title: Determination of adefovir in human plasma by liquid chromatography/tandem mass spectrometry: application to a pharmacokinetic study.
abstract: A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated to determine the concentrations of adefovir [9-(2-phosphonylmethoxyethyl)adenine, PMEA] in human plasma. After one-step protein precipitation of plasma samples by methanol, adefovir was analyzed by LC/MS/MS using positive electrospray ionization. Chromatography was performed on a C18 column. The extraction recoveries of adefovir were found to be 85.1-89.3%. Adefovir was stable under routine laboratory conditions. A minimal matrix effect resulting in a slight ionization enhancement of adefovir (<10.9%) was observed, which did not markedly affect the behavior of the calibrations curves and accuracy and precision data. The method had a chromatographic run time of 7.8 min and a linear calibration curve over the concentration range 1.5-90 ng/mL for adefovir. The lower limit of quantification of the method was 1.5 ng/mL. The intra- and inter-day precision was less than 8.4%. These results indicated that this LC/MS/MS method has high selectivity and efficiency, and acceptable accuracy, precision and sensitivity. The validated LC/MS/MS method has been successfully used in a pharmacokinetic study in healthy volunteers treated with oral adefovir dipivoxil at 10 and 20 mg.
authors.affiliation: Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510080, China.
authors.forename: Hui-Chang
authors.initials: HC
authors.lastname: Bi
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Zhong
authors.forename: Shufeng
authors.initials: S
authors.lastname: Zhou
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Huang
mesh_terms: D000225:Adenine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D000284:Administration, Oral; D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004341:Drug Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D063065:Organophosphonates / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D010599:Pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D063065:Organophosphonates; C053001:adefovir; D000225:Adenine