Registration Dossier

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
basic toxicokinetics in vitro / ex vivo
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:

Description of key information

No toxicokinetic data is available on p-TSH (T) and the primary read-across substance OBSH (S1). As no specific data for the absorption rate from the oral, the dermal or the inhalational route of exposure is available, default assumption will be applied. Thus, absorption from dermal and inhalational route is considered to be the same as for the oral route

Key value for chemical safety assessment

Absorption rate - oral (%):
100
Absorption rate - dermal (%):
100
Absorption rate - inhalation (%):
100

Additional information

In hydrolysis testing the hydrolysis of p-TSH into toluene-4-sulphonic acid has been confirmed with T1/2 = 38.5 h (20 °C, pH 7) and T1/2 = 139 h (20 °C, pH 4). The other metabolite is most likely hydrazine (not specifically identified in the test) that may be of concern due to its high toxicity. The hydrolysis half-life for the source substance OBSH is considerable lower and thus the potential toxicity of liberated hydrazine is expected to more expressed for OBSH than for p-TSH. Also, the non-hydrolysed OBSH (containing two arylsulphonylhydrazide units) is considered as a relevant read-across substance for the non-hydrolysed p-TSH (a single arylsulphonylhydrazide), due to the close structural similarity of the substances.