L-isoleucine

Endpoint summary

Description of key information

L-isoleucine is not irritating to skin or eye.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin 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

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Centre Lagro, France
- Age at study initiation: young adult
- Weight at study initiation:2015, 1965 and 1975g
- Housing: individually in stainless steel cages with perforated floor
- Diet: standard laboratory diet, ad libitum
- Water: tap water, ad libitum
- Quarantine/acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20+/-3°C
- Humidity (%): 30-70%. Upper limit once up to 87.9% because of wet cleaning of the animal room
- Air changes (per hr): 10

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

water

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.5 g

VEHICLE
- Amount(s) applied: 0.5 mL

Duration of treatment / exposure:

4 hours

Observation period:

3 days

Number of animals:

3

Details on study design:

TEST SITE
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 to avoid abrasions. The clipping was repeated if considered necessary. Just prior to application, a skin site suitable for application was selected on the clipped flank of the animal. A plastic cup with a diameter of ca. 2.5 cm was loaded with an amount of 0.5 g of the test substance and moistened with 0.5 mL of water. The loaded cup was fixed to the selected application site by means of semi-occlusive, adhesive tape (Leukopor, BDF, Germany). Subsequently, the entire trunk of the rabbit was wrapped with a self-adhesive-gauze (Fixomull, BDF, Germany) to maintain the cup in position and to retard evaporation of volatile substances. The gauze was additionally fastened with two strips of tape (Leukoflex, BDF, Germany).

REMOVAL OF TEST SUBSTANCE
After a 4-hour exposure period, the cup was removed and the test site was cleaned with a tissue moistened with water. One hour after treatment, the resulting skin reactions were evaluated by the method of Draize et al. Further skin readings were made at approximately 24, 48 and 72 h after treatment.

SCORING SYSTEM: Draize

Irritation parameter:

erythema score

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable: no effects observed

Irritation parameter:

edema score

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable: no effects observed

Interpretation of results:

not irritating

Conclusions:

L-isoleucine did not cause any skin effects in rabbits.

Executive summary:

A sample of L-isoleucine was tested for acute dermal irritating properties in an experiment with 3 albino rabbits, according to EEC Directive 92/69/EEC method B.4 and OECD Guideline 404.

L-isoleucine did not cause any skin effects in rabbits.

According to the EC standards, L-isoleucine is not irritating to (human) skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

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

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.

Irritation parameter:

cornea opacity score

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Irritation parameter:

iris score

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Irritation parameter:

conjunctivae score

Basis:

animal: all 3 animals

Time point:

other: 1h

Score:

1

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

other: 24h

Score:

1

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

conjunctivae score

Basis:

animal: #2 and #3

Time point:

other: 24h

Score:

0

Max. score:

4

Irritation parameter:

conjunctivae score

Basis:

animal: all 3 animals

Time point:

other: 48 and 72h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

Irritation parameter:

other: discharge

Basis:

animal: all 3 animals

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

4

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.

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.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

One in vivo study is available (key - Prinsen, 2005) in which a sample of L-isoleucine was tested for acute dermal irritating properties in an experiment with 3 albino rabbits, according to EEC Directive 92/69/EEC method B.4 and OECD Guideline 404.

This study indicated that L-isoleucine did not cause any skin effects in rabbits.

Regarding eye irritation a sample of L-isoleucine was tested in an experiment with 3 albino rabbits according to OECD 405 and EU B.5 Guidelines (key - Prinsen, 2005). L-isoleucine caused slight swelling of the conjunctivae, however, 48 hours after treatment all eyes had cleared completely.

Justification for classification or non-classification

According to sections 3.2 (Tables 3.2.1 and 3.2.2) and section 3.3 (Tables 3.3.1 and 3.3.2) of the CLP Regulation No 1272/2008, L-isoleucine is not irritating to (human) skin or eye.