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Description of key information

No experimental studies regarding toxicokinetics of DPX-C and Dibenzetano are available. Nevertheless available data and information derived from the testing strategy adopted for the chemical permit to evaluate main aspects of the substance toxicokinetics.

DPX-C is expected to be absorbed by oral route, because systemic effects were observed in the 28-day oral toxicity study. Considering the molecular structure of Dibenzetano, which differs only by the absence of chlorine atoms, also this molecule is expected to be absorbed by oral route.

No absorption is foreseen by inhalation route, according to the particle size of the two substances: DPX-C is not expected to enter the respiratory airways, while Dibenzetano does not penetrate at thoracic level (> 10 µm, therefore it is not expected to pass the larynx by inhalation exposure but it is expected to be removed by coughing followed by swallowing into the gastrointestinal tract). Moreover, the acute inhalation toxicity study was discharged because technically not feasible.

According to molecular weight and hydrophobicity of the two molecules, dermal absorption is foreseen, although no systemic effects were observed in the acute dermal toxicity study.

According to the logKOWof the two substances, bioaccumulation cannot be excluded, but according to the results of a Russian study, which reliability is however not assessable, the cumulative capacity is weak (Frolova et al., 1991).

Systemic effects observed in the 28-day oral repeated toxicity study may indicate hepatic metabolism and renal excretion. Indeed predicted metabolism data for DPX-C indicate a possible hydroxylation of the aromatic ring and subsequently a conjugation with glutathione or glucuronic acid. Predicted metabolism of Dibenzetano, in addition to conjugation with glutathione or glucuronic acid, may involve the conjugation with mercapturic acid, sulphonation and methylation. The metabolic aim of these conjugations is to improve renal excretion of the substances. The above assumption on metabolism and excretion of DPX-C and Dibenzetano may be supported by the article of Frolova et al. (1991).

Key value for chemical safety assessment

Bioaccumulation potential:
low bioaccumulation potential
Absorption rate - oral (%):
100
Absorption rate - dermal (%):
100
Absorption rate - inhalation (%):
100

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