A Highhyphen;Performance Liquid Chromatographic Method for the Determination of Encainide and Its Major Metabolites in Urine and Serum Using Solidhyphen;Phase Extraction

摘要

Summary: A high-performance liquid chromatography (HPLC) procedure used to quantitate encainide and two of its active metabolites,O-desmethylencainide (ODE) and 3-methoxy-O-desmethylencainide (MODE), is described. All three compounds were simultaneously extracted from urine and serum using an octyl (C-8) solid-phase extraction column. The compounds were then separated by reverse-phase HPLC on a cyanopropylsilane column using ultraviolet detection at 260 nm. Serum samples were quantified over a concentration range of 25ndash;400 ng/ml and urine over a range of 150ndash;10,000 ng/ml. Total run time for the assay was 12 min. Within-day and between-day precision and relative error were 10percnt; in serum and 13percnt; in urine for all three compounds. The lower limit of quantitation was 10 ng/ml for encainide and ODE and 15 ng/ml for MODE. This HPLC procedure represents a quick and reliable method of measuring encainide and its major metabolites in both urine and serum, making the assay applicable as an aid for therapeutic drug monitoring of patients receiving encainide therapy.