title: Analysis of fluoxetine and norfluoxetine in human plasma by liquid-phase microextraction and injection port derivatization GC-MS.
abstract: A two-phase liquid phase microextraction using a hollow fiber combined with injection port derivatization and gas chromatographic analysis was developed for extracting and detecting fluoxetine (FLU) and norfluoxetine (NOR) in human plasma. Simultaneous extraction in a multiple tube shaker was used and, afterward, the organic phase was simply injected together with the derivatizing agent n-methyl-bis(trifluoroacetamide) (MBTFA). Factors influencing injection port derivatization, and several extraction parameters were optimized. Under optimal conditions the proposed method provided linearity between 10 and 500ngmL(-1) (R(2)=0.9973) for FLU, and between 15 and 500ngmL(-1) (R(2)=0.9972) for NOR. Intra-assay precision (RSD) between 4.8 and 13.1% and inter-assay between 5.4 and 14.2% were obtained, with detection and quantification limits of 3 and 10ngmL(-1), and of 5 and 15ngmL(-1) for FLU and NOR, respectively, using selected ion monitoring mode. Selectivity, short term stability and extraction efficiency were also evaluated. This method was simple, cheap, and environmentally friendly, yielding significant reduction of solvents and derivatizing agent consumption. The method was successfully applied to the analysis of samples from 5 patients under fluoxetine treatment.
authors.affiliation: Federal University of Alfenas, Faculty of Pharmaceutical Sciences, R. Gabriel Monteiro da Silva 714, 37130-000, Alfenas, MG, Brazil.
authors.forename: Antônio Felipe Felicioni
authors.initials: AF
authors.lastname: Oliveira
authors.forename: Eduardo Costa
authors.initials: EC
authors.lastname: de Figueiredo
authors.forename: Alvaro José
authors.initials: AJ
authors.lastname: Dos Santos-Neto
mesh_terms: D016903:Drug Monitoring / Q000379:methods*; D005473:Fluoxetine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D007700:Kinetics; D016014:Linear Models; D059627:Liquid Phase Microextraction / Q000379:methods*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D013997:Time Factors
chemical_list: D005473:Fluoxetine; D017367:Selective Serotonin Reuptake Inhibitors; C036139:norfluoxetine