title: Simultaneous determination of verapamil and norverapamil in biological samples by high-performance liquid chromatography using ultraviolet detection.
abstract: In this paper we develop an high-performance liquid chromatographic method with ultraviolet detection for the determination of verapamil and its primary metabolite norverapamil in biological samples. Both compounds, as well as the internal standard, imipramine, were extracted from alkalinised blood, with n-hexane-isobutyl alcohol, back-extracted into 0.01 M phosphoric acid and determined using a reversed-phase column and ultraviolet monitoring at 210 nm. The average coefficient of variation obtained over the concentration range of 1-1000 ng/ml is about 3%. The detection limit is below 5 ng/ml for both compounds, and extraction recoveries close to 80%. The method was applied to a pharmacokinetic study of the drug and its active metabolite and used to analyse blood samples from verapamil treated rabbits.
authors.affiliation: Department of Analytical Chemistry, Veterinary Faculty, University of Zaragoza, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Garcia
authors.forename: J J
authors.initials: JJ
authors.lastname: Aramayona
authors.forename: M A
authors.initials: MA
authors.lastname: Bregante
authors.forename: L J
authors.initials: LJ
authors.lastname: Fraile
authors.forename: C
authors.initials: C
authors.lastname: Solans
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000097:blood* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D011817:Rabbits; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet; D014700:Verapamil / Q000031:analogs & derivatives* / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D002121:Calcium Channel Blockers; C016904:norverapamil; D014700:Verapamil