mecoprop-P (ISO); (R)-2-(4-chloro-2-methylphenoxy)propionic acid

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 January 1990 to 25 March 1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

1987

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPP 81-2 (Acute Dermal Toxicity)

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

(R)-2-(4-chloro-2-methylphenoxy)propionic acid

EC Number:

240-539-0

EC Name:

(R)-2-(4-chloro-2-methylphenoxy)propionic acid

Cas Number:

16484-77-8

Molecular formula:

C10H11ClO3

IUPAC Name:

(R)-2-(4-chloro-2-methylphenoxy)propionic acid

Test material form:

solid: flakes

Remarks:

Brown coloured hard flakes

Details on test material:

- Storage conditions: Room temperature protected from light.

Test animals

Species:

rat

Strain:

other: CD strain (remote Sprague-Dawley origin)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Animals were approximately eight weeks old on arrival. On the day prior to dosing the animals were approximately ten weeks old.
- Weight at study initiation: Bodyweight was recorded on the day prior to dosing and was in the range 246 - 264 g for males and 216 - 237 g for females.
- Housing: The animals were housed in stainless steel grid cages measuring 54 x 33 x 20 cm. The grid floors ensured rapid removal of waste material to undertrays which were cleaned as necessary. Five animals of the same sex were housed in each cage. The cages were suspended in mobile stainless steel racks. On completion of dosing, the animals were accommodated individually in cages measuring 45 x 28 x 20 cm. The dressings were removed 24 hours after administration. The animals were then returned to their original cages.
- Diet: A commercially-available complete pelleted rodent diet was fed without restriction. The diet contained no added antibiotic or other chemotherapeutic or prophylactic treatment.
- Water: Animals had free access to tap water supplied in a single bottle per cage and re-filled as required. The water was supplied by the East Anglian Water Company.
- Acclimation period: At least 6 days.
- Microbiological status when known: The animals had been bred under barriered conditions and travelled from the supplier to the animal-holding room in sealed boxes with filter protected air-vents

ENVIRONMENTAL CONDITIONS
- Temperature: Target value 21 °C (18 to 25 °C)
- Humidity: Target value 55 % relative humidity (40 to 70 %)
- Air changes: All rooms were kept at slight positive pressure relative to the outside and each had its own filtered air supply giving approximately 15 complete air changes per hour without re-circulation.
- Photoperiod: Electric time-switches regulated a lighting cycle of 12 hours of artificial light per day.

IN-LIFE DATES
From: 1 March 1990
To: 15 March 1990

Administration / exposure

Type of coverage:

occlusive

Vehicle:

water

Details on dermal exposure:

TEST SITE
- Area of exposure: The dorsum between the limb-girdles was clipped free of hair as close to the skin as possible using Oster small animal clippers. The exposed application site of each rat was examined before the animal was allocated to study.
- Type of wrap if used: The gauze patch was placed on the closely-clipped dorsum and was occluded with aluminium foil. The foil was kept in place and protected by a bandage of waterproof plaster wrapped twice around the trunk of the body with sufficient tension to ensure the dose remained securely in place.

REMOVAL OF TEST SUBSTANCE
- Washing: The dermal site was gently wiped with wet disposable towels to remove residual test material.
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied: The dose was determined for each animal according to its bodyweight on the morning of dosing. The dosage was calculated and expressed gravimetrically in terms of the material as received.
- For solids, paste formed: No. The test material was placed on a gauze patch and moistened by application of 0.2 mL distilled water immediately before dosing. This was intended to ensure good contact between the test material and the skin surface and to simulate the maximum adverse conditions of the product in use.

VEHICLE
- Amount(s) applied: 0.2 mL

Duration of exposure:

24 hours

Doses:

2 000 mg/kg

No. of animals per sex per dose:

5 animals per sex per dose

Control animals:

not required

Details on study design:

- Duration of observation period following administration: The test was terminated on Day 15
- Frequency of observations and weighing: Three separate inspections were made during the first hour after administration and two further inspections during the remainder of Day 1. From Day 2 onwards, the animals were inspected twice daily (morning and afternoon). Each dermal application site was examined at the morning observation. The type, time of onset and duration of reactions to treatment were recorded. The bodyweight of each animal was recorded on the day before dosing and on Days 1, 8 and 15.
- Necropsy of survivors performed: Yes. Animals were killed at termination of the study by carbon dioxide inhalation. All rats were weighed and thoroughly examined at necropsy for abnormality of tissues or organs. All body cavities were opened, larger organs were sectioned and the gastro-intestinal tract was opened at intervals for examination of the mucosal surfaces. Any abnormalities were described or the normal appearance of major organs was confirmed
- Other examinations performed: Each dermal application site was examined in situ, and in macroscopic section to obtain more information on dermal effects of treatment.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

There was no death.

Clinical signs:

other: There was no systemic or local sign of reaction to treatment.

Gross pathology:

Necropsy, on Day 15, revealed no significant macroscopic lesion.

Applicant's summary and conclusion

Interpretation of results:

other: Not classified according to EU criteria.

Conclusions:

Under the conditions of this study, the acute percutaneous median lethal dosage (LD50) of the test material was greater than 2 000 mg/kg.

Executive summary:

The acute percutaneous toxicity of the test material was investigated in a group of five male and five female CD rats in accordance with the standardised guideline OECD 402 and in compliance with GLP.

The test material was applied to the closely-clipped dorsum of each animal on Day 1 at a limit dosage of 2 000 mg/kg, and was covered by an occlusive dressing for 24 hours. Systemic or local signs of reaction to treatment were recorded during a subsequent 14-day period of observation. The animals were killed on Day 15 and subjected to necropsy.

There was no death. There was no systemic or local sign of reaction to treatment. The animals achieved expected bodyweight gains. Necropsy, on Day 15, revealed no significant macroscopic lesion.

Under the conditions of this study, the acute percutaneous median lethal dosage (LD50) of the test material was greater than 2 000 mg/kg.