Benzenesulfonamide, N-(4-hydroxyphenyl)-

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Type of information:

other: Assessment based on available information

Adequacy of study:

key study

Justification for type of information:

Oral adsorption can be present as:
• Molecular weight (MW) of the substance is moderate (249 g/mol) which is favourable for adsorption. Generally, the smaller the molecule the more easily it may be taken up. Molecular weights below 200 g/mol are very favourable for absorption (pass through aqueous pores or be carried through epithelial barrier by the bulk passage of water) which is not the case for this substance.
• The substance is very hydrophilic (water solubility: 0.8 g/l). Water-soluble substances will readily dissolve into the gastrointestinal fluids.
• Log Pow is fairly low (2) which is favourable for absorption by passive diffusion. Adsorption of hydrophilic substances is possible by the ability of such substances to dissolve into gastrointestinal fluids and hence make contact with the mucosal surface.
• No signs of systemic toxicity were present in the oral toxicity studies. Respiratory adsorption will be limited as:
• The substance has a very low vapour pressure (1.1 x 10-7 Pa) and is therefore not available for inhalation as a vapour. • Only 12.5 mg dust/ g substance (1.25%) can become airborne. Moreover only 25% of the particles is <15 μm, which have the potential to be inhaled and reach the alveolar region.
• The substance has a low log Pow, and if the substance would enter the respiratory tract, could therefore be adsorbed directly across the respiratory tract epithelium by passive diffusion.
• The substance has a logP > 0. Crossing alveolar and capillary membranes is favourable.
• No signs of systemic toxicity data are present in the inhalation toxicity data. Dermal adsorption will be limited as:
• Liquids are taken up more easily than dry particulates. Dry particulates will have to dissolve into the surface moisture of the skin before uptake can begin.
• Substances with MW > 100 g/mol can not be easily taken up dermally. Log Pow < 4 means that uptake into the stratum corneum will be low since stratum corneum has a great barrier function against hydrophilic compounds.
• The substance has a high water solubility, it can partition from the stratum corneum into the epidermis. However it is not likely to be taken up by the stratum corneum.
• Skin irritation/corrosion test did not cause damage to the skin.
• The substance is a skin sensitizer. Adsorption through inhalation or dermal uptake is not likely. Oral uptake is however likely. However based on the repeated dose/reproductive screening test, no effects were seen.