Amitrole

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09-23 October 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

GLP study performed according to the OECD Guideline 402 with minor deviations: temperature and relative humidity recorded in the animal room were sometimes outside of the target ranges

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

24 February 1987

Deviations:

yes

Remarks:

temperature and relative humidity were sometimes outside of the target ranges

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Version / remarks:

31 July 1992

Deviations:

yes

Remarks:

temperature and relative humidity were sometimes outside of the target ranges

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

12 January 2001

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Amitrole

EC Number:

200-521-5

EC Name:

Amitrole

Cas Number:

61-82-5

Molecular formula:

C2H4N4

IUPAC Name:

amitrole

Test material form:

solid: flakes

Remarks:

whitish flakes

Details on test material:

- Expiration date of the lot/batch: 18 November 2001
- Purity test date: 27 January 2000
- Storage condition of test material: At room temperature protected from light and humidity; in its original packaging
- pH at the concentration of 10% in purified water: 7

Specific details on test material used for the study:

- Date of receipt: 14 August 2001
- Name as cited in the report: AMITROLE

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: On the day of treatment, the test item was ground to a fine powder using a mortar and pestle.

FORM AS APPLIED IN THE TEST (if different from that of starting material): Purified water (prepared at CIT by reverse osmosis) was used in order to moisten the test item and ensure a good contact with the skin.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Remarks:

ICO: OFA-SD (IOPS Caw)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, L'Arbresle, France
- Females (if applicable) nulliparous and non-pregnant: Yes
- Age at study initiation: ca. 8 weeks old
- Weight at study initiation: 248 ± 9 g for males; 214 ± 10 g for females
- Housing: During the treatment period, the animals were housed individually in polycarbonate cages with stainless steel lid.
- Diet (e.g. ad libitum): A04 C pelleted diet (UAR, Villemoisson, Epinay-sur-Orge, France), ad libitum
- Water (e.g. ad libitum): Drinking water filtered by a FG Millipore membrane (0.22 micron), ad libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 2°C
- Humidity: 30-70%
- Air changes: ca. 12/hour
- Photoperiod: 12 hours dark / 12 hours light

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: Clipped dorsal area (i.e. approximately 5 cm x 6 cm for the females and 5 cm x 7 cm for the males)
- % coverage: 10% of the total body surface
- Type of wrap if used: Test item ground to a fine powder was placed on a hydrophilic gauze pad pre-moistened with 2 mL of water and then applied to an area of the skin. The test item and the gauze pad were held in contact with the skin for 24 hours by means of an adhesive hypoallergenic aerated semi-occlusive dressing and a restraining bandage. This dressing prevented ingestion of the test item by the animal.

REMOVAL OF TEST SUBSTANCE
- On removal of the dressing, any residual test item was removed using a dry gauze pad.
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg bw

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Five

Control animals:

other: historical control

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Animals were observed frequently during the hours following administration of the test item, for detection of possible treatment-related clinical signs. Thereafter, observation of the animals was made at least once a day until Day 15. Type, time of onset and duration of clinical signs were recorded for each animal individually. Animals were weighed individually just before administration of the test item on Day 1 and then on Days 8 and 15. The body weight gain of the treated animals was compared to that of CIT control animals with a similar initial body weight.
- Necropsy of survivors performed: Yes, on Day 15, all animals were killed by carbon dioxide asphyxiation. All study animals were subjected to a macroscopic examination as soon as possible after death. After opening the thoracic and abdominal cavities, a macroscopic examination of the main organs (digestive tract, heart, kidneys, liver, lungs, pancreas, spleen and any other organs with obvious abnormalities) was performed. No organ samples were taken.
- Other examinations performed: From Day 2, any local cutaneous reaction was recorded.

Statistics:

None

Results and discussion

Preliminary study:

Not applicable

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

no indication of skin irritation up to the relevant limit dose level

Mortality:

No deaths were observed during the study.

Clinical signs:

other: No clinical signs of toxicity were observed during the study.

Gross pathology:

No apparent abnormalities were observed at necropsy in any animal.

Other findings:

No cutaneous reactions were observed during the study.

Any other information on results incl. tables

None

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the test conditions, the dermal LD50 of the test substance is higher than 2000 mg/kg bw in rats as it is the maximum dose tested and is expected to be higher than 5000 mg/kg bw, therefore it is not classified according to the Annex VI of the Regulation (EC) No. 1272/2008 (CLP) and to the GHS.

Executive summary:

In an acute dermal toxicity study performed according to the OECD Guideline 402 and in compliance with GLP, a single dose of 2000 mg/kg bw of the test substance was applied to the skin of 5 male and 5 female Sprague-Dawley rats under semi-occlusive dressings for 24 hours. Animals were then observed for mortality, clinical signs and body weight changes for 14 days, and were all sacrificed for macroscopic examinations.

No clinical signs and no deaths were observed during the study. No cutaneous reactions were observed. A reduced weight gain or a slight body weight loss was seen in 3/5 females between Day 1 and Day 8 and in 2/5 females during the second week of the observation period. The body weight gain of the other treated animals was similar to that of historical control animals. No apparent abnormalities were observed at necropsy in any animal.

Rat dermal LD50 >2000 mg/kg bw.

Under the test conditions, the dermal LD50 of the test substance is higher than 2000 mg/kg bw in rats as it is the maximum dose tested and is expected to be higher than 5000 mg/kg bw, therefore it is not classified according to the Annex VI of the Regulation (EC) No. 1272/2008 (CLP) and to the GHS.