title: Determination of two COX-2 inhibitors in serum and synovial fluid of patients with inflammatory arthritis by ultra performance liquid chromatography-inductively coupled plasma mass spectroscopy and quadrupole time-of-flight mass spectrometry.
abstract: The determination of two sulphur-containing drugs, the COX-2 inhibitors celecoxib and etoricoxib, in the serum and synovial fluid of inflammatory arthritis patients, is described using a sensitive ultra performance liquid chromatography-inductively coupled plasma mass spectroscopy (UPLC/ICPMS) method. Confirmation of the identity of the analytes in the samples was also performed by electrospray quadruple time-of-flight mass spectrometry in positive electrospray ionisation mode. The two COX-2 inhibitors were extracted from serum and synovial fluid following dilution with acetate buffer (pH 5) and liquid-liquid extraction (LLE) into ethyl acetate. Extracted samples were then analysed using UPLC/ICPMS with sulphur-specific detection. The limit of detection by UPLC/ICPMS was 0.45 ng/ml of sulphur in both serum and synovial fluid. The UPLC/ICPMS method was applied to the analysis of samples from patients receiving either 200 mg/day of celecoxib (2x 100 mg), 90 mg/day etoricoxib or placebo. The range of concentrations detected in the samples for the two drugs was from 0.3 to 3.3 microg/ml.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University, 54124 Thessaloniki, Greece. gkikae@chem.auth.gr
authors.forename: Helen G
authors.initials: HG
authors.lastname: Gika
authors.forename: Athina
authors.initials: A
authors.lastname: Theodoridou
authors.forename: Filippos
authors.initials: F
authors.lastname: Michopoulos
authors.forename: Georgios
authors.initials: G
authors.lastname: Theodoridis
authors.forename: Eudoxia
authors.initials: E
authors.lastname: Diza
authors.forename: Lucas
authors.initials: L
authors.lastname: Settas
authors.forename: Paul
authors.initials: P
authors.lastname: Nikolaidis
authors.forename: Christopher
authors.initials: C
authors.lastname: Smith
authors.forename: Ian D
authors.initials: ID
authors.lastname: Wilson
mesh_terms: D000328:Adult; D000368:Aged; D001168:Arthritis / Q000097:blood / Q000378:metabolism*; D000068579:Celecoxib; D002851:Chromatography, High Pressure Liquid; D052246:Cyclooxygenase 2 Inhibitors / Q000032:analysis* / Q000097:blood; D000077613:Etoricoxib; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D011720:Pyrazoles / Q000032:analysis* / Q000097:blood; D011725:Pyridines / Q000032:analysis* / Q000097:blood; D012015:Reference Standards; D021241:Spectrometry, Mass, Electrospray Ionization; D013449:Sulfonamides / Q000032:analysis* / Q000097:blood; D013450:Sulfones / Q000032:analysis* / Q000097:blood; D013582:Synovial Fluid / Q000737:chemistry* / Q000378:metabolism*; D055815:Young Adult
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D011720:Pyrazoles; D011725:Pyridines; D013449:Sulfonamides; D013450:Sulfones; D000068579:Celecoxib; D000077613:Etoricoxib