Tetraethyl orthosilicate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992/10/05-1992/10/20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Tetraethyl orthosilicate

EC Number:

201-083-8

EC Name:

Tetraethyl orthosilicate

Cas Number:

78-10-4

Molecular formula:

C8H20O4Si

IUPAC Name:

tetraethyl orthosilicate

Test material form:

liquid

Test animals

Species:

rabbit

Strain:

other: Small white Russian, Chbb: MH, SPF

Details on test animals or test system and environmental conditions:

TEST ANIMALS

- Source: Dr. Karl Thomae GmbH Co, Biberach

- Weight at study initiation: 2-3 kg

- Housing: Conventional, individual containment in stainless steel cages

- Diet: Ssniff K 4-comprehensive feed for rabbits, ad libitum

- Water: municipal water, ad libitum

- Acclimation period: minimum of 14 days


ENVIRONMENTAL CONDITIONS

- Temperature (°C): 20 +/-3

- Humidity (%): 30-70

- Air changes (per hr): 15

- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Remarks:

other: intact skin

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL of test substance

- Concentration (if solution): undiluted

Duration of treatment / exposure:

4 hours

Observation period:

The treated area was scored for irritation at 30-60 minutes, 24, 48 and 72 hours following patch removal and on days 6, 8, 10 and 14 following patch removal.

Number of animals:

3M

Details on study design:

TEST SITE
- Area of exposure: 6 cm2 of shaved intact dorsal skin

- Type of wrap if used: covered with a layer of gauze, which was covered with a non-stick dressing and a semi-occlusive bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): rinsed with warm water.  

- Time after start of exposure: 4 hours

SCORING SYSTEM: According to guideline

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 10 days

Remarks on result:

probability of mild irritation

Remarks:

median

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

fully reversible within: 8 days

Remarks on result:

probability of mild irritation

Remarks:

median

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.67

Max. score:

4

Reversibility:

fully reversible within: 6 days

Remarks on result:

probability of mild irritation

Remarks:

median

Results 4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 10 days

Remarks on result:

probability of mild irritation

Remarks:

median

Results 5

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

fully reversible within: 8 days

Remarks on result:

probability of mild irritation

Remarks:

median

Results 6

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 6 days

Remarks on result:

probability of mild irritation

Remarks:

median

Irritant / corrosive response data:

Semi-occlusive application of tetraethyl orthosilicate caused localized medium erythema, and medium edema in all three animals after 24 hrs. These signs dissipated within 6 to 10 days.

Other effects:

Skin dryness and dandruff were evident as the erythema and edema alleviated, but these additional symptoms resolved within 14 days.

Any other information on results incl. tables

Table 1: Irritant/corrosive response data for each animal at each observation time up to removal of each animal from the test

 

Score at time point / Reversibility	Erythema	Edema
	Max. score: 3	Max. score: 4
60 min	2/2/2	4/3/3
24 h	2/3/2	3/3/3
48 h	2/3/2	2/3/2
72 h	2/3/1	1/3/1
6 days	1/2/0	1/2/0
8 days	1/0/0	1/0/0
10 days	0/0/0	0/0/0
14 days	0/0/0	0/0/0
Median 24h, 48h, 72h	2.22	2.33
Reversibility*)	c	c
Average time (unit) for reversion	6-10 days	6-10 days

 

*) Reversibility: c. = completely reversible; n.c. = not completely reversible; n. = not reversible

 

Applicant's summary and conclusion

Interpretation of results:

Category 3 (mild irritant) based on GHS criteria

Remarks:

Not classified according to Regulation (EC) No. 1272/2008

Conclusions:

In the key study conducted according to OECD Test Guideline 404 and in compliance with GLP (reliability score 1), tetraethyl orthosilicate was found to produce medium erythema and medium edema in the rabbit, with these symptoms dissipating within 6 to10 days, and all symptoms dissipating within 14 days. Tetraethyl orthosilicate is a non-irritant under Regulation (EC) No. 1272/2008.