.of test material: 611220160318
- Storage stability: 31 December 2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: refrigerator
- Stability under test conditions: guaranteed by the sponsor under storage conditions
- Solubility and stability of the test substance in the solvent/vehicle: The test item was used as supplied by the sponsor.

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- no prior treatment

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: EPISKIN Reconstructed Human Epidermis Model Kit

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiSkin from EpiSkin Laboratories, Lyon, France
- Tissue batch number: 18-EKIN-025
- Maintenance Medium lot number: 18-MAIN3-030
- Assay Medium lot number: 18-ESSC-026
- Delivery date: 19 June 2018
- Date of initiation of testing: 20 June 2018

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37°C
- Temperature of post-treatment incubation: 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: rinsing by filling and emptying each tissue insert for approximately 40 seconds using a constant soft stream of DPBS to gently remove any residual test item; transferation to maintenance medium afterwards

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL, diluted in assay medium
- Incubation time: in the dark at 37 °C, 5% CO2 in air for 3 hours
- Spectrophotometer: Labtech LT-4500 microplate reader
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Tissues Satisfactory: Yes
- Temperature Indicator Color Satisfactory: Yes
- Agar Medium Color Satisfactory: Yes

NUMBER OF REPLICATE TISSUES: 3

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

PREDICTION MODEL / DECISION CRITERIA
The prediction model is made according to OECD guideline 439 and shown in table 1.

Amount/concentration applied:

TEST MATERIAL
- Amount applied: 10 μL test item (26.3 μL/cm2) was applied

NEGATIVE CONTROL
- Amount applied: 10 µL DPBS

POSITIVE CONTROL
- Amount applied: 10 µL SDS
- Concentration: 5% (w/v)

Duration of treatment / exposure:

15 minutes at room temperature

Duration of post-treatment incubation (if applicable):

42 hours (37 °C, 5% CO2 in air)

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Remarks:

relative mean viability

Run / experiment:

mean value after 15 min exposure period and 42 h post-exposure incubation period

Value:

8.3

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Other effects / acceptance of results:

- Direct-MTT reduction:
The MTT solution containing the test item did not turn blue or purple which indicated that the test item did not directly reduce MTT.

- Colour interference with MTT:
The solution containing the test item was colorless. It was therefore unnecessary to run color correction tissues.

DEMONSTRATION OF TECHNICAL PROFICIENCY:

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control:
The mean OD570 for the negative control treated tissues was 1.114 and the standard deviation value of the viability was 4.2%.
The negative control acceptance criteria were therefore satisfied.

- Acceptance criteria met for positive control:
The relative mean tissue viability for the positive control treated tissues was 3.0% relative to the negative control treated tissues and the standard deviation value of the viability was 0.6%.
The positive control acceptance criteria were therefore satisfied.

- Acceptance criteria met for variability between replicate measurements:
The standard deviation calculated from individual tissue viabilities of the three identically test item treated tissues was 2.0%.
The test item acceptance criterion was therefore satisfied.

- Range of historical values if different from the ones specified in the test guideline:

Any other information on results incl. tables

Table 2: Results of the individual and mean OD570 values are given for the test item, negative control item and positive control item.

Item	OD570 of tissues	Mean OD570 of triplicate tissues	± SD of OD570	Relative individual tissue viability (%)	Relative mean viability (%)	± SD of Relative mean viability (%)
Negative Control Item	1.064	1.114	0.047	95.5	100*	4.2
	1.158			103.9
	1.119			100.4
Positive Control Item	0.032	0.033	0.006	2.9	3.0	0.6
	0.039			3.5
	0.027			2.4
Test Item	0.117	0.093	0.022	10.5	8.3	2.0
	0.087			7.8
	0.075			6.7

OD = Optical Density

SD = Standard deviation

∗= The mean viability of the negative control tissues is set at 100%

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

The test item was classified as irritant Cat. 2, (EC) No. 1272/2008 based on the combined knowledge with the findings in the skin corrosion testing.

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