Abstract

A low cost, accurate, rapid and sensitive capillary zone electrophoresis (CZE) quantitative method, using thiamine
hydrochloride as internal standard (IS), was developed for the simultaneous analysis of ephedrine and
pseudoephedrine in mice plasma. Analytes were extracted from plasma samples by
n-hexane/dichloromethane/isopropanol (2:1:0.1, v/v/v) after alkalization, and stripped with 1.5% hydrochloric acid
solution. Separation was performed by CZE using 50mM borax-20mM threonine (pH 9.27) as running buffer, with
voltage of +10 kV applied and UV detection wavelength at 210 nm. The total running time was within 10 min.
Calibration curves for plasma samples were linear over the concentration range of 0.075-5.0 ?g/mL for ephedrine
and 0.0375-2.5 ?g/mL for pseudoephedrine. The method had a limit of quantitation of 17.80 ng/mL for ephedrine
and 22.00 ng/mL for pseudoephedrine,respectively. The method was reliable and feasible for the evaluation of
pharmacokinetic profiles of drug products containing ephedrine and pseudoephedrine.

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