COLUMN-SWITCHING TECHNIQUES IN THE BIOMEDICAL ANALYSIS OF STEREOISOMERIC DRUGS - WHY, HOW AND WHEN

The application of stereoselective chromatographic techniques to bioan alytical problems has become a routine procedure. However, this approa ch is not always straightforward; particularly when the separation inv olves chromatographic chiral stationary phases. Matrix interferences a nd more importantly, overlapping metabolite peaks often make direct an alysis impractical. One strategy to overcome these problems is to comb ine two or more columns with different selectivities to produce a mult i-dimensional chromatographic system. This review addresses the use of coupled column chromatography in HPLC systems including different cou pling methods and the application of the resulting arrangements to bio analytical analyses.