The determination of labetalol in plasma by high-performance liquid chromatography using fluorescence detection

A sensitive and specific assay for labetalol is described. The method employed is reverse phase high-performance liquid chromatography (HPLC) with fluorescence detection. Using 1 ml of plasma, the limit of detection of the assay was 8 ng/ml and the coefficient of variation over a typical calibration range is 5.5%. Various drugs that might be coadministered with labetalol are shown not to interfere in the assay. The method has been employed to study the pharmacokinetics of labetalol following intravenous and oral administration.