title: Liquid chromatography-tandem mass spectrometry method of loxoprofen in human plasma.
abstract: A rapid, sensitive and selective liquid chromatography-electrospray ionization mass spectrometric method for the determination of loxoprofen in human plasma was developed. Loxoprofen and ketoprofen (internal standard) were extracted from 20 microL of human plasma sample using ethyl acetate at acidic pH and analyzed on an Atlantis dC(18) column with the mobile phase of methanol:water (75:25, v/v). The analytes were quantified in the selected reaction monitoring mode. The standard curve was linear over the concentration range of 0.1-20 microg/mL with a lower limit of quantification of 0.1 microg/mL. The coefficient of variation and relative error for intra- and inter-assay at four quality control levels were 2.8-5.2 and 4.8-7.0%, respectively. The recoveries of loxoprofen and ketoprofen were 69.7 and 67.6%, respectively. The matrix effects for loxoprofen and ketoprofen were practically absent. This method was successfully applied to the pharmacokinetic study of loxoprofen in humans.
authors.affiliation: Drug Metabolism and Bioanalysis Laboratory, College of Pharmacy, Wonkwang University, Iksan 570-749, Korea.
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Lee
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Ji
authors.forename: Dong Hwan
authors.initials: DH
authors.lastname: Sohn
authors.forename: Se-Mi
authors.initials: SM
authors.lastname: Kim
authors.forename: Yong Bok
authors.initials: YB
authors.lastname: Lee
authors.forename: Hye Suk
authors.initials: HS
authors.lastname: Lee
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D006801:Humans; D007660:Ketoprofen / Q000097:blood / Q000737:chemistry; D016014:Linear Models; D008297:Male; D010666:Phenylpropionates / Q000097:blood* / Q000737:chemistry / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010666:Phenylpropionates; C040656:loxoprofen; D007660:Ketoprofen