Tetramethylene dimethacrylate

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

A subchronic toxicity study inhalation does not need to be conducted. The Finnish Competent authority concluded in the recently submitted CLH dossier based on toxikokinetic data as followed regarding the absorption after inhalation:"The vapour pressure of the substance is 0.1 Pa at 20°C. This falls well below the general cut-off value of 0.5 kPa, indicating very low volatility and hence poor availability for inhalation as a vapour (ECHA 2017a). Solid particles, however, may be available for absorption after inhalation of an aerosolized substance, although this does not seem likely considering the size of the molecule. There are no studies regarding absorption of tetramethylene dimethacrylate from the respiratory tract."
Furthermore, it is well known and widely accepted that the methacrylate esters are metabolised by endogenous carboxylesterases. Furthermore, it is well known that the methacrylate esters are metabolised by endogenous carboxylesterases to methacrylic acid and the corresponding alcohol. The critical substance, Methyl methacrylate, is only used as read across donor substance for methacrylic acid due to the strong corrosive properties of the acid. Therefore, it is irrelevant for risk assessment on 1,4-BDDMA, if the metabolites are inhalable, since they were generated inside the human body.

For this issue, please also refer to the "CLH Dossier on 1,4-BDDMA" as attached in IUCLID Section 13.2..