L-cysteine

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

L-cysteine

EC Number:

200-158-2

EC Name:

L-cysteine

Cas Number:

52-90-4

Molecular formula:

C3H7NO2S

IUPAC Name:

L-cysteine

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Name: L-Cysteine
Chemical Name: L-( +)-Cysteine
CAS No.: 52-90-4
Batch No.: 12030506
Physical State: solid
Colour: white
Molecular Weight: 121.1
pH: 4.5-6
Storage Conditions: 2-8°C, protected from light

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

other: aqua ad injectionem

Details on dermal exposure:

Species/strain: healthy rats, WISTAR rats Crl: WI(Han) (full barrier)
Source: Charles River, 97633 Sulzfeld, Germany
Sex: male and female
Number of animals: 5 male and 5 female
Age at the beginning of the study: males: 8 - 9 weeks old; females: 12- 14 weeks old
Body weight on the day of administration: males: 233 - 257 g; females: 210-217 g.

Full barrier in an air-conditioned room
Temperature: 22 ± 3 °C
Relative humidity: 55± 10%
Artificial light, sequence being 12 hours light, 12 hours dark
Air change: 10 x/ hour
Free access to Altromin 1324 maintenance diet for rats and mice (lot no. 0906) Free access to tap water, sulphur acidified to a pH value of approximately 2.8 (drinking water, municipal residue control, microbiological controls at regular intervals)
The animals were kept individually in IVC cages, type III H, polysulphone cages on Altromin saw fibre bedding (lot no. 300512). Adequate acclimatisation period (at least five days) under laboratory conditions

Duration of exposure:

24 h

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

The animals were marked for individual identification by tail painting. Approximately 24 hours before the test, the fur was removed from the dorsal area of the trunk using an electric clipper. Care was taken to avoid abrading the skin, and only animals with healthy intact skin were used.
No less than 10% of the body surface was cleared for the application. Prior to the application a detailed clinical observation was made of all animals.

The test item was applied at a single dose, uniformly over an area which was approximately 10% of the total body surface. The test item was held in contact with the skin by a dressing throughout a 24-hour period. The dressing consisted of a gauze-dressing and non-irritating tape and was fixed with an additional dressing in a suitable manner.

Results and discussion

Effect levels

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: The test item showed no signs of acute dermal toxicity but signs of dermal irritation after a single dose application.

Gross pathology:

With the exception of acute injection of blood vessels in the abdominal region, which is due to the euthanasia injection, no specific gross pathological changes were recorded for any animal.

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The substance is not toxic to rats under the conditions of this study.

Executive summary:

An actute dermal toxicity study was performed with L-Cysteine according to OECD Guideline 402. The substance was administered at a single dose, uniformly over an area which was approximately 10% of the total body surface. The test item was held in contact with the skin by a dressing throughout a 24-hour period. The dressing consisted of a gauze-dressing and non-irritating tape. Under the conditions of the present study, single dermal application of the test item L-Cysteine to rats at a dose of 2000 mglkg body weight was associated with neither mortality nor signs of toxicity but signs of irritation. The dermal LD5O was determined to be > 2000 mg L-Cysteine /kg body weight. No clear signs of toxicity were observed.