Pharmaceuticals are becoming increasingly prevalent in the
environment. To enable policy makers, regulators and industry
to prioritise compound, or classes of compounds, that may
require a management strategy it is necessary to identify those
pharmaceuticals that pose a potential environmental risk. A
component of risk evaluation requires studies using fish with
bioaccumulation forming part of this assessment. There is
move to find alternatives to whole animal testing as part of the
3Rs (refinement, reduction and replacement) agenda. Current
in silico models of organic compound uptake in fish are based
primarily on lipophilic, neutral compounds; these models may
not be applicable to polar or ionisable compounds. It is estimated
that 70% of pharmaceuticals are ionisable compounds and the form
they take is dependent on their acid dissociation constant (pKa)
and pH of the surrounding water. Empirical data is necessary to
develop models of uptake of ionisable compounds. A primary fish
gill cell culture system has shown significant promise as an in vitro
replacement model system for whole fish compound uptake studies
as well as environmental monitoring. The current presentation will
present some of this data with a specific focus on the relationship
between the uptake of the pharmaceutical and various chemical
parameters such as Log Kow , Log S, Log D, and pKa.