New RP‐HPLC Method with UV‐Detection for the Determination of Carvedilol in Human Serum

Abstract

Carvedilol has been used as an antihypertensive drug and also possesses antioxidant and antiproliferative effects. A simple and sensitive analytical method for carvedilol in human serum by using high performance liquid chromatography (HPLC) was developed. The method employs a liquid‐liquid extraction for isolation and sample concentration followed by reversed phase liquid chromatography (RPLC) analysis using ultraviolet (UV) detection at 238 nm. Analytes were extracted from serum samples, that were previously mixed with 300 µL of 0.1 N sodium hydroxide solution into an n‐hexane, dichloromethane (7∶3) solvent system. The mobile phase was made of acetonitrile, 15 mM orthophosphoric acid (37∶63), and 0.25% v/v of triethylamine, with a flow rate of 1 mL/min. Serum samples containing the carvedilol and internal standard, amitriptyline were eluted through a C8, Kromasil KR 100 5C8 column. Retention times of carvedilol and amitriptyline were 6.10 min and 8.44 min, respectively. The intra day and inter day coefficient of variation and percent error values of the assay method were less than 5%. The calibration curve was linear over a concentration range of 5–500 ng/mL. The extraction recovery of carvedilol is more than 75%. The validated method was applied to a pharmacokinetic study of carvedilol in human serum following the administration of a single carvedilol tablet (6.25 mg). Such a method would be ideally suitable for estimation of the drug for pharmacokinetic studies in human volunteers after oral administration of a single or multiple dosage(s) of carvedilol.