During the last two decades, a number of methods have been developed for in
vivo collection, separation and characterization of biological samples and
analytes. The capability acid reliability of the microdialysis technique f
or measuring endogenous substances (such as neurotransmitters and their met
abolites) as well as exogenous therapeutic agents in various tissue systems
have brought it to the forefront of the in vivo tissue sampling methods. T
he usability of this technique is demonstrated by its application as report
ed in almost 3600 scientific papers (as of January 1998). This paper descri
bes the general aspects and various applications of this fast growing techn
ique. Emphasis has been given to analytical considerations with regards to
microdialysis probe recovery and newer HPLC techniques. Copyright (C) 1999
John Wiley & Sons, Ltd.