title: Enantioselective HPLC determination of E-6087, a new COX-2 inhibitor, in human plasma: Validation and pharmacokinetic application.
abstract: E-6087 is a nonsteroidal anti-inflammatory compound that selectively inhibits cyclooxygenase-2. Because E-6087 has a chiral center, this compound is a racemic mixture of two stereoisomers, (+)-(R)-E-6087 (E-6231) and (-)-(S)-E-6087 (E-6232). A normal-phase liquid-chromatographic method for the enantioselective determination of E-6087 in human plasma was developed and validated. The samples were extracted using solid-phase extraction cartridges containing C(18) sorbent, and the extracts were redissolved in absolute ethanol and injected into the chromatographic system. The enantiomeric separation was achieved on a chiral stationary-phase column of derivatized amylose, and the enantiomers were quantified by fluorescence detection. The method was validated for drug concentrations ranging from 5 to 400 ng/ml for both enantiomers. No peaks interfering with the quantification of enantiomers were observed. The limit of quantification was 5 ng/ml, with precision expressed as a coefficient of variation lower than 10.6% and accuracy expressed as relative error lower than 12.2%. The utility of this method was demonstrated by analysis of plasma samples from healthy volunteers given an oral dose of rac-E-6087. Peak plasma levels of E-6231 were higher than levels obtained for E-6232. Results were consistent with those obtained with a conventional reversed-phase method used for determination of the racemic compound.
authors.affiliation: Pharmacokinetics and Drug Metabolism Department, Laboratorios Dr. Esteve, S.A., Barcelona, Spain.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Salgado
authors.forename: Gregorio
authors.initials: G
authors.lastname: Encina
authors.forename: Ramón
authors.initials: R
authors.lastname: Farran
authors.forename: Santiago
authors.initials: S
authors.lastname: Puig
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez
mesh_terms: D002138:Calibration; D002845:Chromatography; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002986:Clinical Trials as Topic; D051546:Cyclooxygenase 2; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D008565:Membrane Proteins; D008956:Models, Chemical; D010949:Plasma / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases; D011720:Pyrazoles / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics; D013449:Sulfonamides / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics; D013997:Time Factors; D000096926:Benzenesulfonamides
chemical_list: D051546:Cyclooxygenase 2; D007527:Isoenzymes; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases; D011720:Pyrazoles; D013449:Sulfonamides; C496540:PTGS2 protein, human; C427706:enflicoxib; D000096926:Benzenesulfonamides