title: A sensitive LC-MS/MS method for the quantification of febuxostat in human plasma and its pharmacokinetic application.
abstract: An improved, simple and highly sensitive LC-MS/MS method has been developed and validated for quantification of febuxostat with 100 μL human plasma using febuxostat-d7 as an internal standard (IS) according to regulatory guidelines. The analyte and IS were extracted from human plasma via liquid-liquid extraction using diethyl ether. The chromatographic separation was achieved on a Zorbax C18 column using a mixture of acetonitrile and 5 mm ammonium formate (60:40, v/v) as the mobile phase at a flow rate of 0.5 mL/min. The total run time was 5.0 min and the elution of febuxostat and IS occurred at 1.0 and 1.5 min, respectively. A linear response function was established for the range of concentrations 1-6000 ng/mL (r > 0.99). The precursor to product ion transitions monitored for febuxostat and IS were m/z 317.1 → 261.1 and 324.2 → 262.1, respectively. The intra- and inter-day precisions (%RSD) were within 1.29-9.19 and 2.85-7.69%, respectively. The proposed method was successfully applied to pharmacokinetic studies in humans.
authors.affiliation: Bioanalytical Department, Apotex Research Pvt. Ltd, Bangalore, India; Department of Chemistry, Sri Krishna Devaraya University, Anantapur, 515055, India.
authors.forename: Venkata Rami Reddy
authors.initials: VR
authors.lastname: Vaka
authors.forename: Jaswanth Kumar
authors.initials: JK
authors.lastname: Inamadugu
authors.forename: Nageswara Rao
authors.initials: NR
authors.lastname: Pilli
authors.forename: Mullangi
authors.initials: M
authors.lastname: Ramesh
authors.forename: Hussain Reddy
authors.initials: HR
authors.lastname: Katreddi
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D000069465:Febuxostat; D006074:Gout Suppressants / Q000097:blood*; D006801:Humans; D057230:Limit of Detection; D059625:Liquid-Liquid Extraction / Q000379:methods; D008297:Male; D053719:Tandem Mass Spectrometry / Q000379:methods; D013844:Thiazoles / Q000097:blood*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors
chemical_list: D006074:Gout Suppressants; D013844:Thiazoles; D000069465:Febuxostat; D014969:Xanthine Oxidase
keywords: febuxostat; human plasma; method validation; LC-MS/MS; pharmacokinetics