Enantioselective determination of doxazosin in human plasma by liquid chromatography-tandem mass spectrometry using ovomucoid chiral stationary phase.
An enantioselective and sensitive method was developed and validated for determination of doxazosin enantiomers in human plasma by liquid chromatography-tandem mass spectrometry. The enantiomers of doxazosin were extracted from plasma using ethyl ether/dichloromethane (3/2, v/v) under alkaline conditions. Baseline chiral separation was obtained within 9 min on an ovomucoid column using an isocratic mobile phase of methanol/5mM ammonium acetate/formic acid (20/80/0.016, v/v/v) at a flow rate of 0.60 mL/min. Acquisition of mass spectrometric data was performed in multiple reaction monitoring mode, using the transitions of m/z 452-->344 for doxazosin enantiomers, and m/z 384-->247 for prazosin (internal standard). The method was linear in the concentration range of 0.100-50.0 ng/mL for each enantiomer using 200 microL of plasma. The lower limit of quantification (LLOQ) for each enantiomer was 0.100 ng/mL. The intra- and inter-assay precision was 5.0-11.1% and 5.7-7.6% for R-(-)-doxazosin and S-(+)-doxazosin, respectively. The accuracy was 97.4-99.5% for R-(-)-doxazosin and 96.8-102.8% for S-(+)-doxazosin. No chiral inversion was observed during the plasma storage, preparation and analysis. The method proved adequate for enantioselective pharmacokinetic studies of doxazosin after oral administration of therapeutic doses of racemic doxazosin.
Liu
Ke
K
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, PR China.
Zhong
Dafang
D
Chen
Xiaoyan
X
D058668:Adrenergic alpha-1 Receptor Antagonists / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D002853:Chromatography, Liquid / Q000379:methods*; D017292:Doxazosin / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D004355:Drug Stability; D006801:Humans; D016018:Least-Squares Analysis; D010059:Ovomucin / Q000737:chemistry*; D011224:Prazosin / Q000032:analysis / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*
D058668:Adrenergic alpha-1 Receptor Antagonists; D010059:Ovomucin; D017292:Doxazosin; D011224:Prazosin