(E)-4-Ethoxy-1,1,1-trifluoro-3-buten-2-one (stabilized with BHT)

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 Sept.-09 Oct. 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognised method, and under GLP. The substance is adequately characterised with its purity. Therefore full validation applies.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

24 April 2002

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate from 2004-08-19

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

liquid

Details on test material:

N.B. This batch BWG 60000 was used in several studies with some descriptive information diverging slightly between the reports (for further details, see below in this field and in the following field).

- Appearance:
* Clear yellowish liquid was mentioned in the 2007 and 2008 Notox reports dealing with physico-chemical properties and in the in 2007 Solvay Pharma report dealing with ASRI test.
* Yellow liquid was mentioned in the 2006 and 2007 TNO reports dealing with toxicological endpoints.
- Storage conditions:
* Storage in freezer (=< -15°C) in the dark under nitrogen was mentioned in the 2007 and 2008 Notox reports dealing with physico-chemical properties.
* Storage in freezer (< -10°C) was mentioned in the 2007 Solvay Pharma report dealing with ASRI test.
* Storage at < -18°C (with or without the mention "protected from light") was mentioned in the 2006 and 2007 TNO reports dealing with toxicological endpoints.
- Stability under storage conditions: Stable.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: SPF bred New Zealand White albino rabbits obtained from Centre Lagro, France.
- Sex: Males.
- Age at study initiation: Young adults.
- Weight at study initiation: 1830, 1874 and 1854 g.
- Housing: Individually housed in stainless steel cages with perforated floor.
- Diet: Standard laboratory diet ad libitum. Each batch of this diet was analysed by the supplier (SDS Special Diets services, Whitham, England) for the nutrients and contaminants and the results were kept available in the archives.
- Water: Tap water (N.V. Hydron Midden-Nederland) ad libitum. Results of routine physical, chemical and rnicrobiological examination of drinking water as conducted by the supplier were kept available in the archives.
The results of diet and water analyses were considered acceptable for this study.
- Acclimation period: 5 to 6 days.

ENVIRONMENTAL CONDITIONS
- Temperature: 20 +/- 3 °C.
- Humidity: 45 - 72%.
- Air changes: ca 10 air changes per hour.
- Photoperiod: 12 hours light/12 hours dark cycle.

IN-LIFE DATES:
- Start of study: 18/09/2006 (one rabbit) and 19/09/2006 (two rabbits).
- Termination of study: 09/10/2006.

Test system

Type of coverage:

occlusive

Preparation of test site:

clipped

Remarks:

Three days prior to the start of the study, the hair was removed from the back and flanks of the animals using electric clippers in a way as to avoid abrasions. The clipping was repeated if considered necessary.

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.5 mL.
- Concentration (if solution): The test substance is a liquid and was used as it is without dilution.

Duration of treatment / exposure:

Exposure period of ca. 4 hours.

Observation period:

Observation period of 21 days.

Number of animals:

3 rabbits.

Details on study design:

TEST SITE
- Area of exposure: 2.5 x 2.5 cm.
- % coverage: Not clearly reported (an amount of 0.5 mL of the test substance was distributed over a patch measuring 2.5 x 2.5 cm).
- Type of wrap if used: The patch was fixed to the selected application site by means of adhesive tape and the entire trunk of the rabbit was wrapped with an impervious material to maintain the test patch in position.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Not specified.
- Time after start of exposure: After an exposure period of ca. 4 hours the patch and the material applied were removed.

OBSERVATION TIME POINTS
Skin readings were made ca. one hour after the end of exposure and after approximately 24, 48, and 72 h and after 7, 14 and 20/21 days.

SCORING SYSTEM:
- Method of calculation: Draize et al. (J. Pharmacol. Exp. Ther. 82 (1944) 377-390).
A. Erythema and eschar formation
No erythema = 0
Very slight erythema (barely perceptible) = 1
Well-defined erythema = 2
Moderate to severe erythema = 3
Severe erythema (beet redness); eschar formation (injuries in depth: ischemic necrosis, haemorrhages, and incrustation) = 4
B. Oedema formation
No oedema = 0
Very slight oedema (barely perceptible) = 1
Slight oedema (edges of area well-defined by definite raising) = 2
Moderate oedema (raised approximately l millimeter) = 3
Severe oedema (raised more than 1 millimeter, extending beyond the area of exposure) = 4

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Remarks on result:

other: In combination with slight ischemic necrosis after 24 h and in combination with slight incrustation after 48 and 72 h.

Results 2

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Results 3

Irritation parameter:

edema score

Basis:

animal #1

Time point:

48 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Results 4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Results 5

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Remarks on result:

other: In combination with slight ischemic necrosis after 24 h and in combination with slight incrustation after 48 and 72 h.

