title: Determination of benidipine in human plasma using liquid chromatography-tandem mass spectrometry.
abstract: We developed a method for determining benidipine, a dihydropyridine analogue calcium-channel blocker, in plasma using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Benidipine and benidipine-d5, an internal standard, were extracted from plasma using diethyl ether in the presence of 5M NaOH. After drying the organic layer, the residue was reconstituted in acetonitrile and injected onto a reversed-phase C18 column. The isocratic mobile phase (acetonitrile-5mM ammonium acetate, 90:10, v/v) was eluted at 0.2 ml/min. The ion transitions monitored in multiple reaction-monitoring mode were m/z 506-174 for benidipine and m/z 511-179 for the internal standard. The coefficient of variation of the assay precision was less than 13%, and the accuracy exceeded 92%, except at the limit of quantification, 0.05 ng/ml with 1ml of plasma, when it was 85%. This method was used to measure the benidipine concentration in plasma from healthy subjects after a single 4-mg oral dose of benidipine. This method is a very simple, sensitive, and accurate way to determine the plasma benidipine concentration.
authors.affiliation: Department of Pharmacology and Pharmacogenomics Research Center, Inje University College of Medicine, Busan, Republic of Korea.
authors.forename: Wonku
authors.initials: W
authors.lastname: Kang
authors.forename: Hwi-Yeol
authors.initials: HY
authors.lastname: Yun
authors.forename: Kwang-Hyeon
authors.initials: KH
authors.lastname: Liu
authors.forename: Kwang-Il
authors.initials: KI
authors.lastname: Kwon
authors.forename: Jae-Gook
authors.initials: JG
authors.lastname: Shin
mesh_terms: D019540:Area Under Curve; D002121:Calcium Channel Blockers / Q000097:blood* / Q000493:pharmacokinetics; D002853:Chromatography, Liquid / Q000379:methods*; D004095:Dihydropyridines / Q000097:blood* / Q000493:pharmacokinetics; D006801:Humans; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D002121:Calcium Channel Blockers; D004095:Dihydropyridines; C061004:benidipine