L-tryptophan

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008-03-12 to 2008-04-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline 403 (adopted 1981)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

traditional inhalation LC50 study

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Deviations:

no

GLP compliance:

yes

Test type:

standard acute 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:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
Source: Charles River Deutschland GmbH, Sulzfeld, Germany
Age at study initiation: 8 – 9 weeks at time of administration
Body weight: 229 - 322 g before exposure
Housing: single caging in Makrolon type III cages; wire mesh lids
Diet: Ssniff R/M-H maintenance diet ad libitum
Water: tap water, ad libitum
Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
Temperature (°C): 21.7-24.3
Humidity (%): 46.2-64.9
Air changes (per hr): 12
Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
Exposure apparatus: exposure chamber from TSE, Technical & Scientific Equipment GmbH, Germany
Exposure chamber volume: 19 L
System of dust generating: dust generator Technical & Scientific Equipment GmbH, Germany
Method of particle size determination: cascade impactor
Rate of air: 700 L/h
MMAD: 3.1 um

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Measurement by gravimetric analysis. Dust was collected 12 times during exposure period. The exact amount of collected air was measured by a gas meter.

Duration of exposure:

4 h

Concentrations:

Target concentration: 5 mg/L
Actual concentration of the dust: 5.17 mg/L

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

Duration of observation period following administration: 14 days
Frequency of observations: 1 - 6 hours after the start of exposure and daily thereafter
Frequency of weighing: day 0 and on days 7 and 14 following administration
Necropsy of survivors performed: yes
Other examinations performed: clinical signs, body weight

Statistics:

Means and standard deviations of each test group were calculated for body weight and body weight gain. Median was calculated for environmental condition in the animal room. The particle size distribution was statistically evaluated based on probit analysis. As a limit test was performed, no calculation of the LC50 was possible.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.17 mg/L air

Exp. duration:

4 h

Mortality:

No mortality.

Clinical signs:

other: All animals were normal during the whole 14-day observation period

Body weight:

Mean body weights: Prior to study: 322 g (males) and 229 g (females); End of study: 407 g (males) and 252 g (females)
Mean weight gain: days 0-7: 38.4 g (males) and 5.4 g (females); days 7-14: 45.8 g (males) and 18.0 g (females)
Two females lost weight in the first week after exposure

Gross pathology:

Nothing abnormal was seen in any of the animals

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

L-tryptophan feed grade was tested in a GLP study according to OECD guideline 403. The 4h-inhalation exposure of male and female Sprague-Dawley rats at a concentration of 5.17 mg/L gave no indications for adverse effects. Therefore, the 4h-LC50 is greater than 5.17 mg/L air.