DL-alanine

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1971

Report date:

1971

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

No OECD testing guideline was available at that time - study was generally carried out as a limit test as described in OECD 403 but at a higher dose level than 5 g/kg bw, and a control group was also included

GLP compliance:

no

Remarks:

GLP did not exist at that time

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

DL-alanine

EC Number:

206-126-4

EC Name:

DL-alanine

Cas Number:

302-72-7

Molecular formula:

C3H7NO2

IUPAC Name:

DL-alanine

Test material form:

not specified

Test animals

Species:

rat

Strain:

other: CFY strain

Sex:

male/female

Details on test animals or test system and environmental conditions:

The rats of the CFY strain were obtained from Carworth Europe, Alconbury, Huntingdon. At the time of dosing they were in the weight range of 62 to 123 g. Each animal was deprived of food for a period of 20 hours prior to dosing, after which food was withheld for a further four hours. Throughout the subsequent observation period of two weeks, they were caged in groups according to sex and dosage.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

The test substances were prepared as 30% solution in water or as 30% suspension in 1% methyl celluloe. Since DL-alanine is water soluble the application as a solution in water is likely.

Details on oral exposure:

The twenty five amino acids were prepared as 30% solutions in water or as 30% suspensions in 1% methyl cellulose and administered by gastric intubation at a maximum dosage volume of 53.3 mL/kg bodyweight. This gave a maximum practical dose of 16 g amino acid /kg body weight. Rats dosed with the vehicle alone served as controls. Dosage volumes in excess of 20 mL/kg were given in divided doses at two hourly intervals.

Doses:

16 g amino acid / kg bodyweight

No. of animals per sex per dose:

Ten rats (five males and five females) were dosed at 16 g/kg bodyweight.

Control animals:

yes

Details on study design:

The test animals were deprived of food for a period of 20 hours prior to dosing, after which food was withheld for a further four hours. Throughout the subsequent observation period of two weeks, they were caged in groups according to sex and dosage. The test substance was prepared as a 30% solution and administered by gastric intubation at a maximum dosage volume of 53.3 ml/kg bodyweight. This gave a maximum practical dose of 16 g amino acid /kg body weight. Rats dosed with the vehicle alone served as controls. Dosage volumes in excess of 20 ml/kg were given in divided doses at two hourly intervals.
During the observation period, a record was kept of all mortalities and signs of toxicity. During the observation period (two weeks), a record was kept of all mortalities and signs of toxicity. All rats that died were examined macroscopically in an attempt to identify the target organs, and animals surviving terminally were similarly examined to detect possible residual damage.
Assessment of degree of recovery from the initial toxic action of the product was made subjectively from appearance and behaviour of the animals and, more objectively, by weekly checks on bodyweight.

Statistics:

Not applicable.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 16 000 mg/kg bw

Based on:

test mat.

Mortality:

One female rat died seven hours after dosing. Autopsy did not reveal any specific cause of death.

Clinical signs:

other: none

Gross pathology:

No findings

Other findings:

Lethargic behaviour was the only sign of reaction to treatment.

Applicant's summary and conclusion

Interpretation of results:

other: EU GHS criteria not met

Conclusions:

The LD50 of D,L-alanine for acute oral toxicity in rats was determined to be > 16 g/kg bw.

Executive summary:

In an acute oral toxicity study, ten CFY rats (five males and five females) were given a single dose of D,L-alanine at 16 g/kg bw. Lethargic behaviour was the only sign of reaction to treatment. One female was found dead 7 h after treatment. Recovery of survivors, as judged by external appearance and behaviour, was apparently complete within 24 hours. This observation was substantiated by normal bodyweight increases, except for a slight depression amongst treated females during the first week. The median lethal oral dose (LD50) was greater than 16 g/kg bodyweight.