HPLC/fluorometric detection of carvedilol in real human plasma samples using liquid-liquid extraction

Abstract

A simple, rapid and sensitive high-performance liquid chromatography (HPLC) method has been developed to quantify carvedilol in human plasma using an isocratic system with fluorescence detection. The method included a single-step liquid-liquid extraction with diethylether and ethylacetate mixture (3: 1, v/v). HPLC separation was carried out by reversed-phase chromatography with a mobile phase composed of 20 mM phosphate buffer (pH 7)-acetonitrile (65: 35, v/v), pumped at a flow rate of 1.0 mL/min. Fluorescence detection was performed at 240 nm (excitation) and 330 nm (emission). The calibration curve for carvedilol was linear from 10 to 250 ng/mL. Intra- and interday precision values for carvedilol in human plasma were <4.93%, and accuracy (relative error) was better than 4.71%. The analytical recovery of carvedilol from human plasma averaged out to 91.8%. The limits of detection and quantification of carvedilol were 3.0 and 10 ng/mL, respectively. Also, the method was successfully applied to three patients with hypertension who had been given an oral tablet of 25 mg carvedilol.