title: A validated method for quantifying entecavir in biological matrices and its application in a pharmacokinetic study in rats and dogs.
abstract: A sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method that uses ganciclovir as an internal standard (IS) has been developed and validated for quantifying entecavir in rat and dog plasma. Following solid-phase extraction (SPE), the analytes were separated on an Inertsil® ODS-3 (5 μm, 150 mm × 2.1 mm i.d.) column and analyzed in selected ion monitoring (SIM) mode with a positive electrospray ionization (ESI) source using the [M+H]+ ions, 278.1 for entecavir and 256.0 for ganciclovir. The method was validated over the concentration range of 0.01-9 μg/mL for entecavir. All precisions (RSD) within and between batches were less than 10%, and accuracies ranged from 98.1 to 102.5%. The lower limit of quantification was 0.01 µg/mL. The extraction recovery averaged 93.9-96.7%. The validated method was used for a pharmacokinetic study of entecavir in rats and dogs. The following pharmacokinetic parameters were obtained for rats and dogs, respectively: the area under the plasma concentration vs. time curves from time 0 to 24 h (AUC0-24) were 15.4 ± 4.5 and 23.4 ± 7.2 μg∙h/mL; the mean maximum plasma concentration (Cmax) were 2.4 ± 0.8 and 5.0 ± 0.9 μg/mL; the mean time to reach the maximum plasma concentrations (Tmax) were 1.7 ± 0.7 and 1.5 ± 0.4 h; and the mean elimination half-life (t1/2) were 5.3 ± 1.4 and 3.8 ± 1.3 h.
authors.affiliation: Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing, P. R. China.
authors.forename: X
authors.initials: X
authors.lastname: Huang
authors.affiliation: Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing, P. R. China.
authors.forename: Z-Z
authors.initials: ZZ
authors.lastname: Jiang
authors.affiliation: Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing, P. R. China.
authors.forename: W-W
authors.initials: WW
authors.lastname: Tang
authors.affiliation: Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing, P. R. China.
authors.forename: Y
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Jiangsu Center for Drug Screening, China Pharmaceutical University, Nanjing, P. R. China.
authors.forename: L-Y
authors.initials: LY
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Drug Quality Control and Pharmacovigilance (China Pharmaceutical University), Ministry of Education, Nanjing, P. R. China.
authors.forename: Z-J
authors.initials: ZJ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002853:Chromatography, Liquid / Q000379:methods*; D004285:Dogs; D006147:Guanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D006207:Half-Life; D057230:Limit of Detection; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000998:Antiviral Agents; C413685:entecavir; D006147:Guanine