Distillation residues of butyraldehyde, 2-ethylhexenal and isobutanal hydrogenation by-products

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 August 2010 - ..................................

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Compliant to GLP and testing guideline; adequate coherence between data, comments and conclusions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Remarks:

deviations to study plan but not to guideline

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

Remarks:

idem above

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Details on test material:

- Name of test material (as cited in study report): distillation residues of butyraldehyde, 2-ethylhexenal and isobutanal hydrogenation by-products
- Physical state: yellow liquid
- Purity: not indicated (complex composition)
- Lot/batch No.: LR_OXO_2010-07-12
- Date of analysis: 12 July 2010
- Expiration date of the lot/batch: July 2011
- Storage conditions of test material: at +4°C and under nitrogen gas.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Breeder: Hypharm, La Corbière, Roussay, France
- Age at study initiation: 2 to 4 months old
- Weight at study initiation: 3.0 +/- 0.2 kg
- Housing: individually housed in Techniplast cages
- Diet (e.g. ad libitum): free access to breeding pelleted diet "type 110C"
- Water (e.g. ad libitum): tap water (filtered using a 0.22 µm filter) contained in bottles
- Acclimation period: at least 5 days before the beginning of the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 ± 3°C
- Humidity (%): 50 ± 20%,
- Air changes (per hr): approximately 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/12 h (7:00 - 19:00).

IN-LIFE DATES: From: 17 August 2010 To: 14 September 2010.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

other: clipped

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL
- Concentration (if solution): not applicable.

Duration of treatment / exposure:

3 minutes, 1 hour, 4 hours.

Observation period:

1 hour, 24, 48 and 72 hours after removal of the dressing and then daily until the reversibility of cutaneous reactions (day 7) or the end of the observation period.

Number of animals:

Two males and one female.

Details on study design:

TEST SITE
- Area of exposure: anterior left flank: application for 3 minutes, anterior right flank: application for 1 hour, or the piosterior right flank: application
4 hours
- % coverage: 6 cm2
- Type of wrap if used: gauze pad held in place by a non-irritation semi-occlusive dressing and a restraining bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): dry cotton pad
- Time after start of exposure: at removal of each dressing.

SCORING SYSTEM:
Dermal irritation was evaluated for each animal according to the following scoring scale:

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) to slight eschar formation (injuries in depth) 4

Edema formation
. no edema 0
. very slight edema (barely perceptible) 1
. slight edema (edges of area well-defined by definite raising) 2
. moderate edema (raised approximately 1 millimeter) 3
. severe edema (raised more than 1 millimeter and extending beyond area
of exposure) 4

Any other lesions were noted.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: 24 h 48 h 72 h

Score:

3

Max. score:

3

Reversibility:

fully reversible within: 11 days

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: 24 h, 48 h, 72 h

Score:

1.3

Max. score:

2

Reversibility:

fully reversible within: 5 days

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: 24 h, 48 h, 72 h

Score:

2.3

Max. score:

3

Reversibility:

fully reversible within: 10 days

Results 4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: 24 h, 48 h, 72 h

Score:

1.3

Max. score:

2

Reversibility:

fully reversible within: 8 days

Results 5

Irritation parameter:

edema score

Basis:

animal #2

Time point:

other: 24 h, 48 h, 72 h

Score:

0.3

Max. score:

1

Reversibility:

fully reversible within: 4 days

Results 6

Irritation parameter:

edema score

Basis:

animal #3

Time point:

other: 24 h, 48 h, 72 h

Score:

0.3

Max. score:

1

Reversibility:

fully reversible within: 7 days

Other effects:

After a 3-minute exposure (one animal), dryness of the skin was observed from day 4 until day 15.

After a 1-hour exposure (one animal), dryness of the skin was observed from day 3 until day 15.

After a 4-hour exposure (three animals), dryness of the skin was recorded from day 3 or 4 until the end of the observation period (day 15).

Applicant's summary and conclusion

Interpretation of results:

irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test item, distillation residues of butyraldehyde, 2-ethylhexenal and isobutanal hydrogenation by-products, was irritant when applied topically to rabbits.

Executive summary:

The objective of this study was to evaluate the potential of the test item, distillation residues of butyraldehyde, 2-ethylhexenal and isobutanal hydrogenation by-products, to induce skin irritation following a single topical application to rabbits according to OECD (No. 404, 24th April 2002) and Commission Regulation (EC) (No. 440/2008, B.4, 30 May 2008) guidelines.

The study was conducted in compliance with the principles of Good Laboratory Practice.

 

Methods

The test item, distillation residues of butyraldehyde, 2-ethylhexenal and isobutanal hydrogenation by-products, was first applied for periods of 3 minutes, 1 hour and 4 hours to a single male New Zealand White rabbit.

Since the test item was not severely irritant or corrosive to the skin on the first animal, it was then applied for 4 hours simultaneously to two other animals.

The quantity of the test item administered was 0.5 mL.

The test item was placed on a dry gauze pad, which was thenapplied to an area of the skin of approximately 6 cm² of the animals. The gauze pad was held in place by a non-irritation semi-occlusive dressing and a restraining bandage.After required period of contact with the skin, the dressings were removed.

For each exposure period, cutaneous reactions were evaluated approximately 1 hour, 24, 48 and 72 hours after removal of the dressing and then daily until the reversibility of cutaneous reactions (day 7) or the end of the observation period.

Body weight was recorded at the beginning and the end of the observation period. On completion of the observation period, the animals were used subsequently for the evaluation of the ocular irritation potential of the same test item.

The mean values of the scores for erythema and edema were calculated for each animal.

The interpretation of results was carried out according to the classification criteria laid down in Council Directive 67/548/EEC (and subsequent adaptations).

 

Results

After a 3-minute exposure (one animal), a very slight or well-defined erythema was noted from day 1 until the end of the observation period (day 15). Dryness of the skin was observed from day 4 until day 15.

After a 1-hour exposure (one animal), a very slight or well-defined erythema was noted from day 1 until the day 14. Dryness of the skin was observed from day 3 until day 15.

After a 4-hour exposure (three animals), a very slight or well-defined erythema was noted in one animal (female No. 520) from day 1 until day 5. In addition, a very slight edema (grade 1) was noted on day 4 and dryness of the skin was observed from day 4 until day 6.

In the two other animals, a very slight to moderate erythema was noted from day 1 until day 10 (male No. 521) or 11 (male No. 517). A very slight or slight edema was observed from day 2 until day 8 (No. 517) or from day 4 until day 7 (No. 521). Dryness of the skin was recorded from day 3 or 4 until the end of the observation period (day 15).

Mean scores over 24, 48 and 72 hours for each animal were 3.0, 1.3 and 2.3 for erythema and 1.3, 0.3 and 0.3 for edema.

Conclusion

The test item, distillation residues of butyraldehyde, 2-ethylhexenal and isobutanal hydrogenation by-products, was irritant when applied topically to rabbits.

 According to the classification criteria laid down in Council Directive 67/548/EEC (and subsequent adaptations), the test item should be classified as irritating and assigned the symbol Xi, the indication of danger "Irritant" and the risk phrase R 38: "Irritating to skin".