L-tryptophan

Endpoint summary

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

Study period:

2006-12-07 to 2007-02-09

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline 404 (adopted 2002)

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Source: Harlan Italy s.r.l.
Weight: ca. 2000 g
Age: 9 – 11 weeks
Acclimatisation period: at least 10 days
Housing: individually in stainless steel cages equipped with grid floor
Diet: STANRAB (P) SQC ad libitum
Water: ad libitum

Environmental conditions:
Temperature (°C): 19 ± 2
Relative humidity (%): 55 ± 15
Photoperiod (hrs dark / hrs light): 12 / 12 by fluorescent tubes
Air changes (per hr): 15-20

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

water

Controls:

other: untreated skin sites of the same animal

Amount / concentration applied:

TEST MATERIAL
Amount applied: 0.5 g reduced to a paste with 0.1 mL sterile water

Duration of treatment / exposure:

4 h

Observation period:

up to 72 h

Number of animals:

3

Details on study design:

TEST SITE
Area of exposure: dorsolateral part of the trunk
Type of wrap: 2.5 cm x 2.5 cm square gauze fixed by a strip of synthetic film and elastic adhesive bandage

REMOVAL OF TEST SUBSTANCE
Washing with water
Time after start of exposure: 4 h

SCORING SYSTEM
According to guideline

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 24 - 72 h

Score:

0

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute dermal irritation of L-tryptophan was investigated with rabbits in a GLP study according to OECD guideline 404. There was no indication of a systemic effect of treatment. Changes in body weight were not remarkable. No irritation was apparent following a 4 h period of exposure to the test item. Therefore, L-tryptophan can be classified as not skin irritating.

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

Study period:

2007-02-13 to 2007-02-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline 405 (adopted 2002)

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

Source: Harlan Italy s.r.l.
Weight: ca. 2000 g
Age: 9 – 11 weeks
Acclimatisation period: at least 10 days
Housing: individually in stainless steel cages equipped with grid floor
Diet: STANRAB (P) SQC ad libitum
Water: ad libitum

Environmental conditions:
Temperature (°C): 19 ± 2
Relative humidity (%): 55 ± 15
Photoperiod (hrs dark / hrs light): 12 / 12 by fluorescent tubes
Air changes (per hr): 15-20

Vehicle:

unchanged (no vehicle)

Controls:

other: untreated eye of the same animal

Amount / concentration applied:

TEST MATERIAL
Amount applied: 100 mg

Duration of treatment / exposure:

Single application

Observation period (in vivo):

up to 72 h

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
No rinsing

SCORING SYSTEM
According to guideline

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 24 - 72 h

Score:

0

Irritant / corrosive response data:

Slight redness, chemosis and discharge (scores of 1) were observed in the 3 animals at the 1 h examination. The ocular reactions were reversible in all animals within 24 h after application.

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute eye irritation of L-tryptophan was investigated with rabbits in a GLP study according to OECD guideline 405. There was no indication of a systemic effect of treatment. Changes in body weight were not remarkable. A slight irritation was observed at the 1 h examination in all animals, but recovery occurred at the 24 h examination. Therefore, L-tryptophan can be classified as not eye irritating.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The acute dermal irritation of L-tryptophan was investigated with rabbits in a GLP study according to OECD guideline 404. There was no indication of a systemic effect of treatment. Changes in body weight were not remarkable. No irritation was apparent following a 4 h period of exposure to the test item. Therefore, L-tryptophan can be classified as not skin irritating.

The acute eye irritation of L-tryptophan was investigated with rabbits in a GLP study according to OECD guideline 405. There was no indication of a systemic effect of treatment. Changes in body weight were not remarkable. A slight irritation was observed at the 1 h examination in all animals, but recovery occurred at the 24 h examination. Therefore, L-tryptophan can be classified as not eye irritating.

Justification for classification or non-classification

Due to negative results in OECD guideline studies regarding irritation to skin and irritation to eyes, no classification according to EU and GHS criteria is required.