Orthogonal array design for optimization of hollow-fiber-based liquid-phase microextraction combined with high-performance liquid chromatography for study of the pharmacokinetics of magnoflorine in rat plasma.

In this work, a new sample-preparation method based on hollow-fiber liquid-phase microextraction (HF-LPME) was developed for analysis of magnoflorine in rat plasma. Analysis was accomplished by reversed-phase high-performance liquid chromatography (HPLC), with ultraviolet detection by use of a photodiode-array detector. An orthogonal array design (OAD) was found to be effective for optimization of major conditions which may affect the efficiency of HF-LPME. Under the optimized conditions (pH of donor and acceptor phases 12 and 2.0, respectively; extraction time 20 min; stirring speed 800 rpm; and addition of 10 % (w/v) salt), the preconcentration factor for magnoflorine was 355. Calibration curves with reasonable linearity (r(2)≥0.9994) were obtained in the range 10-1000 ng mL(-1). Intra-day and inter-day precision (RSD) were <5.5 % and the limit of detection (LOD) for the analyte was 3.0 ng mL(-1) (S/N=3). The validated method was successfully used for pharmacokinetic studies of magnoflorine in rat plasma after intravenous administration.