L-isoleucine

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

L-isoleucine

EC Number:

200-798-2

EC Name:

L-isoleucine

Cas Number:

73-32-5

Molecular formula:

C6H13NO2

IUPAC Name:

L-isoleucine

Test material form:

solid: crystalline

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Species: SPF bred New Zealand White albino
- Source: Centre Lagro, France
- Age at study initiation: young adult males
- Weight at study initiation: 1950, 1870 and 1890g
- Housing: individually in stainless steel cages with perforated floor
- Diet (e.g. ad libitum): standard laboratory diet, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 +/- 3°C
- Humidity (%): 30-70%. Upper limit once up to 87% because of wet cleaning of the animal room
- Air changes (per hr): ca. 10
- Photoperiod (hrs dark / hrs light): 12 hours light / 12 hours dark

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: other eye of test animals served as controls

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): ca. 0.07 g (0.1 mL)

Duration of treatment / exposure:

Single exposure. Eyes were not rinsed.

Observation period (in vivo):

1, 24, 48 and 72 hours after treatment.

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
At one hour after treatment, slight amounts of the test substance were still present in the conjunctival cul-de-sac of the rabbits. These remnants were removed by manipulation of the eye-lids.

SCORING SYSTEM:
Corneal opacity (0-4)
Area of cornea affected (0-4)
Iris (0-4)
Redness of the conjunctivae (0-4)
Chemosis (0-4)
Ocular discharge (0-4)

The in vitro/ex-vivo Non-GLP Chicken Enucleated Eye Test did not show significant sings of irritation. Therefore, it was decided to proceed with the in-vivo test. Both eyes of rabbits selected were examined just before testing. Only rabbits without observable eye defects were used.
The study was carried out with 3 rabbits (started with one rabbit and continued with 2 rabbits 1 hour later) and each rabbit was treated as follows: an amount of ca. 0.1 mL (ca. 0.07g) of the test substance was instilled in the conjunctival cul-de-sac of one of the eyes. After administration, the upper and lower eye lid were carefully closed and subsequently held together for at least one second before releasing, to prevent loss of material. The other eye remained untreated, served as a control. The reactions of the test eye were judged at ca. 1, 24, 48 and 72 hours.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Results 2

Irritation parameter:

iris score

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Results 3

Irritation parameter:

conjunctivae score

Basis:

animal: all 3 animals

Time point:

other: 1h

Score:

1

Max. score:

4

Reversibility:

fully reversible

Results 4

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

other: 24h

Score:

1

Max. score:

4

Reversibility:

fully reversible

Results 5

Irritation parameter:

conjunctivae score

Basis:

animal: #2 and #3

Time point:

other: 24h

Score:

0

Max. score:

4

Results 6

Irritation parameter:

conjunctivae score

Basis:

animal: all 3 animals

Time point:

other: 48 and 72h

Score:

0

Max. score:

4

Results 7

Irritation parameter:

chemosis score

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Results 8

Irritation parameter:

other: discharge

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Any other information on results incl. tables

At 1 hour after treatment, slight redness of the conjunctivae was observed in the three rabbits.

At 24 hours after treatment, slight redness of the conjunctivae was observed in one of the three rabbits.

At 48 and 72 after removal, no signs of irritation were observed in any of the 3 rabbits.

According to the EC-standarts (Official Journal of the European Communicites, L 110A, Volume 36, 4 May 1993), L-isoleucine is not irritating to (human) eyes.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Conclusions:

Iso-leucine is not irritating to (human) eyes.

Executive summary:

A sample of L-isoleucine was tested for acute dermal irritating properties in an experiment with 3 albino rabbits according to OECD 405 and EU B.5 Guidelines.

L-isoleucine caused slight swelling of the conjunctivae. At 48 hours after treatment, all eyes had cleared completely.

According to the EC-standarts (Official Journal of the European Communicites, L 110A, Volume 36, 4 May 1993), L-isoleucine is not irritating to (human) eyes.