High pressure liquid chromatographic analysis of the serum concentration of cefuroxime after an intravenous bolus injection of cefuroxime in patients with a coronary artery bypass grafting.

A simple reversed-phase high pressure liquid chromatographic method was developed for the determination of cefuroxime in the serum of patients undergoing coronary artery bypass grafting. The serum was cleaned up with a 3.3% solution of perchloric acid in water. Cefalexine was used as an internal standard. Detection was made by a UV multi-wavelength detector. The optimum wavelength for cefuroxime is 275 nm. The absolute recovery of this method was 90.9%; the limit of quantification was 0.7 mg/l. This analytical method was used in a study to investigate the cefuroxime serum concentration--time curves in 26 patients undergoing coronary artery bypass grafting. It was found that one single dose is sufficient to obtain effective serum concentrations.

High-performance liquid chromatographic assay of flecainide and its enantiomers in serum.

Two analytical methods are described for the determination of flecainide in serum by high-performance liquid chromatography employing spectrofluorimetric detection. One method concerns total flecainide, whereas the other covers the assay of flecainide enantiomers separately. The stereo-specific assay is based on a precolumn derivatization of flecainide enantiomers to urea derivatives with the chiral compound R-(+)-1 phenyl-ethyl-isocyanate. By formation of the permanent diastereomers, the racemic mixture can be resolved with a traditional reversed-phase column. The run time of the total flecainide assay is 15 min, whereas that of its enantiomers is 20 min. The extraction recovery from serum in both methods is 85%. The intraassay precision of the nonstereospecific assay in serum ranged from 99 +/- 3% (coefficient of variation) to 101 +/- 5%. The accuracy of the estimation in serum ranged from 100 to 103%. The intraassay precision of the stereospecific assay in serum ranged from 98 +/- 5% (coefficient of variation) to 103 +/- 7%. The accuracy of the estimation in serum ranged from 101 to 104%. The limit of quantitation was 0.05 mg/L for both methods.