Ethyl L-threoninate

Endpoint summary

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April 24, 2000 - May 30, 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Deviations:

no

Principles of method if other than guideline:

NA

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): Threonineethylester
- Analytical purity: 97%
- Purity test date: No data
- Lot/batch No.: 142-576-6
- Expiration date of the lot/batch: No data
- Stability under test conditions: Considered to be stable during testing
- Storage condition of test material: Frozen

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing:
- Preliminary purification step (if any):
- Preparation of a nanomaterial dispersion (incl. dilution):
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid:

FORM AS APPLIED IN THE TEST (if different from that of starting material)

OTHER SPECIFICS
- measurement of pH, osmolality, and precipitate in the culture medium to which the test chemical is added:
- other information:

Species:

rat

Strain:

Wistar

Remarks:

Crl:Wl(Glx/BRL/han)BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd, Margate
- Age at study initiation: 9 to 11 weeks old
- Weight at study initiation: 285-319g (males), 178-194g (females)
- Fasting period before study: overnight prior to dosing
- Housing: suspended stainless steel mesh cages
- Diet (e.g. ad libitum): ad libitum, except overnight prior to dosing and three hours after dosing
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 7 or 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25°C
- Humidity (%): 40-70 % RH
- Air changes (per hr): 12 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours daily with flurorescent strip-lights

IN-LIFE DATES: From 11 April or 9 May 200 to 30 May 2000

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

Purified water from on site Elgastat purifier.

Details on oral exposure:

VEHICLE
- Concentration in vehicle: Dispersed in purified water to reach 10/20 mL/kg bw
- Justification for choice of vehicle: solubility

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg (males) and 20 mL/kg (females)

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Dose selection followed the Acute Toxic Class procedure detailed in EC and OECD guidelines.

Doses:

2000 mg/kg

No. of animals per sex per dose:

3 males and 3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations at least daily, weighing on Day -1, 1, 8 and 15.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,necropsy

Statistics:

NA

Preliminary study:

NA

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality was observed

Clinical signs:

other: No clinical signs was observed

Gross pathology:

No macroscopic changes were observed for animals killed on Day 15.

Other findings:

- Organ weights: Not performed
- Histopathology: Not performed
- Potential target organs: None

None

Interpretation of results:

not classified

Conclusions:

The acute oral toxicity of L-TEE was assessed in rats following a single administration of L-TEE. The study was performed in compliance with OECD guideline 423 and ECC guideline B1 tris. The acute oral median lethal dose (LD50) of L-TEE was estimated to be greater than 2000 mg/kg bw.

Executive summary:

This study was conducted to assess the acute toxicity of L-TEE following a single oral administration of 2000 kg/kg bw. It was designed to meet the known requirements of the testing guidelines ECC (B1 tris); OECD (423) and US EPA OPPTS 870.1100.

Groups of three male or three female fasted rats were given L-TEE as a single dose on Day 1 by oral gavage at a dose level of 2000 mg/kg. L-TEE was dispersed in purified water and administered at a dose volume of 10 or 20 mL/kg.

All animals were killed on Day 15 and subsequently underwent a full necropsy. There were no deaths. No clinical signs of reaction to treatment were noted and there were no effects on body weight gain. Macroscopic examination of the animals revealed no abnormalities.

Following a single administration of L-TEE to rats, the acute median lethal oral dose was found to exceed 2000 mg/kg.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

This study was performed is compliance with GLP standards and testing guidelines. The study has klimisch score 1.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 5, 2007 - October 19, 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Minor deviations in temperature, humidity and oxygen concentration were observed during the study period but these deviations did not affect the integrity of the study.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

temperature, humidity and oxygen concentration

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

temperature, humidity and oxygen concentration

Principles of method if other than guideline:

NA

GLP compliance:

yes (incl. QA statement)

Test type:

fixed concentration procedure

Limit test:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: 0706H013
- Expiration date of the lot/batch: 1 February 2009
- Purity test date: 2 April 2007


STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: 10 - 30°C
- Stability under test conditions: stable under the chosen method of aerosol generation


TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: test article was prepared as a solution in purified (double distilled) water.
- Final dilution of a dissolved solid, stock liquid or gel: 400 mg/mL

FORM AS APPLIED IN THE TEST (if different from that of starting material)

INFORMATION ON NANOMATERIALS
- Particle size & distribution: Mass Median Aerodynamic Diameter 2.25 µm

Species:

rat

Strain:

Wistar

Remarks:

HsdRccHan: WIST

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Limited, Bicester
- Age at study initiation: 8 to 10 weeks
- Weight at study initiation: mean for males 208g, mean for females 171g.
- Fasting period before study: while retained for exposure, animals did not have access to food and water
- Housing: single room
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 10 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18.3 to 19.5°C
- Humidity (%): 70.1 to 75.0 %
- Air changes (per hr): 12 air changes/hour
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: September 25, 2007 to October 19, 2007.

