Liquid Chromatography Tandem Mass Spectrometry Method For Determination of Febuxostat in Human Plasma To Support A Bioequivalence Study - Liquid Chromatography Tandem Mass Spectrometry Method For Determination of Febuxostat in Human Plasma To Support A Bioequivalence Study - Open Access Pub

A reliable, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) assay has been proposed for the determination of febuxostat in human plasma using indomethacin as the internal standard (IS). The analyte and IS were extracted from 200 μL of human plasma via liquid-liquid extraction using methyl tert-butyl ether. Chromatography was performed on Hypurity C18 (100 mm × 4.6 mm, 5 μm) column under isocratic conditions. Detection of analyte and IS was done by tandem mass spectrometry, operating in negative ionization and multiple reaction monitoring mode. The deprotonated precursor to product ion transitions monitored for febuxostat and indomethacin were m/z 315.1 →271.0 and 356.1→312.0 respectively. The limit of detection (LOD) and limit of quantitation (LOQ) of the method were 0.0025 μg/mL and 0.05 μg/mL respectively. The linear dynamic range validated for febuxostat was 0.05-6.00 μg/mL. The intra-batch and inter-batch precision (% CV) was ≤ 7.1 % while the mean extraction recovery was > 87 % for febuxostat across quality control levels. The method was successfully applied to a bioequivalence study of 80 mg febuxostat tablet formulation in 14 healthy Indian male subjects under fasting and fed condition. The reproducibility in the measurement of study data was demonstrated by reanalysis of 110 incurred samples. DOI10.14302/issn.2328-0182.japst-12-173 Febuxostat FEB2 is a non-purine urate lowering drug, used in the treatment and management of hyperuricemia and gout 1, 2, 3. Gout is a common disorder characterized by hyperuricemia and by acute and chronic consequences of urate crystal deposition in the joints and periarticular tissues 4 FEB is a selective inhibitor of both the oxidised and reduced forms of xanthine oxidase, the enzyme that catalyzes the synthesis of uric acid from hypoxanthine and xanthine4. It was approved by the US Food and Drug Administration for the management of hyperuricemia in adults with gout in February 2009 5. FEB is well absorbed from the gastrointestinal tract after oral administration with an oral bioavailability of 84 % and the time to reach peak plasma concentration is about 1 h in healthy volunteers 2, 6. The half life of FEB is 5-8 h and the volume of distribution ranges from 29 to 751 L/kg at steady state for oral dose of 10-300 mg. It is highly protein bound (99 %), primarily to albumin and gets extensively metabolized via phase II (glucuronidation) and phase I (oxidation) in the liver followed by excretion of metabolites in the urine and faeces 1, 7, 8. FEB has been determined in bulk and