The impact of capillary electrophoresis in drug analysis and bioanalysis

Capillary electrophoresis (CE) has penetrated a wide variety of areas of separation science during the last ten years. The relative strengths and weaknesses of this technique are here overviewed, by citing the most recent literature and updated Medline search, keeping an eye on technology news, as technology and the development of CE and its applicability progress in parallel. The issues discussed include micellar electrokinetic chromatography (MEKC), which permits non-ionic solutes to be solubilized and separated. Enantioselective applications in CE exploit addition to the run buffer of cyclodextrins, macrocyclic antibiotics and proteins for analysis of chiral drugs and the state of the art of this field will be emphasized. CE has significant potential for drug metabolism studies, especially coupled with MS for high sensitivity detection and structural characterisation. Strategies for the analysis of drugs and metabolites in body fluids include on-capillary methods of sample concentration and single-step analyses with direct injection of body fluids on-column, where detection techniques other than conventional UV are essential to achieve adequate sensitivity. The potential contribution of the hybrid technique of capillary electrochromatography (CEC), which couples the separating power of reversed-phase HPLC and the high efficiency of CE, has recently attracted growing interest and is therefore discussed. Finally, validation issues which are peculiar to CE are illustrated.