Dibutoxy(dimethyl)silane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014-12-08 to 2014-12-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted to the appropriate OECD test guideline and in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dibutoxy(dimethyl)silane

EC Number:

216-467-0

EC Name:

Dibutoxy(dimethyl)silane

Cas Number:

1591-02-2

Molecular formula:

C10H24O2Si

IUPAC Name:

dibutoxydimethylsilane

Test material form:

other: liquid at room temperature

Details on test material:

- Name of test material (as cited in study report): Dibutoxy(dimethyl)silane
- Physical state: Liquid
- Stability under test conditions: undergoes hydrolysis in water, otherwise stable
- Storage condition of test material: at room temperature, protected from water and moisture, tightly closed and protected well from heat/ignition source

Test animals

Species:

human

Strain:

other: Not relevant

Details on test animals or test system and environmental conditions:

Not relevant

Test system

Type of coverage:

other: Not relevant

Preparation of test site:

other: Not relevant

Vehicle:

unchanged (no vehicle)

Controls:

other: Not relevant

Duration of treatment / exposure:

Not relevant

Observation period:

Not relevant

Number of animals:

Not relevant

Details on study design:

Upon receipt of the EPISKIN-SMTM, the tissues were transferred into 12-well plates containing 2 mL pre-warmed maintenance medium per well. The 12-well plates were incubated in a humidified incubator at 37 ± 1 °C, 5.0% CO2 for at least 24 h.

After this pre-incubation the tissues were treated with each dose group in triplicate, starting with the negative control. Start time was recorded with dosing of the first tissue. Then the tissues were incubated at room temperature for 15 ± 0.5 min. Afterwards, the tissues were washed with phosphate buffered saline (PBS) to remove any residual test item. Excess PBS was removed by blotting bottom with blotting paper. The inserts were placed in a prepared 12-well plate containing 2 mL pre-warmed fresh maintenance medium and post-incubated at 37 ± 1 °C, 5.0% CO2 for 42 ± 1 h.

After this incubation period the plates were placed for 15 ± 2 min. on a plate shaker. Then the inserts were transferred in a prepared 12-well plate containing 2 mL pre-warmed 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliu bromide (MTT) medium and further incubated for 3 h ± 5 min. at 37 ± 1 °C, 5.0% CO2.

After the 3 h MTT incubation period the tissues were placed on blotting paper to dry the tissues. Afterwards a total biopsy of the epidermis by using the special biopsy punch was performed and the epidermis was separated from the collagen matrix with the aid of forceps. Both parts (epidermis and collagen matrix) were transferred into suitable tubes and 500 µL of acidic isopropanol were added. Extraction was carried out protected from light over the weekend at 2 - 8°C.

At the end of the formazan extraction period the tubes were mixed by vortexing until solution colour became homogeneous.
If any visible cell/tissue fragments were in suspension, the tubes were centrifuged at 500 rpm to eliminate the fragments and avoid further possible interference with the absorbance readings.

Per each tissue 2 x 200 µL aliquots of the extract were transferred into a 96-well plate and absorbance (OD) was measured at 550 nm without reference wavelength in a plate spectrophotometer.

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

other: other: Not relevant

Remarks on result:

other:

Any other information on results incl. tables

The mixture of 10 µL test item per 2 mL MTT medium showed no reduction of MTT compared to the solvent. The mixture did not turn blue/purple.

The mixture of 10 µL of the test item per 90 µL distilled water showed no colouring detectable by unaided eye-assessment.

The mean relative tissue viability (% negative control) was >50% (88.4%) after 15 min. treatment and 42 h post incubation.

The controls confirmed the validity of the study. The mean OD₅₅₀of the six blank values was <0.1. The mean absolute OD₅₅₀ of the three negative control tissues was 0.6 and ≤ 1.5. The mean relative tissue viability (% negative control) of the positive control was 40% (15.7%). The maximum standard deviation of viability of replicate tissues of all dose groups was <18% (5.4% - 6.4%).

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

In an in vitro Human Skin Model Test (EPISKIN-SM™) conducted to OECD TG 439 and GLP, the mean relative tissue viability (% negative control) was >50% (88.4%) after 15 min. treatment and 42 h post incubation for dibutoxy(dimethyl)silane. This result is negative for skin irritating potential.