Triethoxy(vinyl)silane

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

9 May to 10 June 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to a test protocol that is comparable to the appropriate OECD test guideline, and in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: GPMT (Magnusson & Kligman, 1970)

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The test was performed in 1988 when the OECD Guideline 406 adopted in 1992 was the current version. According to this guideline "the Guinea Pig Maximisation Test (GPMT) [...] and the non-adjuvant Buehler Test are given preference over other methods".

Test material

Test material information

Constituent 1

Reference substance name:

Triethoxy(vinyl)silane

EC Number:

201-081-7

EC Name:

Triethoxy(vinyl)silane

Cas Number:

78-08-0

Molecular formula:

C8H18O3Si

IUPAC Name:

triethoxy(vinyl)silane

In vivo test system

Test animals

Species:

guinea pig

Strain:

Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Murphy Breeding Labs Inc.
- Age at study initiation: "young adult"
- Weight at study initiation: 358 - 544 g
- Housing: 1/suspended mesh cage
- Diet: standard diet ad libitum
- Water: drinking water ad libitum
- Acclimation period: at least 4 days

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

IN-LIFE DATES: From: 1988-05-09 To: 1988-06-10

Study design: in vivo (non-LLNA)

Induction

Route:

intradermal and epicutaneous

Vehicle:

other: 95% ethanol for topical and injection induction phases

Concentration / amount:

intradermal induction: 1:1 FCA:distilled water; 100% test material (TM); 50% TM in 1:1 FCA:distilled water
topical induction: 10% TM in 95% ethanol

Day(s)/duration:

0-9

Challenge

No.:

#1

Route:

epicutaneous, semiocclusive

Vehicle:

other: acetone

Concentration / amount:

topical challenge: 1% in acetone

Day(s)/duration:

12-16

No. of animals per dose:

10/sex (test group)
5/sex (in each case for +ve, vehicle and naive control groups)

Details on study design:

RANGE FINDING TESTS:
primary irritation - injection: tested at 1-100% (in 95% ethanol where applicable)
primary irritation - topical: tested at 0.5-100% (in 95% ethanol or acetone where applicable)

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal-3 paired injections; topical)
- Exposure period: topical 48 h
- Test groups: 10/sex
- Control group: +ve 5/sex; -ve 5/sex
- Site: two rows of 3 sites, one row either side of dorsal mid-line
- Frequency of applications: intradermal treatment day 0; topical induction on day 5-9 (not specified)
- Duration: induction period continues to day 11-15 following start of topical induction (not specified)
- Concentrations:
intradermal: 1:1 FCA:distilled water; 100% TM; 50% TM in 1:1 FCA:distilled water
topical: 10% TM in 95% ethanol

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 12-16 days following start of topical induction (not specified)
- Exposure period: 24 h
- Test groups: 10/sex
- Control group: +ve 5/sex; -ve 5/sex
- Site: flank
- Concentrations: 1% TM in acetone
- Evaluation (hr after challenge): 24 and 48 h following patch removal

Challenge controls:

-ve (vehicle) control: 100% acetone
naive control
+ve control: 5% formaldhyde in distilled water

Positive control substance(s):

yes

Remarks:

formaldehyde

Results and discussion

Positive control results:

Based on the incidence index of 100%. The positive control material (5% formaldehyde) was judged to be a sensitising agent under the conditions of this study.

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100% TM (intradermal induction), 1% TM challenge

No. with + reactions:

3

Total no. in group:

20

Clinical observations:

grade 1 response

Results 2

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100% TM (intradermal induction), 1% TM challenge

No. with + reactions:

3

Total no. in group:

20

Clinical observations:

grade 1 response

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0% TM (intradermal induction), 1% TM challenge

No. with + reactions:

0

Total no. in group:

10

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0% TM (intradermal induction), 1% TM challenge

No. with + reactions:

0

Total no. in group:

10

Results 5

Reading:

1st reading

Hours after challenge:

24

Group:

other: challenge control

Dose level:

1% TM (challenge)

No. with + reactions:

0

Total no. in group:

10

Results 6

Reading:

2nd reading

Hours after challenge:

48

Group:

other: challenge control

Dose level:

1% TM (challenge)

No. with + reactions:

0

Total no. in group:

10

Results 7

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

5% (intradermal induction)

No. with + reactions:

10

Total no. in group:

10

Results 8

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

5% (intradermal induction)

No. with + reactions:

9

Total no. in group:

10

Any other information on results incl. tables

Table 1: Incidence of dermal response to challenge dosing

GROUP	MATERIAL	INTERVAL	No. RESPONDING GRADE =>1 (GRADE ±)*	NO. ANIMALS	MEAN SCORE
Test	TM	24h	3 (15)	20	0.5
		48h	3 (12)	20	0.5
	Vehicle (acetone)	Not reported
Positive control (5% formaldehyde)	5% aqueous formaldehyde	24h	10	10	1.2
		48h	9 (1)	10	1.1
Vehicle control (acetone)	Vehicle (acetone)	24h	0 (7)	10	0.4
		48h	0 (5)	10	0.3
Naïve animals	TM	24h	0 (6)	10	0.3
		48h	0 (5)	10	0.3
	5% aqueous formaldehyde	24h	0 (10)	10	0.5
		48h	0 (4)	10	0.2

*Skin reactions were graded as follows:

0 no reaction

± slight patchy erythema (apparently scored as 0.5)

1 slight but confluent or moderate patchy erythema

2 moderate erythema

3 severe erythema

The pattern of responses of grade 1 or greater (considered indicative of a sensitization response providing grades of less than 1 were found in "respective control groups") was 4/20 (20%; at 24h or 48h) in the test groups compared to 0/10 in naive controls, which was said to indicate mild sensitization. This finding would not meet EC criteria for skin sensitization.

Applicant's summary and conclusion

Interpretation of results:

other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008

Conclusions:

In a Guinea pig Maximisation study that was conducted using the Magnusson and Kligmann (1970) protocol, with minor deviations, and to GLP (reliability score 1) concluded triethoxy(vinyl)silane to be mildly sensitizing. However, in OECD TG 406 a positive response rate of 30% must be met for a substance to be concluded to be a mild/moderate sensitiser. In this test the positive response rate was 20%, and therefore according to current criteria would be negative. In addition the control animal mean scores were not significantly different to those of the test substance.