{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,19]],"date-time":"2025-10-19T16:12:02Z","timestamp":1760890322654},"reference-count":39,"publisher":"Oxford University Press (OUP)","issue":"4","license":[{"start":{"date-parts":[[2021,1,28]],"date-time":"2021-01-28T00:00:00Z","timestamp":1611792000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2021,7,7]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background<\/jats:title><jats:p>Hydroxychloroquine (HCQ) blood levels are used to monitor efficacy, safety, and patient adherence during treatment. Oral fluid has emerged as an alternative noninvasive, easily accessible, and low-complexity matrix for drug monitoring. However, there is no analytical method to measure HCQ in oral fluid. Therefore, we developed and validated an ultra-high-performance liquid chromatography-tandem mass (UHPLC-MS\/MS) method for the measurement of HCQ and its main metabolites in oral fluid and compared to whole blood.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Ten microliters of matrices were used for sample preparation by protein precipitation with acetonitrile followed by online solid phase extraction. The validation process included assessment of lower limit of quantification, linearity, precision, recovery, matrix effect, interferences assessment, carryover, and sample dilution validation.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The lower limit of quantification was 50\u2009ng\/mL for HCQ and metabolites in both oral fluid and whole blood. The calibration curve was linear from 50 to 2000\u2009ng\/mL (r2 = 0.999). The coefficient of variation for precision assay was 1.2% to 9.7% for intraday and 1.1% to 14.2% for interday for both HCQ and metabolites in oral fluid and whole blood samples at 150, 750, and 1250\u2009ng\/mL. The recovery was 85.3% to 118.5% for 150, 750, and 1250\u2009ng\/mL of HCQ and metabolites in both oral fluid and whole blood. Dilution factor up to 5-fold was validated for concentrations higher than the upper limit of quantification.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>The validated method is specific, precise, and accurate to determine the analytical range for therapeutic monitoring of HCQ and its main metabolites in oral fluid and blood.<\/jats:p><\/jats:sec>","DOI":"10.1093\/jalm\/jfab031","type":"journal-article","created":{"date-parts":[[2021,4,6]],"date-time":"2021-04-06T15:10:29Z","timestamp":1617721829000},"page":"868-880","source":"Crossref","is-referenced-by-count":5,"title":["UHPLC-MS\/MS Method for Determination of Hydroxychloroquine and Its Main Metabolites in Oral Fluid and Whole Blood for Therapeutic Drug Monitoring"],"prefix":"10.1093","volume":"6","author":[{"given":"Nilo J C","family":"Duarte","sequence":"first","affiliation":[{"name":"Central Laboratory Division, Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"},{"name":"Laborat\u00f3rio de Investiga\u00e7\u00e3o M\u00e9dica (LIM 03), Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"L\u00e9onard V K","family":"Kupa","sequence":"additional","affiliation":[{"name":"Rheumatology Division Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Julio C R","family":"Ferreira-Filho","sequence":"additional","affiliation":[{"name":"Rheumatology Division Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicole","family":"Fontoura","sequence":"additional","affiliation":[{"name":"Rheumatology Division Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marc Y","family":"Chalom","sequence":"additional","affiliation":[{"name":"Central Laboratory Division, Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paschoalina","family":"Romano","sequence":"additional","affiliation":[{"name":"Central Laboratory Division, Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"},{"name":"Laborat\u00f3rio de Investiga\u00e7\u00e3o M\u00e9dica (LIM 03), Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"P\u00e9rsio A R","family":"Ebner","sequence":"additional","affiliation":[{"name":"Central Laboratory Division, Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"},{"name":"Laborat\u00f3rio de Investiga\u00e7\u00e3o M\u00e9dica (LIM 03), Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Clovis A A","family":"Silva","sequence":"additional","affiliation":[{"name":"Rheumatology Division Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Valdemir M","family":"Carvalho","sequence":"additional","affiliation":[{"name":"Grupo Fleury, Sao Paulo, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eloisa","family":"Bonf\u00e1","sequence":"additional","affiliation":[{"name":"Rheumatology Division Hospital das Cl\u00ednicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, 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