Carvedilol demonstrates α1-, β1-, β2- receptor blocking activity and has recently been used for the treatment of heart failure. The serum concentrations of carvedilol were measured by high performance liquid chromatography (HPLC) using the method of Hokama et al. and Louis et al. with slight modifications. To extract carvedilol from the serum, we employed solid-phase extraction. The retention times of carvedilol and the internal standard were 7.1 and 5.8 minute, respectively. The detection limit was 0.25ng/mL. These results suggest that this assay is a rapid, simple and sensitive method. On the other hand, the mean±SD clearance of carvedilol was 1.10 ±0.541L/hr/kg and 0.611±0.320L/hr/kg in 4 male volunteers who received 10mg carvedilol orally and in 21 inpatients who received carvedilol b.i.d. for at least a week, respectively. Our findings indicated that even though the carvedilol concentrations increased depending on the dose, the individual variations among individuals were large.
