title: Direct determination of celiprolol in human urine using on-line coupled ITP-CZE method with fiber-based DAD.
abstract: The present work illustrated possibilities of column-coupling electrophoresis combined with DAD for the direct quantitative determination of trace drug (celiprolol, CEL) in clinical human urine samples. ITP, on-line coupled with CZE, served as an ideal injection technique (high sample load capacity, narrow and sharp drug zone). Moreover, the ITP provided an effective on-line sample pretreatment (preseparation, purification and preconcentration of the drug) producing analyte zone suitable for its direct detection and quantitation in CZE stage. Spectral DAD in comparison with single wavelength ultraviolet detection enhanced value of analytical information (i) verifying purity (i.e., spectral homogeneity) of drug zone (according to differences in spectrum profiles when compared tested and reference drug spectra) and (ii) indicating zones/peaks with spectra similar to the drug spectrum (potential structurally related metabolites). The characterization of trace analyte signals superposed on the baseline noise was more definite thanks to the application of background correction and smoothing procedure to the raw DAD spectra (producing relevant spectral response). The proposed ITP-CZE-DAD method was characterized by favorable performance parameters for CEL in urine matrices {e.g., the lower limit of quantification was 9.7 ng/mL, RSD and relative error of the determinations were lower than 3% (precision) and 1% (accuracy), respectively, analyte peak exhibited spectral homogeneity (reflecting separation selectivity), separation efficiency was 84,500 theoretical plates} and successfully applied in a trial pharmacokinetic study of CEL.
authors.affiliation: Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Slovak Republic. mikus@fpharm.uniba.sk
authors.forename: Peter
authors.initials: P
authors.lastname: Mikus
authors.forename: Katarína
authors.initials: K
authors.lastname: Maráková
authors.forename: Jozef
authors.initials: J
authors.lastname: Marák
authors.forename: Alexandra
authors.initials: A
authors.lastname: Planková
authors.forename: Iva
authors.initials: I
authors.lastname: Valásková
authors.forename: Emil
authors.initials: E
authors.lastname: Havránek
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000652:urine*; D002021:Buffers; D017272:Celiprolol / Q000652:urine*; D004586:Electrophoresis / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000379:methods*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000319:Adrenergic beta-Antagonists; D002021:Buffers; D017272:Celiprolol