Butanamide, 2-[2-(2-methoxy-5-nitrophenyl)diazenyl]-N-(2-methoxyphenyl)-3-oxo-

Endpoint summary

Description of key information

In an acute oral toxicity study conducted according to the OECD-Guideline 423 in rats (BASF SE, 2008), the oral LD50 was determined to be > 2000 mg/kg bw. No mortality was observed.

In an acute inhalation toxicity study according to the OECD-Guideline 403 in rats (BASF SE, 2013), the inhalative LD50 was determined to be > 2100 mg/m³ air. No mortality was observed.

In an acute dermal toxicity study according to the OECD-Guideline 402 in rats (BASF SE, 2009), the dermal LD50 was determined to be > 2000 mg/kg bw. No mortality was observed.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

GLP and guideline compliant study report.

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating conc.

Value:

2 100 mg/m³ air

Quality of whole database:

GLP and guideline compliant study report.

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

GLP and guideline compliant study report.

Additional information

Acute oral toxicity

In the available BASF SE (2008) study the acute toxic effects of the test substance were investigated after a single peroral administration to rats. The investigations were performed in accordance with the OECD-Guideline 423. The test substance (purity > 95 %) was (suspended in deionised water) administered once orally via gavage to female Crl:(WI)BR rats (dose volume was 20 mL/kg bw). Dosing was performed sequentially to groups of 3 animals starting at 2000 mg/kg bw. Body weight and body weight gains were determined before administration, 7 and 14 days after the administration (p.a.). Clinical observations were performed at least once per day during the 14 days observation period and all animals were sacrificed and necropsied at the end of the observation period.

No toxic effects of the test substance were noted in life and post mortem at a dose of 2000 mg/kg bw. No mortality occurred. As no animals died, the oral LD50, was determined to be > 2000 mg/kg body weight. Based on the guidance given in OECD guideline 423 (Annex 2d), the oral LD50, can be assessed to be > 5000 mg/kg body weight.

  

Acute inhalation toxicity

A study for acute inhalation toxicity following GLP and OECD testing guideline 403 was performed with the test substance (BASF SE, 2013). A group of five male and five female albino rats [RccHanTM:WIST(SPF)] was exposed by nose-only, flow-past inhalation for four hours to the test item at a gravimetrically determined mean concentration of 2.1 mg/L air. All animals were observed for clinical signs and mortality during the inhalation exposure and the subsequent 14-day observation period. Body weights were recorded prior to exposure on test day 1, and during the observation period on test days 2, 4, 8 and 15 before necropsy. On test day 15 all animals were sacrificed and necropsied. The aerosol concentration, temperature, relative humidity, oxygen content and airflow rate measured during the exposure were considered to be satisfactory for a study of this type. In addition, the test item was considered to be respirable for rats.

All animals survived the scheduled observation period. Clinical signs were limited to the day of treatment and consisted of slightly ruffled fur in all animals and slight tachypnea in 3 males and 2 females. From test day 2 onwards, all animals were free from clinical signs. Slight body weight loss was noted between test days 1 and 2 in all males and 4 females. In 3 of those females, this finding persisted up to test day 4. Thereafter normal body weight development was recorded. There were no macroscopical findings at necropsy. The LC50 for 4-hour exposure of the substance was > 2.1 mg/L air (gravimetrically determined mean aerosol concentration). This concentration was the highest attainable one for respirable dust.

Acute dermal toxicity

In the available BASF SE (2009) acute dermal toxicity study conducted according to the OECD Guideline 402 (Limit Test), young adult Wistar rats (5 ♂ and 5 ♀) were dermally exposed to a single dose of 2000 mg/kg bw of test substance (as suspension in olive oil Ph.Eur.) to the clipped skin (dorsal and dorso-lateral parts of the trunk, covered by semi occlusive dressing) for 24 hours. The application area corresponded to at least 10 % of body surface area. The animals were observed for 14 days.

No signs of systemic toxicity were observed in the animals. Due to a yellowish discoloration (up to day 9 after treatment) of the application area caused by the test article erythema could not be evaluated in all male animals. Mean body weight of the female animals decreased or remained stable during the first post-exposure observation week, probably due to the bandage procedure, but increased during the second week within the normal range. The mean body weight of the male animals increased throughout the study period within the normal range. No macroscopic pathologic abnormalities were noted in the animals examined at the end of the study.

Since no mortality occurred, the acute dermal median lethal dose (LD50) was determined to be > 2000 mg/kg bw in rats.

Justification for classification or non-classification

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008.

As a result the substance is not considered to be classified for acute oral, inhalatory and dermal toxicity under Regulation (EC) No 1272/2008, as amended for the tenth time in Regulation (EU) No 2017/776.