4-methylpentan-2-one

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented, according to accepted guidelines

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

yes

Remarks:

- room temperature was 16 to 22 °C, relative humidity was 40 to 80%, and artificial lighting was 14 hr.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Version / remarks:

1992

Deviations:

not specified

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4-methylpentan-2-one

EC Number:

203-550-1

EC Name:

4-methylpentan-2-one

Cas Number:

108-10-1

Molecular formula:

C6H12O

IUPAC Name:

4-methylpentan-2-one

Details on test material:

- Name of test material (as cited in study report): Methyl iso butyl ketone.
- Physical state: Colourless liquid.
- Analytical purity: 99.5%.
- Lot/batch No.: D215600281.
- Expiration date of the lot/batch: 22 November 1996.
- Stability under test conditions: Not reported.
- Storage condition of test material: Stored at room temperature in the original container.

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Charles River UK Ltd., Margate.
- Age at study initiation: 13 to 16 weeks old.
- Weight at study initiation: 2.5 to 3.29 kg.
- Housing: Housed in floor-pens, each accomodating one animal.
- Diet (e.g. ad libitum): SQC TRB Rabbit Diet 9603 (pelleted) from Harlan Teklad, Bicester, ad libitum.
- Water (e.g. ad libitum): Mains water, ad libitum.
- Acclimation period: At least 3 weeks.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 16 to 22.
- Humidity (%): 40 to 80.
- Air changes (per hr): at least 10.
- Photoperiod (hrs dark / hrs light): 10 hrs dark / 14 hrs light.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL.
- Concentration (if solution): Undiluted.

Duration of treatment / exposure:

Single exposure.

Observation period (in vivo):

Up to 72 hours.

Number of animals or in vitro replicates:

3

Details on study design:

One dose consisting of 0.1 mL (after instillation, the eyelids were held closed for a few seconds to prevent loss of the dose). Ocular changes were assessed and recorded immediately, one half-hour, 1 and 4 hours after treatment on Day 1, and 24, 48, and 72 hours after instillation.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): No.


SCORING SYSTEM:
The “initial sting” response was assessed and recorded immediately after instillation of the test article. The response was graded according to the following scheme:

Response of animal: Grade: Sting response
No response: 0: None
A few blinks only, normal within two minutes: 1: practically none
Rabbit blinks and attempts to open eye but reflex closes it: 2: Slight
Rabbit keeps eye shut and puts pressure on it, may rub eye: 3: Moderate
Rabbit holds eye tightly shut, may struggle or squeal: 4: Marked

Ocular opacity- degree of density (area most dense taken for reading): Grade

No ulceration or opacity: 0
Scattered or diffused areas of opacity other than slight dulling of normal lustre, details of iris clearly visible: 1
Easily discernible translucent areas, details of iris slightly obscured: 2
Nacreous areas, no details of iris visible, but size of pupil barely discernible: 3
Opaque cornea, iris not discernible through the opacity: 4

Cornea: area of corneal opacity: Grade

Total area of opacity amounts to <25% of corneal area: 1
Area of opacity amounts to 25 - <50% of corneal area: 2
Area of opacity amounts to 50 - <75% of corneal area: 3
Area of opacity amounts to 75% or more of corneal area: 4

Iris: Grade

No reaction: 0
Markedly deepened rugae, congestion, swelling, moderate circumcorneal hyperaemia, or injection, any of these or combination of any thereof, iris still reacting to light: 1
No iridial reflex to light, haemorrhage, gross destruction (any or all of these): 2

Conjunctivae Redness (refers to the most severe reading of palpebral and bulbar conjunctivae, as compared to the right, control eye): Grade

Blood vessels normal: 0
Some blood vessel definitely hyperaemic (injected): 1
Diffuse, crimson colour, individual vessels not easily discernible: 2
Diffuse beefy red appearance: 3

Chemosis (assessments included nictating membranes): Grade

No swelling: 0
Any swelling above normal: 1
Obvious swelling with partial eversion of lids: 2
Swelling with lids about half-closed: 3
Swelling with lids more than half-closed: 4

