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Description of key information

Key value for chemical safety assessment

Additional information

No specific studies are available on the absorption, distribution, metabolism, or excretion of the intermediate DCB 58%, but data on one of the main non-salified component 4,4'-sulfonyldiphenol (BPS), is available.

According to a 28-day repeated dose oral toxicity test on BPS in rats, 2 males died in the 1000 mg/kg bw/day group. In pathological examinations, changes were observed in the cecum, liver, thymus, adrenal, spleen, bone marrow and kidney.

Those findings suggest oral absorption and distribution to those organs in rats.

In general human populations, BPS (free plus conjugated) was found in 81% of 315 urine samples at concentrations ranging from below the LOQ (i. e.,0.02 ng/mL) to 21.0 ng/mL, with a mean value of 0.654 ng/mL (0.598μg/g Cre).1

The Dermal Permeability Coefficient Program (DERMWIN) v2.0 estimates the dermal permeability coefficient (Kp), the dermally absorbed dose per event (DAevent) and Dermal Absorbed Dose (DAD) of organic compounds via water contact.

The estimated Kp of BPS is 0.000767 cm/hr and the value suggests that the intermediate to be registered could be less absorbed by the skin.2

In a modelling study of 2010, dermal absorption was calculated to be 2.8% for sodium xylenesulphonate.3

Phenol, that is present in the whole mixture of the intermediate DCB in a low concentration (1.8%) is readily absorbed by the inhalation, oral, and dermal routes. Once absorbed, phenol is widely distributed in the body, although the levels in the lung, liver, and kidney are often reported as being higher than in other tissues (on a per-gram-tissue basis).

Elimination from the body is rapid, primarily as sulfate and glucuronide conjugates in the urine, regardless of the route of administration. Phenol does not appear to accumulate significantly in the body.4

The conclusion based on the available data is that DCB 58% could be orally absorbed, but much less absorbed through the skin.

References:

1SIDS INITIAL ASSESSMENT PROFILE, CoCAM 4, 16-18 April 2013;

2EPI Suite v. 4.11 (EPA’s office of Pollution Prevention Toxics and Syracuse Research Corporation SRC);

3ECHA Registration dossier, sodium xylenesulphonate CAS 1300 -72 -7;

4Toxicological review of phenol. EPA, IRIS, 2002, EPA/635/R-02/006.