Determination of verapamil and norverapamil in human biological material. Investigation of plasma concentrations after oral administration of two different verapamil formulations.
A method for the simultaneous determination of the cardiovascular agent verapamil and its major metabolite norverapamil in human plasma is described. Analysis is performed after alkaline extraction with n-heptane by subsequent ion-paired high performance liquid chromatographic (HPLC) separation, and direct fluorimetric measurement of both compounds (lambda maxex. = 278 nm, lambda maxem. = 320 nm). The sensitivity of the procedure (detection limit less than 1 ng/ml) is suitable for pharmacokinetic studies after therapeutic doses. The applicability of the method was tested by performing a clinical study. Plasma concentrations of two verapamil formulations for oral administration were examined. The active metabolite norverapamil was included in the investigation.
Horne
C
C
Pharmakologisches Institut für Naturwissenschaftler der Johann Wolfgang Goethe-Universität, Frankfurt/Main, Fed. Rep. of Germany.
Spahn
H
H
Mutschler
E
E
Knauf
H
H
D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D008297:Male; D013050:Spectrometry, Fluorescence; D014700:Verapamil / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood*
C016904:norverapamil; D014700:Verapamil