2-(2H-benzotriazol-2-yl)-4,6-ditertpentylphenol

Endpoint summary

Description of key information

In the CIBA-Geigy (Siss 6481, 1978) acute oral toxicity study, conducted similar to the OECD-Guideline 401, the oral LD50 was determined to be > 7750 mg/kg body weight (no mortality). In the CIBA-Geigy (Siss 3502, 1973) acute inhalation toxicity study, conducted similar to the OECD-Guideline 403, the inhalative LC50 was determined to be > 0.4 mg/l (no mortality). In the Geigy (U. K.) Ltd. (8/69/S. L., 1969) acute dermal toxicity study, conducted similar to the OECD-Guideline 402, the dermal LD50 was determined to be > 1100 mg/kg body weight (no mortality).

Additional information

Acute oral toxicity

In the CIBA-Geigy study (Siss 6481, 1978) the acute oral toxicity of the test substance was determined after a single oral administration to rats. The study was conducted similar to the OECD-Guideline 401. The test substance was suspended in polyethylene glycol and administered once orally via gavage to Tif: RAIf (SPF) rats of both sexes (body weight 160 – 180 g, 5 animals each dose group and sex) at doses of 4640, 6000, and 7750 mg/kg body weight, respectively. Prior treatment the animals adapted to the lab for a minimum of 4 days and fasted over night. The physical conditions and deaths were monitored throughout the whole observation period of 14 days. Within two hour of treatment sedation, dyspnoe, curved position and ruffled fur were reported for all dosage groups. The animals recovered within 8-9 days and the autopsy did not reveal any substance related gross organ changes. No mortality occurred. The oral LD50 was determined to be > 7750 mg/kg body weight.

The results of the acute oral toxicity are supported by the findings of the studies performed by CIBA-Geigy (No. 874133, 1987) and the University of Miami (No. 62, 1977), both conducted similar to the OECD guideline 401 after single administration of the test substance to rats.

Acute inhalation toxicity

In the available CIBA-Geigy study (Siss 3502, 1973) the acute inhalation toxicity of the test substance was determined after a single exposure to rat. The study was conducted similar to the OECD-Guideline 403. The test substance was suspended in ethanol and injected as aerosol into the exposure chamber. The output of the spray device and the dimensions of the inhalation chamber are so adjusted to each other that the solvent evaporates on the way from the nozzle orifice to the rat containers. The animals (9 Tif. RAIf rats of each sex) were exposed via a nose-only system to a technically maximal achievable analytical substance concentration of 0.4 mg/l for 4 hours and the particle size distribution was approximately 7.5 % > 7 µm, 5 % 3-7 µm, 55 % 1-3 µm, and 32.5 % < 1 µm. Control animals were included into the study, which were exposed to the vehicle. The body weight gains were within the normal range in males and females during the whole study period and no clinical symptoms were observed during the 4-hour exposure and the subsequent 7-day observation period. The autopsy did not reveal any compound related gross organ changes. No mortality occurred. The inhalative LC50 was determined to be > 0.4 mg/l.

Acute dermal toxicity

In the Geigy (U. K.) Ltd. study (8/69/S. L., 1969) the acute dermal toxicity of the test substance was determined after a single exposure to rabbit. The study was conducted similar to the OECD-Guideline 402. 3 g of the test substance was suspended in polyethylene glycol and applicated with an approx. concentration of 1100 mg/kg body weight to young adult albino rabbits (two animals each sex). The rabbits were shaved 24 hours prior treatment, whereas one of each sex was further prepared by making epidermal abrasions every 2 – 3 cm longitudinally over the area of exposure. The shaved area constituted about 10 % of the total body surface area. After application of the test substance the test site was covered by wrapping the trunk with an impervious plastic sheeting. The test compound remained in contact with the skin for 24 hours, until the animals were thoroughly cleaned and the exposure sites were examined for local reactions. The animals were observed for 14 days. Very slight and well definded erythema was observed at 24 hours, but was reversible within 72 hours. The autopsy did not reveal any gross pathology changes. No mortality occurred. The dermal LD50 was determined to be > 1100 mg/kg body weight.

In summary, the results from the acute toxicity studies do not indicate test substance related acute toxic effects, even if the test substance is assumed to be systemic available (for reference see acute oral and inhalative studies). No test material induced clinical signs of toxicity occured when the animals were treated through the inhalative route or after single oral administration of the test substance. Furthermore, according to the physico chemical parameters, the test substance is unlikely to be taken up by the dermal route (for reference see toxicokinetics assessment). Hence, in the acute dermal toxicity study no signs of toxic effects caused by the test substance were reported. Concluding, the LD50 dermal is estimated to be > 2000 mg/kg bw.

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available experimental test data is reliable and suitable for the purpose of classification under Directive 67/548/EEC. Based on the data, classification for acute toxicity is not warranted under Directive 67/548/EEC.

 

Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data is reliable and suitable for the purpose of classification under Regulation (EC) No.1272/2008. Based on the data, classification for acute toxicity is not warranted under Regulation (EC) No.1272/2008.