Ethyl 2-methylbutyrate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 May to 6 June 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD 402

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl 2-methylbutyrate

EC Number:

231-225-4

EC Name:

Ethyl 2-methylbutyrate

Cas Number:

7452-79-1

Molecular formula:

C7H14O2

IUPAC Name:

ethyl 2-methylbutanoate

Constituent 2

Reference substance name:

Ethyl Methylbutyrate-2

IUPAC Name:

Ethyl Methylbutyrate-2

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): Ethyl Methylbutyrate-2
- Molecular formula (if other than submission substance): C7H14O2
- Molecular weight (if other than submission substance): 130.21 g/mol
- Physical state: Colourless liquid
- Analytical purity: 99.4%
- Lot/batch No.: 20010036
- Storage condition of test material: Approximately 4°C in the dark
- Other:
- Date received: 08 May 2000

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd, Margate, Kent
- Age at study initiation: approximately 8 to 12 weeks old
- Weight at study initiation: males weighed 222 to 231g, and the females 215 to 226g
- Fasting period before study: No details provided in report
- Housing: The animals were housed in suspended polypropylene cages furnished with woodflakes. The animals were housed individually during the 24-hour exposure period and in groups of five, by sex, for the remainder of the study.
- Diet (e.g. ad libitum): Free access to mains drinking water and food (Rat and Mouse Expanded Diet No.1, Special Diets Services Limited, Witham, Essex, UK) was allowed throughout the study.
- Water (e.g. ad libitum): Free access to mains drinking water and food (Rat and Mouse Expanded Diet No.1, Special Diets Services Limited, Witham, Essex, UK) was allowed throughout the study.
- Acclimation period: minimum acclimatisation period of five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25
- Humidity (%): 30 to 70
(Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study).
- Air changes (per hr): approximately 15
- Photoperiod (hrs dark / hrs light): 12 hours continuous light and 12 hours darkness

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

not specified

Amount / concentration applied:

TEST SITE
- The calculated volume of the test material, as received, was applied uniformly to an area of shorn skin (approximating to 10% of the total body surface area) using a graduated syringe. A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self-adhesive bandage. The animals were caged individually for the 24-hour exposure period. Shortly after dosing the dressings were examined to ensure that they were securely in place.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): The bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test material. The animals were returned to group housing for the remainder of the study period.
- Time after start of exposure: After the 24-hour contact period

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Dose volume 2.33 ml/kg and Specific gravity 0.861 (Dose level 2000 mg/kg)

Duration of treatment / exposure:

24 hours

Observation period:

14 days

Number of animals:

5/sex/group

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The animals were observed for deaths or overt signs of toxicity ½, 1, 2 and 4 hours after dosing and subsequently once daily for 14 days. Individual bodyweights were recorded prior to application of the test material on Day 0 and on Days 7 and 14.
- Necropsy of survivors performed: At the end of the study the animals were killed by cervical dislocation and subjected to gross pathological examination. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.
- Other examinations performed: After removal of the dressings and subsequently once daily for 14 days, the test sites were examined for evidence of primary irritation and scored according to the following scale from Draize J H (1977) “Dermal and Eye Toxicity Tests” In: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC p.31 (see attached report for details). Any other skin reactions, if present were also recorded.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

There was no evidence of skin irritation in any animal at any timepoints. Mean scores: eythema 0, oedema 0, other skin effects 0.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information

Conclusions:

Based on the results of an acute dermal toxicity study in male and female rats at 2000 mg/kg EMB is considered not to be irritating to skin.

Executive summary:

A group of ten rats (five males and five females) was given a single 24-hour, semi-occluded dermal application to intact skin at a dose level of 2000 mg/kg body weight. The animals were observed for fourteen days after the day of treatment and were then killed for gross pathological examination.

 There were no deaths. No signs of systemic toxicity or dermal irritation were noted during the study.