thiamethoxam (ISO); 3-(2-chloro-thiazol-5-ylmethyl)-5-methyl[1,3,5]oxadiazinan-4-ylidene-N-nitroamine

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not specified

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

1987

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3-(2-chloro-thiazol-5-ylmethyl)-5-methyl-[1,3,5]oxadiazinan-4-ylidene-N-nitroamine

Cas Number:

153719-23-4

Molecular formula:

C8H10ClN5O3S

IUPAC Name:

3-(2-chloro-thiazol-5-ylmethyl)-5-methyl-[1,3,5]oxadiazinan-4-ylidene-N-nitroamine

Test material form:

solid: particulate/powder

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Remarks:

SPF rats

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 7 weeks old
- Weight at study initiation: 212 to 230 g in males and 160 to 181 g in females
- Housing: Individually in stainless steel wire mesh cages
- Diet: A pellet diet ad libitum
- Water: Tab water ad libitum
- Acclimation period: Approximately 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 3
- Humidity (%): 50 ± 20
- Air changes: 11 to 13 minutes per hour
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: Start: 6 Oct. 1995 End: 23 May 1996

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

PRELIMINARY DERMAL TOXICITY STUDY
In a preliminary acute dermal toxicity study, a group of three male and three female 7 week old CD(SD) rats had the test article administered at a dose level of 2000 mg/kg bw. No deaths were observed in either sex and therefore a single dose of 2000 mg/kg bw of the test material was administered dermally to a group of 5 male and 5 female (both 7 weeks old) CD(SD) rats.

TEST SITE & TEST ARTICLE
On the day prior to application of the test article, the dorsal area (approximately 30cm2 5 x 6cm) of each animal was clipped with an electric clipper. Immediately before administration, requisite amount of the test article was weighed for each animal and impasted by addition of 0.5 mL of distilled water. The test article was applied evenly to a gauze sheet (approximately 20cm2 4 x 5cm), placed on the application site and then covered with a polyethylene-film plaster and fixed with surgical tape.

REMOVAL OF TEST SUBSTANCE
After 24 hours of application, the dressing was removed and the application site was wiped with a gauze sheet. The reaction sites were then assessed.

Duration of exposure:

24 h

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

yes

Remarks:

distilled water

Details on study design:

- Duration of observation period following administration: 14 days
- The animals were examined frequently for the first six hours after dosing and twice daily in the morning and afternoon thereafter for 14 days for mortality and clinical abnormalities during the study.
- Body weights were recorded throughout the study.
- At the end of the scheduled observation period, all animals were necropsied and examined macroscopically.

Statistics:

For body weights, group mean values with standard deviation were calculated.

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:

No deaths occured during the study.

Clinical signs:

other: No abnormalities were observed in any animal.

Gross pathology:

No abnormalities were observed in any of the organs of the animals. Neither was there any change at the application site.

Other findings:

IRRITATION
There were no signs of irritability at the application site (dorsal skin).

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute dermal LD50 of the test substance after a single dermal application to rats of both sexes, observed over a period of 14 days is greater than 2000 mg/kg body weight.

Executive summary:

In an acute dermal toxicity study, groups of 7 week old Crj:CD (SD) strain SPF rats (each group consisting of 5 animals of each sex) were dermally exposed to the test substance (purity 98.60%) for 24 hours via a gauze sheet of 20 cm2 to the rodent dorsal area at doses of 0 or 2000 mg/kg bw. Animals then were observed for 14 days. The animals were examined frequently for the first six hours after dosing and twice daily in the morning and afternoon thereafter for 14 days for mortality and clinical abnormalities during the study. Body weights were recorded throughout the study. No death was observed in any animal at 2000 mg/kg bw. There were no treatment related clinical signs, necropsy findings or changes in body weight. The acute dermal LD50 of the test substance after a single dermal application to rats of both sexes, observed over a period of 14 days is in excess of 2000 mg/kg bw. In the clinical signs, no abnormalities were observed in any animal, nor was there any sign of irritability at the application site.