Reaction products of N,N'-ethane-1,2-diylbis(1,3-propanediamine), cyclohexane, peroxidized 4-butylamino-2,2,6,6-tetramethylpiperidine and 2,4,6-trichloro-1,3,5-triazine

Endpoint summary

Additional information

Toxicokinetic assessment

There were no studies available in which the toxicokinetic properties of the test substance were investigated. The test substance (molecular weight > 1300 g/mol) is a pale yellow powder (Ciba, 1997) with a Log Pow of > 10 (calculated, Novartis, 1997), a water solubility of < 40 µg/L at 20°C (Ciba, 1997), and a vapor pressure of < 0.001 Pa at 20°C (Ciba, 1997).

 

Absorption

Based on the physico-chemical data (low water solubility, molecule size, Log Pow) it is assumed that there is no or only very slow absorption after oral ingestion of the test article. This is supported by the available acute oral toxicity study (MB Research Labs, 1997) which did not reveal any signs of systemic toxicity and resulted in a LD50 of greater than 5000 mg/kg. Furthermore, in the available 28-day gavage toxicity study (Covance, 1997) which was performed with rats at dose levels of 10, 100 or 1000 mg/kg bw/day, no effects on body weight, food consumption, ophthalmology, clinical pathology, organ weights, and on histopathology were reported with a NOAEL of greater than 1000 mg/kg. The lack of systemic toxicity in these studies suggests poor bioavailability upon oral ingestion. As a result an accumulation of the test article in the body can be excluded. This is also supported by an ecotoxicity study in carp indicated that the test substance has no bioaccumulating potential.

Dermal absorption is equally unlikely, due to the size of the chemical, the Log Pow of > 10 and the very low water solubility. Highly lipophilic substances that come into contact with the skin can readily penetrate the lipid rich stratum corneum but are not well absorbed systemically. Although they may persist in the stratum corneum, they will eventually be cleared as the stratum corneum is sloughed off. Furthermore, dermal uptake of chemicals with a molecular weight >500 is not favored (ECHA GD 7c, 2008). This is in line with the available toxicity data after dermal exposure. In an acute dermal toxicity study (MB Research Labs, 1997) and in a guinea pig maximization assay (Hilltop, 1997), no indications of systemic availability after dermal application were detected. In conclusion, a dermal uptake of the test substance is expected to be low.

 

No reliable inhalation studies are available. However, given its very low vapor pressure and low water solubility, systemic availability after exposure to vapors or dust particle of the test substance is expected to be low. In addition, particle size distribution analysis revealed that 85.4% of the test substance consists of particles larger than 45 µm. Therefore, the majority of generated particles will not penetrate into the broncho-alveolar tract.

 

Excretion

In view of the absence of relevant findings and the expected low bioavailability, it can be assumed that the test substance is rapidly excreted. Since the test substance has a molecular weight larger than 500 g/mol and a low solubility in water, it is expected to be excreted predominantly via the feces (ECHA GD 7c, 2008).

 

Overall conclusion

The physico-chemical data suggest low oral and dermal absorption of the test substance which is supported by the findings of available toxicity studies. Therefore, bioavailability of the test substance is predicted to be low and rapid excretion via the feces is expected.