L-tryptophan

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2006-11-27 to 2007-02-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline 423 (adopted 2001)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

L-tryptophan

EC Number:

200-795-6

EC Name:

L-tryptophan

Cas Number:

73-22-3

Molecular formula:

C11H12N2O2

IUPAC Name:

L-tryptophan

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

Strain: Hsd:Sprague-Dawley SD
Source: Harlan Italy S.r.l.
Body weight: 176 – 200 g
Age: ca. 6 - 8 weeks
Acclimatisation period: at least 5 days
Housing: in groups of 3, polycarbonate cages, equipped with a stainless steel mesh lid and floor
Diet: laboratory rodent diet (4 RF 18) ad libitum throughout the study except for an overnight fast prior to dosing and a period of approximately 4 hours after dosing
Water: ad libitum

Environmental conditions
Temperature (°C): 22 ± 2
Relative humidity (%): 55 ± 15
Photoperiod (hrs dark / hrs light): 12 / 12 by fluorescent tubes
Air changes (per hr): 15-20

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

0.5%

Details on oral exposure:

The test item was formulated for dosing by suspension in 0.5% aqueous solution of carboxymethylcellulose to give a concentration of 200 mg/mL.
Dose volume: 10 mL/kg bw

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Two groups with 3 females each were tested

Control animals:

no

Details on study design:

Animals were fasted overnight prior to dosing and food was made available approximately 4 hours after dosing.
Mortality and morbidity: Throughout the study all animals were checked twice daily.
Clinical signs: Animals were observed for clinical signs immediately upon dosing, approximately 30 min, 2 and 4 hours after dosing and daily thereafter for a total of 14 days.
Body weight: All animals were weighed at allocation to the study (day -1), immediately prior to dosing (day 1) and on days 2, 8 and 15.

All animals were killed on day 15 and were subjected to a gross necropsy examination for both external and internal abnormalities. The cranial, thoracic and abdominal cavities were opened to allow examination of their contents. Larger organs were sectioned. Both the stomach and representative sections of the gastro-intestinal tract were opened for examination of the mucosal surfaces.

Statistics:

not further specified

Results and discussion

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

None

Clinical signs:

other: In trial 1, clinical signs were limited to piloerection seen on the day of dosing at the 2 and 4 hour post-dose observations. In trial 2, piloerection, hunched posture and reduced activity were observed in the animals on the day of dosing. Complete recove

Gross pathology:

No abnormalities found at termination

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute oral toxicity of L-tryptophan feed grade was investigated in a GLP study according to OECD guideline 423. Two groups of 3 female Sprague-Dawley rats were dosed with 2000 mg/kg bw and observed for a period of 14 days. No mortality occurred. In trial 1, clinical signs were limited to piloerection seen on the day of dosing at the 2 and 4 hour post-dose observations. In trial 2, piloerection, hunched posture and reduced activity were observed in the animals on the day of dosing. Complete recovery occurred by day 2. Changes in body weight were within the expected range for this strain and age of animals. No abnormalities were observed at necropsy examination at termination of the study. From this study a LD50 value of > 2000 mg/kg bw can be derived.