{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T10:44:35Z","timestamp":1771670675541,"version":"3.50.1"},"reference-count":12,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2025,2,19]],"date-time":"2025-02-19T00:00:00Z","timestamp":1739923200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["analyticalsciencejournals.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Biomedical Chromatography"],"published-print":{"date-parts":[[2025,4]]},"abstract":"<jats:title>ABSTRACT<\/jats:title><jats:p>Filgotinib (FLG) is a Janus kinase 1 inhibitor and is metabolized to an active metabolite, GS\u2010829845. There is no report on the method for simultaneous quantification of FLG and GS\u2010829845 in clinical samples. We developed a liquid chromatography\u2013tandem mass spectrometry method for simultaneous determination of FLG and GS\u2010829845 in patient plasma. FLG and GS\u2010829845 were extracted from an aliquot of 50\u2009\u03bcL of human plasma by simple deproteinization using methanol. Chromatographic separation was performed using a Shim\u2010pack Scepter C18\u2010120 column with a combined mobile phase of water and methanol containing 0.1% formic acid and gradient elution at a flow rate of 0.2\u2009mL\/min. Detection was performed by positive electrospray ionization using a QTRAP 4500 mass spectrometer. The method was validated in the concentration range of 2.5\u201350\u2009ng\/mL for FLG and 250\u20135000\u2009ng\/mL for GS\u2010829845. Intra\u2010 and inter\u2010day assay accuracy and precision were within 11.4% and 13.9%, respectively. Recoveries and matrix effects were consistent and reproducible. This developed and fully validated method is simple, rapid, and cost\u2010effective and was used successfully for therapeutic drug monitoring in a patient with rheumatoid arthritis.<\/jats:p>","DOI":"10.1002\/bmc.70030","type":"journal-article","created":{"date-parts":[[2025,2,19]],"date-time":"2025-02-19T07:25:32Z","timestamp":1739949932000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Simultaneous Quantification of Filgotinib and Its Active Metabolite in Human Plasma Using Liquid Chromatography\u2013Tandem Mass Spectrometry: Validation and Clinical Application"],"prefix":"10.1002","volume":"39","author":[{"given":"Takahiro","family":"Ito","sequence":"first","affiliation":[{"name":"School of Pharmaceutical Sciences Wakayama Medical University  Wakayama Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1511-7725","authenticated-orcid":false,"given":"Manabu","family":"Suno","sequence":"additional","affiliation":[{"name":"School of Pharmaceutical Sciences Wakayama Medical University  Wakayama Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Minae","family":"Shintani","sequence":"additional","affiliation":[{"name":"School of Pharmaceutical Sciences Wakayama Medical University  Wakayama Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ayaka","family":"Iwata","sequence":"additional","affiliation":[{"name":"School of Pharmaceutical Sciences Wakayama Medical University  Wakayama Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takao","family":"Fujii","sequence":"additional","affiliation":[{"name":"Department of Rheumatology and Clinical Immunology Wakayama Medical University  Wakayama Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kazuo","family":"Matsubara","sequence":"additional","affiliation":[{"name":"School of Pharmaceutical Sciences Wakayama Medical University  Wakayama Japan"},{"name":"Department of Pharmacy Wakayama Medical University Hospital  Wakayama Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,2,19]]},"reference":[{"key":"e_1_2_7_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jchromb.2020.122195"},{"key":"e_1_2_7_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/cpdd.659"},{"key":"e_1_2_7_4_1","doi-asserted-by":"publisher","DOI":"10.1002\/bmc.4802"},{"key":"e_1_2_7_5_1","doi-asserted-by":"publisher","DOI":"10.5599\/admet.796"},{"key":"e_1_2_7_6_1","doi-asserted-by":"publisher","DOI":"10.1111\/cts.13152"},{"key":"e_1_2_7_7_1","doi-asserted-by":"publisher","DOI":"10.1136\/ard.2006.054205"},{"key":"e_1_2_7_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.talanta.2019.120450"},{"key":"e_1_2_7_9_1","doi-asserted-by":"publisher","DOI":"10.1111\/bcp.15239"},{"key":"e_1_2_7_10_1","doi-asserted-by":"publisher","DOI":"10.1007\/s40262\u2010022\u201001129\u2010y"},{"key":"e_1_2_7_11_1","doi-asserted-by":"publisher","DOI":"10.1007\/s40262\u2010015\u20100240\u2010z"},{"key":"e_1_2_7_12_1","unstructured":"U.S. Food and Drug Administration.2018. \u201cGuidance for Bioanalytical Method Validation.\u201dhttps:\/\/www.fda.gov\/media\/70858\/download."},{"key":"e_1_2_7_13_1","doi-asserted-by":"publisher","DOI":"10.1055\/a\u20101141\u20103475"}],"container-title":["Biomedical Chromatography"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/analyticalsciencejournals.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/bmc.70030","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T00:07:27Z","timestamp":1760054847000},"score":1,"resource":{"primary":{"URL":"https:\/\/analyticalsciencejournals.onlinelibrary.wiley.com\/doi\/10.1002\/bmc.70030"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,2,19]]},"references-count":12,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2025,4]]}},"alternative-id":["10.1002\/bmc.70030"],"URL":"https:\/\/doi.org\/10.1002\/bmc.70030","archive":["Portico"],"relation":{},"ISSN":["0269-3879","1099-0801"],"issn-type":[{"value":"0269-3879","type":"print"},{"value":"1099-0801","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,2,19]]},"assertion":[{"value":"2024-10-24","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-02-07","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-02-19","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e70030"}}