[Name confidential or not available]

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics, other

Type of information:

other: expert statement

Adequacy of study:

supporting study

Applicant's summary and conclusion

Executive summary:

No specific study was performed on the absorption, distribution, metabolism and/or excretion (ADME) of WS400506. Predictions on toxico-kinetics were based on physical-chemical properties and results of toxicological studies.

The UVCB substance consists of esters of various fatty acids (primarily C18 from tall oil) and 4,4'-Isopropylidenediphenol, oligomeric reaction products with 1-chloro-2,3-epoxypropane. The molecular weight of the esters amounts to approx. 900 Da. Water solubility is very low, < 1 mg/l. The water/octanol partition coefficient was determined to amount to amount to log Pow > 6. Determination of the vapour pressure resulted in a value of 0.0004 Pa.

The physico-chemical and toxicological information on the substance has been used to assess its toxicokinetic behaviour according to the ECHA “Guidance on information requirements and chemical safety assessment Chapter R.7c: Endpoint specific guidance”.

Dermal absorption

The low water solubility and high lipophilicity (log Pow > 6) together with the high molecular weight of the constituents of WS400506 will limit absorption across the skin. No dermal or eye irritation was observed.

 

Oral absorption

The low water solubility and high lipophilicity (log Pow > 6) together with the high molecular weight of the constituents of WS400506 will limit absorption in the digestive tract. However, after repeated dosing of rats with high levels of WS400506 (>= 300 mg/kg/day) intestinal changes were observed in mesenteric lymph nodes and in the small intestines (not being associated with any inflammatory or degenerative changes). This indicates that some absorption via oral exposure is possible.

 

Respiratory absorption

WS400506 is a waxy solid and has a very low vapour pressure. It decomposes before boiling. Accordingly, inhalation is an unlikely route of human exposure.

 

Distribution, metabolism, and excretion

There is no information available on distribution, metabolism, and excretion of WS400506 in the available studies.

 

Based on the available data the bioacumulation potential cannot be judged. However, based on the favourable testing results, i.e. low toxicological potential, on the one hand and on the very low dermal and inhalative bioavailability of the substance (due to its physical-chemical properties) on the other hand there is no need for further investigations of a bioaccumulation potential.