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

other: The test article was prepared as a solution in purified (double-destilled) water as it was not possible to produce a respirable aerosol from the solid test article.

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: flow-through exposure chamber
- Exposure chamber volume: 40L
- Method of holding animals in test chamber: Inhalation chambers
- Source and rate of air: no data
- Method of conditioning air: no data
- System of generating particulates/aerosols: Hospital Clinical nebuliser
- Method of particle size determination: gravimetrically
- Treatment of exhaust air: no data
- Temperature, humidity, pressure in air chamber: 18.9°C, 72.4 %, 20.5 % (v/v)

TEST ATMOSPHERE
- Brief description of analytical method used: the aerosol was sampled approx. twice hourly during the animal exposure.
- Samples taken from breathing zone: yes

VEHICLE
- Composition of vehicle (if applicable): purified (double-distilled) water
- Concentration of test material in vehicle (if applicable): 400 mg/mL
- Justification of choice of vehicle: solubility


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: determined gravimetrically, and sampled using a Marple Andersen 298 Cascade Impactor
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 2.32µm / 2.41

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: NA

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

The aerosol concentration ranged between 5.42 and 6.82mg/L. The mean concentration was 6.16mg/L.

No. of animals per sex per dose:

5 males and 5 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations daily, weighing on Day 1, 2, 3, 8 and 15.
- Necropsy of survivors performed: yes (all animals)
- Other examinations performed: clinical signs, body weight,necropsy

Statistics:

Report generation and statistal analysis: Costar/Office 97

Preliminary study:

None

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5 mg/L air

Exp. duration:

4 h

Mortality:

No animals died

Clinical signs:

other: Clinical signs of reaction to treatment were confined to wet fur, staining of the snout and unkempt appearance. These signs were present during exposure and lasted up to Day 3. Chromodacryorrhoea was also noted in two males during the exposure.

Body weight:

All rats achieved body weight gains during the first and second weeks of the study.

Gross pathology:

No macroscopic changes were observed at necropsy.

Other findings:

- Organ weights: not performed
- Histopathology: not performed
- Potential target organs: None

None

Interpretation of results:

GHS criteria not met

Conclusions:

The acute inhalation toxicity of L-TEE was assessed in rats using a single exposure via inhalation (nose only) in an exposure chamber of approximate volume 40L. The study was performed in accordance with testing guidelines EC (method B2) and OECD (403).

The acute median lethal dose level (LC50) was found to exceed 5 mg/L.

Executive summary:

L-TEE formulation was administered as a single exposure via inhalation (nose only) in an exposure chamber of approximate volume 40 L. A limit test was performed using five males and five females exposed for four hours to an exposure concentration of approximately 5.04mg/L. All animals were killed on Day 15 and subsequently underwent a full necropsy.

No animal died. Clinical signs of reaction to treatment were confined to wet fur, staining of the snout and unkempt appearance. These signs were present during exposure and lasted up to Day 3. Chromodacryorrhoea was also noted in two males during the exposure.

Recovery, as judged by external appearance and behaviour, was complete by Day 4. All rats achieved body weight gains during the first and second weeks of the study. No macroscopic changes were observed at necropsy.

The acute median lethal dose level (LC50) was found to exceed 5 mg/L.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

5 mg/m³ air

Quality of whole database:

This study was performed is compliance with GLP standards and testing guidelines. The study has klimisch 1.

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The acute toxicity of L-TEE was assessed in rats following using oral and inhalational route of dosing.

The acute oral toxicity of L-TEE was assessed in rats following a single administration of L-TEE. The study was performed in compliance with OECD guideline 423 and ECC guideline B1 tris. The acute oral median lethal dose (LD50) of L-TEE was estimated to be greater than 2000 mg/kg bw.

The acute inhalation toxicity of L-TEE was assessed in rats using a single exposure via inhalation (nose only) in an exposure chamber of approximate volume 40L. The study was performed in accordance with testing guidelines EC (method B2) and OECD (403). The acute median lethal dose level (LC50) was found to exceed 5 mg/L.

Justification for selection of acute toxicity – oral endpoint
The study is a key study.

Justification for selection of acute toxicity – inhalation endpoint
This study is a key study

Justification for classification or non-classification

L-TEE was shown to have low acute toxicity by the oral route i.e. LD50 greater than 2000 mg/kg bw and by the inhalational route i.e. LC50 greater than 5 mg/L. Based on these results, L-TEE is not hazardous and is not classified according to GHS and DSD-DPD.