title: Capillary electrochromatography of caffeine and its metabolites in rat brain microdialysate.
abstract: A capillary electrochromatography (CEC) method has been developed for the separation of caffeine and its two metabolites 1-methylxanthine (1-MX) and 1,7-dimethylxanthine (1,7-DX). The stationary phase was 3-(1,8-naphthalimido) propyl-modified silyl silica gel (NAIP) and the best separations were achieved with 4.0 mM citrate buffer (pH 5.0) containing 80% methanol at an applied voltage of 25 kV. The compounds were completely separated in less than 3.5 min with good repeatability, which was approximately 3-times less than that in high-performance liquid chromatography (HPLC) with NAIP. The proposed method coupled with microdialysis was successfully applied to the monitoring of caffeine concentration in rat brain with detection limits of 1.11 microg/mL.
authors.affiliation: Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Kaname
authors.initials: K
authors.lastname: Ohyama
authors.affiliation: Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Wada
authors.affiliation: MRC Bioanalytical Science Group, School of Biological &Chemical Sciences, Birkbeck, University of London, London, UK.
authors.forename: Gwyn A
authors.initials: GA
authors.lastname: Lord
authors.affiliation: Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Ohba
authors.affiliation: Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Mihoko N
authors.initials: MN
authors.lastname: Nakashima
authors.affiliation: Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Nakashima
authors.affiliation: Department of Applied Physics and Chemistry, Fukui University of Technology, Fukui, Japan.
authors.forename: Shuzo
authors.initials: S
authors.lastname: Akiyama
authors.affiliation: MRC Bioanalytical Science Group, School of Biological &Chemical Sciences, Birkbeck, University of London, London, UK.
authors.forename: Chang Kee
authors.initials: CK
authors.lastname: Lim
authors.affiliation: Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Kuroda
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002021:Buffers; D002110:Caffeine / Q000302:isolation & purification* / Q000378:metabolism*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008297:Male; D000432:Methanol; D017551:Microdialysis; D009942:Organometallic Compounds; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results
chemical_list: C498079:3-(1,8-naphthalimido)propyl-modified silica gel; D002021:Buffers; D009942:Organometallic Compounds; D002110:Caffeine; D000432:Methanol
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