Chapter Analysis of Chiral Drugs in Body Fluids
Understanding the contribution of stereochemistry to the action and disposition of drugs is essential to the successful development of chiral drugs as well as to establishing if a drug already developed or used as a racemic mixture might be replaced by a safer or more effective pure single isomer. Thus, the demand for analytical methods suitable for the accurate and precise determination of enantiomers of drugs and their metabolites in biological samples has increased signi cantly over the last
years . High-performance liquid chromatography (HPLC) has been frequently used in pharmacokinetic and metabolism studies as well as for other applications. In contrast to HPLC, there are relatively few reports regarding the application of electromigration techniques (capillary electrophoresis, CE and capillary electrochromatography, CEC) in the chiral separations of drugs in biological samples. However, the number of studies in this area has increased in the last years . The increase in the interest in CE and CEC techniques is mainly supported by their high-ef ciency separation power which allows baseline resolution of enantiomers even at low degree of enantioselectivity and prevents the interference of matrix compounds, metabolites and other coadministered drugs. Other features such as suitability for the analysis of polar and/or basic drugs and their metabolites, speed and reduced operational costs, simplicity of instrumentation, relatively easy method of development, and requirement of small amounts of samples make electromigration methods particularly attractive for this application .