ONLINE COLUMN-SWITCHING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ANALYSIS OF CARDIOVASCULAR DRUGS IN SERUM WITH AUTOMATED SAMPLE CLEANUP AND ZONE-CUTTING TECHNIQUE TO PERFORM CHIRAL SEPARATION

A selective and highly reproducible, multi-column HPLC method is descr ibed for the analysis of the following cardiovascular drugs: lidocaine , pindolol, metoprolol, oxprenolol, diltiazem and verapamil, in serum. Column-switching devices are employed in combination with advanced se paration media technologies for the automated analysis of samples cont aining complex matrices. The method consists of on-line sample clean-u p using a restricted access sorbent, HPLC analysis of the drugs on a m icrosphere non-porous silica RP-18 column, and front-cutting to perfor m the chiral separation of pindolol enantiomers on a second HPLC syste m. Simultaneous control of the two HPLC systems and data analysis is a chieved from a single centralized software. The R.S.D. values of the p eak areas for spiked serum are less than 1% for metoprolol and oxpreno lol, 2-5% for lidocaine, diltiazem and verapamil, and 1.2 and 2.4% for the two pindolol enantiomers. Recoveries, limits of detection and lin earities are provided.