Is there a need for more precise definitions of bioavailability? Conclusions of a consensus workshop, Munich, September 9, 1989; under the patronage of the F.I.P.

After evaluation of the present definitions in a set of particular cases, it was agreed that there was no need for "more precise" definitions and that the current ones were adequate in the majority of cases. However, it was felt that the present definitions might be improved, in particular in view of the existence of non-systemically acting drugs and future "targeted drugs". Thus, the FDA definition might be modified as follows: "Bioavailability means the rate and extent to which the active drug ingredient or therapeutic moiety from a drug product becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action".