The use of microdialysis in CNS drug delivery studies - Pharmacokinetic perspectives and results with analgesics and antiepileptics

Microdialysis can give simultaneous information on unbound drug concentrati on-time profiles in brain extracellular fluid (ECF) and blood, separating t he information on blood-brain barrier (BBB) processes from confounding fact ors such as binding to brain tissue or proteins in blood. This makes microd ialysis suitable for studies on CNS drug delivery. It is possible to quanti fy influx and efflux processes at the BBB in vivo, and to relate brain ECF concentrations to central drug action. The half-life in brain ECF vs, the h alf-life in blood gives information on rate-limiting steps in drug delivery and elimination from the CNS. Examples are given on microdialysis studies of analgesic and antiepileptic drugs. (C) 2000 Elsevier Science B.V. All ri ghts reserved.