Results 6

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Results 7

Irritation parameter:

edema score

Basis:

animal #2

Time point:

48 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Results 8

Irritation parameter:

edema score

Basis:

animal #2

Time point:

72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Results 9

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

4

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Remarks on result:

other: In combination with slight ischemic necrosis after 24 h and in combination with slight incrustation after 48 and 72 h.

Results 10

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Results 11

Irritation parameter:

edema score

Basis:

animal #3

Time point:

48 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Results 12

Irritation parameter:

edema score

Basis:

animal #3

Time point:

72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 14 d

Remarks:

At 20/21 days after removal, these skin effects had cleared in the three rabbits.

Irritant / corrosive response data:

At 1 h after removal, well-defined erythema and moderate oedema were observed in the three rabbits.
At 24 h after removal, moderate erythema and moderate oedema were observed in the three rabbits. In addition, slight ischemic necrosis was observed.
At 48 and 72 h after removal, moderate erythema, slight ischemic incrustation and slight or moderate oedema were observed in the three rabbits.
At 7 days after removal, moderate or severe incrustation was observed. In one animal (#2), a few small areas of the incrustation had a black appearance
(haemorrhages). Because of the incrustation present, erythema and oedema could not be scored.
At 14 days after removal, slight, moderate or severe incrustation was observed. Animal #2 still showed the few small black areas. Another animal (#1) showed a few small wounds because of removal of the incrustation by the animal.
At 20/21 days after removal, these skin effects had cleared in the three rabbits, but decreased hair growth (alopecia) was observed on the entire test site of all animals.

Any other information on results incl. tables

Skin irritation scores of ETFBO, after a single 4-hour dermal exposure:

Animal	Hours (h) / days (d) after removal of the test material
	1 h	24 h	48 h	72 h	7 d	14 d	20/21 d
	A-B	A-B	A-B	A-B	A-B	A-B	A-B
#1	2-3	4^1-3	4^2-3	4^2-2	4^3?-?	4^3?-?	0^6-0
#2	2-3	4^1-3	4^2-3	4^2-2	4^4?-?	4^4?-?	0^6-0
#3	2-3	4^1-3	4^2-3	4^2 -2	4^3?-?	4^5?-?	0^6-0

A = erythema (including ischemia, haemorrhages and incrustation); B = oedema

¹= moderate erythema in combination with slight ischemic necrosis (erythema score = 4)

²= moderate erythema in combination with slight incrustation (erythema score = 4)

? = erythema and oedema not discernable because of the incrustation present

³= moderate incrustation (erythema score = 4)

⁴= severe incrustation (erythema score = 4)

⁵= slight incrustation (erythema score = 4)

⁶= decreased hair growth (alopecia)

 

Mean values for erythema and oedema of each rabbit scored at 24, 48 and 72 h after treatment with ETFBO: 

Animal	Erythema	Oedema
#1	4.0	2.7
#2	4.0	2.7
#3	4.0	2.7

 

Applicant's summary and conclusion

Interpretation of results:

Category 1 (corrosive) based on GHS criteria

Conclusions:

ETFBO was demonstrated to be corrosive to skin.

Executive summary:

The skin corrosion/irritation potential was investigated in a GPL-compliant study performed according to OECD test guideline 404.

The study was carried out with three male New Zealand White albino rabbits. Three days prior to the start of the study, the hair was removed from the back and flanks of the animals using electric clippers in a way as to avoid abrasions. The rabbits were treated as follows: just prior to application, a skin site suitable for application was selected on the clipped flank of the animal. An amount of 0.5 mL of the test substance was distributed over a patch measuring 2.5 x 2.5 cm and fixed to the selected application site by means of adhesive tape. The entire trunk of the rabbit was wrapped with an impervious material to maintain the test patch in position. After an exposure period of ca. 4 hours, the patch and the material applied were removed. Skin readings were made ca. one hour after the end of exposure and after approximately 24, 48, and 72 h and after 7, 14 and 20/21 days using the method of Draize et al. (1944).

At 1 h after removal, well-defined erythema and moderate oedema were observed in the three rabbits. At 24 h after removal, moderate erythema and moderate oedema were observed in the three rabbits. In addition, slight ischemic necrosis was observed. At 48 and 72 h after removal, moderate erythema, slight ischemic incrustation and slight or moderate oedema were observed in the three rabbits. At 7 days after removal, moderate or severe incrustation was observed. In one animal (#2), a few small areas of the incrustation had a black appearance (haemorrhages). Because of the incrustation present, erythema and oedema could not be scored. At 14 days after removal, slight, moderate or severe incrustation was observed. Animal #2 still showed the few small black areas. Another animal (#1) showed a few small wounds because of removal of the incrustation by the animal. At 20/21 days after removal, these skin effects had cleared in the three rabbits, but decreased hair growth (alopecia) was observed on the entire test site of all animals.

According to the GHS criteria, ETFBO has to be considered as corrosive to skin and has to be classified in Category 1 for skin corrosion.