title: Solid-phase extraction of methadone enantiomers and benzodiazepines in biological fluids by two polymeric cartridges for liquid chromatographic analysis.
abstract: The aim of this work was to present the advantages of two polymeric cartridges (Oasis HLB from Waters and Abselut Nexus from Varian) for the solid-phase extraction of methadone enantiomers and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and of some benzodiazepines (diazepam, flunitrazepam, nitrazepam, oxazepam) in serum and urine in comparison with classical C18-bonded-silica cartridges or liquid extraction. After addition of serum or urine samples, these two cartridges were washed with a water-methanol mixture (95:5, v/v) and eluted with diethylether. After rapid evaporation, the residue was regenerated with mobile phase and injected either in a chiral column (Cyclobond I-2000 RSP) for methadone enantiomers and its metabolite or in a reversed-phase column (Symmetry Shield RP8) for benzodiazepines. The results showed that the chromatograms of blank serum and urine were cleaner than those obtained from classical solid-phase extraction or liquid extraction. The recoveries from these two polymeric cartridges were higher (95-102%) than those obtained by the two previous classical methods and the total time for extraction and solvent evaporation was also shorter (about 6-7 min). For methadone and benzodiazepine extraction, the use of acidic or alkaline buffer was not necessary.
authors.affiliation: Division of Analytical Chemistry, China Pharmaceutical University, Nanjing 210009, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: He
authors.forename: Cheng
authors.initials: C
authors.lastname: Sun
authors.forename: Xiao-Rong
authors.initials: XR
authors.lastname: Wang
authors.forename: Chuong
authors.initials: C
authors.lastname: Pham-Huy
authors.forename: Nassima
authors.initials: N
authors.lastname: Chikhi-Chorfi
authors.forename: Hervé
authors.initials: H
authors.lastname: Galons
authors.forename: Marc
authors.initials: M
authors.lastname: Thevenin
authors.forename: Jean-Roger
authors.initials: JR
authors.lastname: Claude
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Warnet
mesh_terms: D000818:Animals; D001569:Benzodiazepines / Q000032:analysis* / Q000097:blood / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D008691:Methadone / Q000032:analysis* / Q000097:blood / Q000652:urine; D011108:Polymers / Q000737:chemistry*; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013237:Stereoisomerism
chemical_list: D011108:Polymers; D001569:Benzodiazepines; D008691:Methadone