title: A high-performance liquid chromatographic method for the determination of encainide and its major metabolites in urine and serum using solid-phase extraction.
abstract: 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 25-400 ng/ml and urine over a range of 150-10,000 ng/ml. Total run time for the assay was less than 12 min. Within-day and between-day precision and relative error were less than 10% in serum and less than 13% 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.
authors.affiliation: Department of Clinical Pharmacy, University of Tennessee, Memphis 38163.
authors.forename: D J
authors.initials: DJ
authors.lastname: Kazierad
authors.forename: T J
authors.initials: TJ
authors.lastname: Hoon
authors.forename: M B
authors.initials: MB
authors.lastname: Bottorff
mesh_terms: D000813:Anilides / Q000032:analysis* / Q000097:blood / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D016700:Encainide; D006801:Humans; D007202:Indicators and Reagents; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000813:Anilides; D007202:Indicators and Reagents; D016700:Encainide