Foreword

Strategies for capillary electrophoresis: method development and validation for pharmaceutical and biological applications

This review is in support of the development of selective, reproducible and validated capillary electrophoretis (CE) methods. Focusing on pharmaceutical and biological applications, the successful use of CE is demonstrated by more than 800 references, mainly from 1994 until 1998. Approximately 80 recent reviews have been catalogued. These articles sum up the existing strategies for method development in CE, especially in the search for generally accepted concepts, but also looking for new, promising reagents and ideas. General strategies for method development were derived not only with regard to selectivity and efficiency, but also with regard to precision, short analysis time, limit of detection, sample pretreatment requirements and validation. Standard buffer recipes, surfactants used in micellar electrokinetic capillary chromatography (MEKC), chiral selectors, useful buffer additives, polymeric separation media, electroosmotic flow (EOF) modifiers, dynamic and permanent coatings, actions to deal with complex matrices and aspects of validation are collected in 20 tables. Detailed schemes for the development of MEKC methods and chiral separations, for optimizing separation efficiency, means of troubleshooting, and other important information for key decisions during method development are given in 19 diagrams. Method development for peptide and protein separations, possibilities to influence the EOF and how to stabilize it, as well as indirect detection are considered in special sections.

Therapeutic drug monitoring by capillary electrophoresis

Because of the ease of analysis and the high resolution, drug analysis is becoming the best example for the application of capillary electrophoresis. Therapeutic drug monitoring is a specialized area of drug analysis performed in clinical laboratories for patient care. CE offers high resolution and speed with the low operating costs needed in patient care. However, CE has a few limitations, mainly poor detection limits and precision. Simple methods of stacking, which enhance drug detection to overcome the poor sensitivity of CE are stressed. Serum has a unique matrix with a high content of proteins and salts which can have adverse effects on separation by CE. For successful analysis, special maneuvers are employed to decrease these matrix effects. Studies that have addressed the improvement of the precision of CE are summarized. CE offers the possibility of bringing chiral separations into the routine arena.