Diquat dibromide

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Feb 1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to 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:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

1987

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Version / remarks:

1998

Test guideline 3

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

1992

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Diquat dibromide

EC Number:

201-579-4

EC Name:

Diquat dibromide

Cas Number:

85-00-7

Molecular formula:

C12H12N2.2Br

IUPAC Name:

1,1'-ethylene 2,2'-bipyridyldiylium dibromide

Constituent 2

Reference substance name:

Water

EC Number:

231-791-2

EC Name:

Water

Cas Number:

7732-18-5

Molecular formula:

H2O

IUPAC Name:

water

Test material form:

liquid

Test animals

Species:

rat

Strain:

Wistar

Remarks:

Alpk:APfSD

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 9.5 weeks for males, 8.5 weeks for females
- Weight at study initiation: 295 - 337 g for males, 196 - 228 g for females
- Housing: Individually in suspended stainless steel and polycarbonate cages (each cage divided into 2 separate compartments)
- Diet: Porton Combined Diet, ad libitum
- Water: Drinking water, ad libitum
- Acclimation period: At least 6 day

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 15 - 24
- Humidity (%): 50 ± 10
- Air changes (per hr): 20 - 30
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE dates: From Feb 1990 To: Feb 1990

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

16 - 32 hours before application, the hair was removed using veterinary clippers, from an area approximately 10 cm x 5 cm on the dorso-lumbar region of each rat. The undiluted test substance was applied to the shorn backs at a nominal rate of 2 mL/kg bw, under occlusive dressings for a period of 24 hours. At the end of the 24 hour application period, the dressings were removed and any residual test substance was removed from the skin using cotton wool swabs and clean warm water and the skin dried with tissue paper.

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

EXPERIMENTAL DESIGN
A single administration was performed by the dermal route and was followed by a 15-day observation period.

CLINICAL OBSERVATIONS
The animals were examined for any signs of systemic toxicity once between 1 and 4 hours after application and then once daily for systemic toxicity and skin irritation up to day 15.

MEASUREMENT OF BODY WEIGHT
Body weights were recorded immediately before application of the test substance (day 1) and on days 3, 5, 8 and 15.

POST MORTEM INVESTIGATIONS
At the end of the scheduled observation period, all animals were necropsied and examined macroscopically.

Statistics:

No statistical analysis was used (limit test, no mortalities).

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 792 mg/kg bw

Based on:

test mat.

Mortality:

There were no mortalities

Clinical signs:

other: There were no significant signs of toxicity. Black or brown staining was seen on the application sites of all but one rat, which persisted for up to 4 days in male rats and up to 15 days in females.

Gross pathology:

No macroscopic findings were observed at necropsy.

Other findings:

SKIN IRRITATION
Signs of moderate skin irritation (including erythema, desquamation and scabbing) were observed in all animals, persisting for the majority of the study.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute dermal LD50 of test substance to males and females was greater than 2000 mg/kg bw, equivalent to 792 mg/kg bw test substance salt.

Executive summary:

In an acute dermal toxicity study, comparable to OECD TG 402 and in compliance with GLP, 5 male and 5 female young adult, Alpk:APfSD rats were each given a single 24 hour dermal application of 2000 mg/kg bw of test material (equivalent to 21.2 % w/w of test substance cation). The test material was applied without further dilution to the shorn backs of the rats and held in place under an occlusive dressing. At the end of the 24 hour application period, the dressings were removed and any residual test substance was removed from the skin using cotton wool swabs and clean warm water and the skin dried with tissue paper. The animals were observed daily, for 15 days, for any signs of toxicity or dermal irritation and their body weights were recorded at intervals. At the end of the study, the animals were killed and given a gross examination post mortem. There were no mortalities and no significant signs of toxicity were seen. Signs of moderate skin irritation were seen. The body weight of the animals was within the range commonly recorded for this age and strain. No macroscopic abnormalities were detected at necropsy. The acute dermal LD50 of test substance to males and females was greater than 2000 mg/kg bw, equivalent to greater than 792 mg/kg bw test substance (salt form).