title: Direct quantitative determination of amlodipine enantiomers in urine samples for pharmacokinetic study using on-line coupled isotachophoresis-capillary zone electrophoresis separation method with diode array detection.
abstract: The present work illustrates possibilities of column-coupling capillary electrophoresis (CE-CE) combined with chiral selector (2-hydroxypropyl-beta-cyclodextrin, HP-beta-CD) and fiber-based diode array detection (DAD) for the direct quantitative enantioselective determination of trace drug (amlodipine, AML) in biological multicomponent ionic matrices (human urine). Capillary isotachophoresis (ITP) served as an ideal injection technique in CE-CE. Moreover, the ITP provided an effective on-line sample pretreatment prior to the capillary zone electrophoresis (CZE) separation. Enhanced separation selectivity due to the combination of different separation mechanisms (ITP vs. CZE-HP-beta-CD) enabled to obtain pure zones of the analytes, suitable for their detection and quantitation. The DAD, unlike single wavelength UV detection, enabled to characterize the purity (i.e. spectral homogeneity) of the analytes zones. A processing of the raw DAD spectra (the background correction and smoothing procedure) was essential when a trace analyte signal was evaluated. Obtained results indicated pure (i.e. spectrally homogeneous) zones of interest confirming effective ITP-CZE separation process. The proposed ITP-CZE-DAD method was characterized by favorable performance parameters (sensitivity, linearity, precision, recovery, accuracy, robustness, selectivity) and successfully applied to an enantioselective pharmacokinetic study of AML.
authors.affiliation: Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Odbojárov 10, SK-832 32 Bramtislava, Slovak Republic. mikus@fpharm.uniba.sk
authors.forename: Peter
authors.initials: P
authors.lastname: Miks
authors.forename: Katarína
authors.initials: K
authors.lastname: Maráková
authors.forename: Jozef
authors.initials: J
authors.lastname: Marák
authors.forename: Igor
authors.initials: I
authors.lastname: Nemec
authors.forename: Iva a
authors.initials: Ia
authors.lastname: Valásková
authors.forename: Emil
authors.initials: E
authors.lastname: Havránek
mesh_terms: D017311:Amlodipine / Q000493:pharmacokinetics / Q000652:urine*; D004586:Electrophoresis / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D008297:Male; D009862:Online Systems; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D017311:Amlodipine