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Description of key information

The oral LD50 is >2500 mg/kg bw. The inhalation LC50 is >139.7 mg/l (analytical concentration) / >153.7 mg/l (nominal concentration). The dermal LD50 is >2000 mg/kg bw.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
2 500 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Dose descriptor:
LC50
139 700 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
2 000 mg/kg bw

Additional information

Acute oral toxicity

In a GLP compliant study according to OECD guideline 423 and EU method B.1tris the acute oral toxicity of AC-6000 following a single oral administration in the Sprague-Dawley CD strain rat was investigated (SafePharm Laboratories, 2006).

A group of three fasted females was treated with AC-6000 at a dose level of 2000 mg/kg bw by gavage. This was followed by a further group of three fasted females at the same dose level. The test material was administered orally undiluted. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

There were no deaths or signs of systemic toxicity. All animals showed expected gains in bodyweight over the study period. No abnormalities were noted at necropsy.

The acute oral median lethal dose (LD50) of the test material in the female Sprague-Dawley CD strain rat was estimated to be greater than 2500 mg/kg bw.

Acute inhalation toxicity

In a GLP compliant study according to OECD guideline 403 and EU method B.2 the acute inhalation toxicity of AC-6000 following a single four-hour inhalation period in the Wistar strain rat was investigated (Syngenta Central Toxicology Laboratory, 2007). Two groups, each containing five male and five female animals, were exposed nose-only to AC-6000 at a target concentration of either 1400 ppm (analytical concentration of 1443 ppm / 20.9 mg/l) or 10000 ppm (analytical concentration of 9631 ppm / 139.7 mg/l). Following exposure, the animals were retained without treatment for 14 days. Clinical observations and bodyweights were recorded throughout the study and at the end of the scheduled period, the animals were killed and subjected to a gross examination.

No animals died during the study. Clinical findings were mainly confined to observations associated with restraint (wet fur) with only transient irregular breathing noted in animals during exposure to the highest concentration. All animals gained weight during the study. At necropsy, no treatment related macroscopic findings were noted.

Nose-only exposure for 4 hours to target concentrations of 1400 ppm (analytical concentration of 1443 ppm / 20.9 mg/l) or 10000 ppm (analytical concentration of 9631 ppm / 139.7 mg/l) resulted in no deaths and no adverse effects. It is concluded that the median lethal concentration of AC-6000 exceeds 10000 ppm (analytical concentration of 9631 ppm / 139.7 mg/l).

Acute dermal toxicity

In a GLP compliant study according to OECD guideline 402 and EU method B.3 the acute dermal toxicity of AC-6000 following a single dermal application for 24 hours in the Wistar strain rat was investigated (NOTOX B.V., 2008). A group of five male and five female animals were exposed to AC-6000 at a dose level of 2000 mg/kg bw. Animals were subjected to daily observations and weekly determination of body weight. Macropscopic examination was performed on the day of death or after terminal sacrifice (day 15).

On male was found dead on day 2. No further mortality occurred. The males showed hunched posture, ptosis, chromodacryorrhoea and/or flat posture on days 1 and 2. Two females showed chromodacryorrhoea on days 1 and/or 2. Scabs were seen in the treated skin-area of one male during the study period. The changes noted in body weight gain in males and females were within the range expected for rats used in this type of study. No abnormalities were found at macroscopic post mortem examination of the animals.

The dermal LD50 value of AC-6000 in Wistar rats was established to exceed 2000 mg/kg bw.

Justification for classification or non-classification

Based on the results of the acute oral, inhalation and dermal toxicity studies, classification according to EU Directive 67/584/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 is not needed.