title: Simultaneous determination of theophylline and dyphylline by micellar electrokinetic chromatography and application in drug formulations.
abstract: A simple micellar electrokinetic chromatography is described for well resolution of theophylline, dyphylline and caffeine. The separation was performed at 25 degrees C using a background electrolyte consisting of 10mM borate buffer at pH 9 and 40 mM sodium dodecyl sulfate (SDS) as running buffer. Under this condition, good separation with high efficiency and short analyses time required is achieved. Several parameters affecting the separation of the drugs were studied, including the pH and concentrations of the borate buffer and sodium dodecyl sulfate. Using caffeine as an internal standard (I.S.), the linear range of the method for the determination of theophylline and dyphylline was over 0.03-1 micromol ml(-1); the detection limit (signal-to-noise ratio 3; injection 0.3 psi, 3s) was 0.01 and 0.02 micromol ml(-1), respectively.
authors.affiliation: Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
authors.forename: Wei-Shan
authors.initials: WS
authors.lastname: Huang
authors.forename: Shun-Jin
authors.initials: SJ
authors.lastname: Lin
authors.forename: Hsin Lung
authors.initials: HL
authors.lastname: Wu
authors.forename: Su-Hwei
authors.initials: SH
authors.lastname: Chen
mesh_terms: D002138:Calibration; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D004400:Dyphylline / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D012015:Reference Standards; D015203:Reproducibility of Results; D013806:Theophylline / Q000032:analysis*
chemical_list: D004400:Dyphylline; D013806:Theophylline