Phenol, 2,4-bis[(dodecylthio)methyl]-6-methyl-

Endpoint summary

Description of key information

Since there is no data on acute toxicity for the substance (EC 438-600-3) available, a read-across to the structural analogon 4,6-bis(octylthiomethyl)-o-cresol has been conducted. It does not show acute oral and dermal toxicity with a LD 50s greater than 5000 mg/kg bw  for the oral route of exposure and greater than 2000 mg/kg bw for the dermal route of exposure as shown in valid guideline studies performed pursuant to OECD Guidelines 401 (Acute Oral Toxicity) and 402 (Acute Dermal Toxicity), respectively. Experimental data on acute inhalation toxicity is waived.

Additional information

No data on acute toxicity for the substance (EC 438-600-3) available. Read-across to 4,6-bis(octylthiomethyl)-o-cresol is applied.

The read-across substance differs in the length of the alkyl chain at the thio ether. Specifically, it is a C8 chain in comparison to a C12 chain in the target substance. Due to the shorter chain length, the molecule is smaller and predicted to be of slightly better solubility in water. Therefore, it is considered to be of better systemic availability which might result in a slightly higher toxicity compared to the target substance. As both C8 and C12 chains are metabolized via beta oxidation, both substances are predicted to have the same metabolites. Overall read-across is justified and it was accepted by the Competent Authority for ELINCS registration.

Oral Route of Exposure

In a limit test performed according to OECD Guideline 401 (Acute Oral Toxicity), groups of Tif: RAIf (SPF) rats (5 rats/sex/dose) were given a single oral dose (gavage) of the test substance at a single dose of 5000 mg/kg bw. The animals were observed subsequently for a period of 14 days. No mortality occurred during the14 day observation period. Dyspnoea, exophthalmoses, ruffled fur, and curved body position were seen, beginning as early as 1 hour post dosing and lasting up to 10 days. The animals fully recovered within 11 days. At necropsy, no gross lesions were observed. As no deaths occurred in the study, the LD 50 of the test article in rats is higher than 5000 mg/kg bw (Ciba Geigy Ltd., 861243).

Dermal Route of Exposure

In a limit test performed according to the OECD Test Guideline 402, a pilot sample was applied semi-occlusively for 24 hours to the shaved skin of 5 (7 - 8 weeks old) Tif: RAIf(SPF) albino rats /sex at a dose level of 2000 mg/kg bw. Animals were then observed for 14 days. No mortality was registered in the observation period. No local skin effects were observed at the application site. Treatment-related symptoms were dyspnoea, exophthalmoses, ruffled fur, and abnormal body position, which are common symptoms in acute tests. Additionally, sedation was found from three hours after the application up to day 1. All observed symptoms were reversible within 10 days after dosing. Necropsy revealed no gross abnormalities. As no deaths occurred in the study, the LD 50 of the test article in rats is higher than 2000 mg/kg bw (Ciba Geigy Ltd., 861246).

Inhalation Route of Exposure

No acute inhalation study is needed as acute oral and dermal studies are available (according to Annex VIII of REGULATION (EC) No 1907/2006).

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, as amended for the 28th time in Directive 2001/59/EC.

 

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

The available experimental test data are 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 as amended for the second time in Directive EC 286/2011..