Conjunctivae- discharge: Grade

No discharge: 0
Any discharge greater than normal, not including the small amount normally present in the inner canthus: 1
Discharge with moistening of eyelids and hairs just adjacent to the eye: 2
Discharge with moistening of eyelids and hair for a considerable area around the eye: 3



TOOL USED TO ASSESS SCORE: Any ocular changes (e.g., vascularisation, pannus formation) excluded from this standard grading scheme were recorded in detail. The treated eyes were examined visually or with the aid of a pencil-beam torch or other device to illuminate or magnify the eye during examination. At examinations carried out 24 hours after treatment and on any subsequent examination at the discretion of the observer the cornea was subject to application of 2% aqueous fluorescein solution followed by irrigation with water for irrigation. The corneal surface was then illuminated by an ultraviolet source and inspected for areas of absorption of the fluorescing dye that indicate epithelial disruption.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Results 2

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Results 3

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Results 4

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible

Results 5

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible

Results 6

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible

Results 7

Irritation parameter:

conjunctivae score

Remarks:

- Redness

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

3

Reversibility:

fully reversible

Results 8

Irritation parameter:

conjunctivae score

Remarks:

- Redness

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

3

Reversibility:

fully reversible

Results 9

Irritation parameter:

conjunctivae score

Remarks:

- Redness

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

3

Reversibility:

fully reversible

Results 10

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Results 11

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Results 12

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritant / corrosive response data:

Instillation of methyl iso butyl ketone caused slight or practically no initial sting responses.

Conjunctival irritation reactions not exceeding a crimson appearance, slight chemosis and an ocular discharge were apparent in all rabbits during the four hour period following instillation of the test article. All conjunctival reactions had resolved 24 hours after treatment. The iris remained overtly unaffected by the test article.

No corneal opacities developed in any rabbit. A small part of the cornea of one rabbit was permeable to applied fluorescein 24 hours after instillation of the test article. This was taken to indicate minor disruption of the corneal epithelium. The cornea proved to be impermeable to applied fluorescein on the following day. See Table 1 (Attached) for individual data and Table 2 (Attached) for Group mean values.

Other effects:

No observations indicative of systemic toxicity or ill health were noted for any rabbits during the course of the study.

Applicant's summary and conclusion

Interpretation of results:

slightly irritating

Remarks:

Migrated information not classified Criteria used for interpretation of results: other: CLP (EC 1272/2008)

Conclusions:

A single instillation of methyl iso butyl ketone into the conjunctival sac of three rabbits caused changes of the conjunctivae that resolved within 24 hours and minor disturbance of the corneal epithelium that resolved within 48 hours.

Executive summary:

An eye irritation study on methyl iso butyl ketone has been performed in accordance with OECD Guidelines for the Testing of Chemicals No. 405 and in compliance with GLP (Gardner, 1996).  In this study, 0.1 mL of undiluted methyl iso butyl ketone was instilled into one conjunctival sac of each of 3 New Zealand White rabbits.  Ocular changes were assessed 0.5, 1, 4, 24, 48, 72 hours after treatment, and scoring was performed according to guideline methods.  No clinical signs of systemic toxicity or ill health were observed in any rabbit during the course of the study.  Instillation of methyl iso butyl ketone caused slight or practically no initial sting response.  All rabbits developed conjunctival irritation (not exceeding a crimson appearance), slight chemosis, and an occular discharge during the 4-hour period following instillation of the test substance.  All conjunctival reactions were resolved 24 hours after treatment. The iris remained overtly unaffected by the test substance. No corneal opacities developed in any rabbit. A small part of the cornea of one rabbit was permeable to applied fluorescein 24 hours after instillation of the test article, indicative of a minor disruption of the corneal epithelium; however, the cornea was proved to be impermeable to applied fluorescein on the following day. All individual mean scores over 24, 48 and 72 h were 0. Under the conditions of this study, methyl iso butyl ketone was considered to be slightly irritating to rabbit eyes.