L-leucine

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test performed according to GLP and internationally accepted study protocols. No deviations from protocol.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Revision of Guidelines for Single and Repeated Administration Toxicity Studies (notification n°88 of the Pharmaceutical Affairs Bureau, Ministry of Health and Welfare, Japan, August 1993.

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

L-leucine

EC Number:

200-522-0

EC Name:

L-leucine

Cas Number:

61-90-5

Molecular formula:

C6H13NO2

IUPAC Name:

L-leucine

Details on test material:

- Name of test material (as cited in study report): L-leu
- Physical state: white crystal or crystalline powder
- Analytical purity: 99.8%
- Lot/batch No.: 703ZK03
- Expiration date of the lot/batch: approx. 3 years
- Stability: stable in dry state
- Storage condition of test material: room temperature, in an airtight container, no exposure to high temperature or high humidity

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Japan
- Strain: Sprague-Dawley SPF [Crj:CD (SD)]
- Age at study initiation: 5 weeks
- Weight at study initiation: 164-186g (males), 120-144g (females)
- Fasting period before study: overnight, approx. 16 hours
- Housing: per 2 in stainless steel wire mesh cages (W254 x D350 x H170 mm)
- Diet (e.g. ad libitum): ad libitum, irradiation sterilized CRF-1, Oriental Yeast Co., Ltd
- Water (e.g. ad libitum): ad libitum, Gotemba Municipal Water Works, via automatic water supply system
- Acclimation period: 7 days (quarantine)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 +/- 3°C
- Humidity (%): 50 +/- 20%
- Air changes (per hr): 15 to 20 per hour
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From 22/09/1997 To 13/10/1997

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: gummi arabicum pulveratum + water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 5% w/v

MAXIMUM DOSE VOLUME APPLIED: 20 mL/ kg bw

DOSAGE PREPARATION: The requisite amounts of test article and gummi arabicum pulveratum (5% w/v in the final concentration) were weighed accurately. The test article was mixed with gummi arabicum pulveratum with agate morter (approx. 5 minutes) while adding water (for injection) to the proper quantity (Water for injection: JP, Otsuka Pharmaceutical Factory Inc., Lot n° 7D72), and test suspensions of the prescribed concentrations were prepared.

Preparation of test solutions was done at the time of use.

Control animals were administered 5 %w/v gummi arabicum solution.

Doses:

0, 500, 1000 and 2000 mg/kg bw

No. of animals per sex per dose:

6 males and 6 females per dose

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: frequently for the first 6 hours after dosing and once daily thereafter
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Statistics:

The lethal dose was estimated based on the cumulative mortaility for 14 days after administration. Body weights were subjected to multiple tests shown in a diagram available in the test report (Bartlett's Test, F-test, One-way analysis of variance, Kruskal-Wallis' Rank-Sum test, et cetera).

Results and discussion

Preliminary study:

Prior to the main study, a preliminary study was conducted using 3 animals of each sex during the quarantine/acclimatization period. The dose level was 2000 mg/kg bw, in accordance with the toxicity study guidelines. No deaths occurred at this dose level. Based on these results, 2000 mg/kg bw was set as a high dose level and 2 other dose levels were set at 1000 and 500 mg/kg bw (i.e. ratio 2).

Effect levels

Sex:

male/female

Dose descriptor:

LD0

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No deaths occurred in either sex in any dose group. The lethal dose was estimated more than 2000 mg/kg bw.

Clinical signs:

other: No abnormalities were observed in any animals.

Gross pathology:

No abnormalities were found in the external appearance or the tissue/organs in the cranial, thoracic and abdominal cavities in any of the animals.

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: Japan

Conclusions:

When L-leucine was administered once by gavage to rats, the toxicity was suggested to be very low.

Executive summary:

A single dos toxicity study of L-leucine by oral administration was conducted in Sprague-Dawley rats [Crj:CD(SD), 6 animals / sex / dose] at dose levels of 0 (5% gummi arabicum solution), 500, 1000 and 2000 mg/kg bw. No deaths occured in either sex in any dose group. No abnormal clinical signs were observed in any animals. The body weight changes of both sexes in all dose groups were comparable to the control group. The necropsy reveales no abnormalities in any animal.

The toxicity of L-leucine upon single oral administration was found to be very low. The lethal dose was estimated > 2000 mg/kg bw.