title: Sensitive and specific LC-MS/MS method for the simultaneous measurements of viramidine and ribavirin in human plasma.
abstract: Viramidine is a prodrug of ribavirin. To facilitate pharmacokinetics studies of viramidine in man, a sensitive and specific LC-MS/MS method for the simultaneous analyses of viramidine and ribavirin in human plasma was developed and validated. The method involved the addition of [13C]viramidine and [13C]ribavirin as internal standards, protein precipitation with acetonitrile, HPLC separation, and quantification by MS/MS system using positive electrospray ionization in the multiple reaction monitoring mode (MRM). The precursor-->product ion transitions were monitored at 245-->113, 250-->113, 244-->112, and 249-->112 for ribavirin, [13C]ribavirin, viramidine, and [13C]viramidine, respectively. The calibration curves for viramidine and ribavirin were linear over a concentration range of 1-1000 ng/mL. For both viramidine and ribavirin, the lower limit of quantification (LLOQ) was 1 ng/mL. For viramidine, intra- and inter-day analyses of QC samples at 1, 5, 250, and 1000 ng/mL indicated good precision (%CV between 1.0 and 7.0%) and accuracy (%bias between -4.3 and 5.2%). For ribavirin, intra- and inter-day analyses of QC samples at 1, 5, 250, and 1000 ng/mL indicated similar precision (%CV between 0.8 and 8.3%) and accuracy (%bias between -5.8 and 9.4%). Both viramidine and ribavirin were stable in human plasma stored at room temperature for at least 3 h, 4 degrees C for at least 6 h, and for at least three freeze-thaw cycles. This accurate and highly specific assay provides a useful method for evaluating the pharmacokinetics of viramidine and ribavirin in man following administration of viramidine.
authors.affiliation: Valeant Research & Development, 3300 Hyland Avenue, Costa Mesa, CA 92626, USA.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Liu
authors.forename: Christine
authors.initials: C
authors.lastname: Xu
authors.forename: Rongzi
authors.initials: R
authors.lastname: Yan
authors.forename: Charmaine
authors.initials: C
authors.lastname: Lim
authors.forename: Li-Tain
authors.initials: LT
authors.lastname: Yeh
authors.forename: Chin-chung
authors.initials: CC
authors.lastname: Lin
mesh_terms: D000998:Antiviral Agents / Q000097:blood* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D012254:Ribavirin / Q000031:analogs & derivatives* / Q000097:blood* / Q000493:pharmacokinetics; D012680:Sensitivity and Specificity
chemical_list: D000998:Antiviral Agents; D012254:Ribavirin; C026956:taribavirin