{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,23]],"date-time":"2026-08-23T17:47:35Z","timestamp":1787507255945,"version":"build-2736575974"},"reference-count":26,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,1,17]],"date-time":"2025-01-17T00:00:00Z","timestamp":1737072000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004488","name":"Croatian Science Foundation","doi-asserted-by":"publisher","award":["HRZZ-DOK-2021-02-7922"],"award-info":[{"award-number":["HRZZ-DOK-2021-02-7922"]}],"id":[{"id":"10.13039\/501100004488","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004488","name":"Croatian Science Foundation","doi-asserted-by":"publisher","award":["KK.01.1.1.02.0021"],"award-info":[{"award-number":["KK.01.1.1.02.0021"]}],"id":[{"id":"10.13039\/501100004488","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100008530","name":"European Regional Development Fund","doi-asserted-by":"publisher","award":["HRZZ-DOK-2021-02-7922"],"award-info":[{"award-number":["HRZZ-DOK-2021-02-7922"]}],"id":[{"id":"10.13039\/501100008530","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100008530","name":"European Regional Development Fund","doi-asserted-by":"publisher","award":["KK.01.1.1.02.0021"],"award-info":[{"award-number":["KK.01.1.1.02.0021"]}],"id":[{"id":"10.13039\/501100008530","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmaceuticals"],"abstract":"<jats:p>Background\/Objectives: Janus kinase inhibitors open new horizons for small-molecule drugs in treating inflammatory bowel disease, with ritlecitinib demonstrating significant efficacy in clinical trials for ulcerative colitis and Crohn\u2019s disease. Ritlecitinib, a second-generation JAK3 inhibitor, is a novel therapeutic agent for alopecia areata and other autoimmune conditions. Methods: A new stability-indicating UHPLC-DAD-MS\/MS method was developed, validated, and applied for a forced degradation study of ritlecitinib under ICH guidelines. Results: The method demonstrated high specificity, sensitivity (LOD: 0.04 \u00b5g\/mL; LOQ: 0.14 \u00b5g\/mL), precision (RSD \u2264 0.15%), and accuracy (99.9\u2013100.3%). Forced degradation studies under acidic, basic, oxidative, thermal, and photolytic conditions revealed four novel degradation products. Basic degradation followed second-order kinetics, while oxidative degradation followed zero-order kinetics. Conclusions: The validated method reliably characterized ritlecitinib\u2019s stability and degradation products, providing essential data for optimizing formulation, determining proper storage conditions, anticipating drug\u2013excipient interactions, and ensuring quality control. The eco-friendliness and applicability of the developed forced degradation procedure were evaluated using various green and blue metric tools. Incorporating green analytical principles underscores its potential for sustainable pharmaceutical analysis.<\/jats:p>","DOI":"10.3390\/ph18010124","type":"journal-article","created":{"date-parts":[[2025,1,17]],"date-time":"2025-01-17T10:27:58Z","timestamp":1737109678000},"page":"124","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["The Stability-Indicating Ultra High-Performance Liquid Chromatography with Diode Array Detector and Tandem Mass Spectrometry Method Applied for the Forced Degradation Study of Ritlecitinib: An Appraisal of Green and Blue Metrics"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6634-6130","authenticated-orcid":false,"given":"Jelena","family":"Kova\u010di\u0107","sequence":"first","affiliation":[{"name":"Department of Pharmaceutical Analysis, Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1695-6950","authenticated-orcid":false,"given":"Daniela","family":"Amid\u017ei\u0107 Klari\u0107","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Analysis, Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nik\u0161a","family":"Turk","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, University Hospital Centre, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3758-4540","authenticated-orcid":false,"given":"\u017deljko","family":"Krznari\u0107","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, University Hospital Centre, 10000 Zagreb, Croatia"},{"name":"School of Medicine, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emma","family":"Riordan","sequence":"additional","affiliation":[{"name":"School of Pharmacy, University College Cork, T12 YT20 Cork, Ireland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ana","family":"Mornar","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Analysis, Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,1,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"107059","DOI":"10.1016\/j.phrs.2024.107059","article-title":"Properties of FDA-approved Small Molecule Protein Kinase Inhibitors: A 2024 Update","volume":"200","author":"Roskoski","year":"2024","journal-title":"Pharmacol. 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