Determination of ephedrine, pseudoephedrine, sinapine thiocyanate, tetrahydropalmatine and amygdalin by HPLC-MS/MS after oral administration of extracts of Majie cataplasm in rabbits plasma: Application to a pharmacokinetic study

Abstract BackgroundThis study aimed to develop HPLC-MS/MS method for quantification of ephedrine, pseudoephedrine, sinapine thiocyanate, tetrahydropalmatine and amygdalin of extracts of Majie cataplasm after oral administration in rabbits plasma and describe the pharmacokinetics of this five components.MethodsThe qualitative detection of the five compounds was accomplished by two methods. One method for the simultaneous determination of ephedrine, pseudoephedrine, sinapine thiocyanate and tetrahydropalmatine was developed and validated for the first time, while the other method was for amygdalin. Chromatographic separations were achieved on a C18 column using gradient elution with the mobile phase consisting of acetonitrile and water (containing 0.1% formic acid and 5mM ammonium formate) for ephedrine, pseudoephedrine, sinapine thiocyanate and tetrahydropalmatine, while acetonitrile and water for amygdalin, at a flow rate of 0.4 mL/min. The initial gradient was extended in order to isolate ephedrine and pseudoephedrine better. The detection was performed in multiple-reaction monitoring (MRM) mode using electrospray ionization (ESI).ResultsAll calibration curves showed good linearity (r2＞0.996) within the test ranges. The lower limit of quantification was 0.01 ng/mL for all five analytes. Reproducibility for five analytes ranged from 0.79 to 2.3% (Ephedrine), 0.51 to 3.4% (pseudoephedrine), 2.8 to 5.0% (Sinapine thiocyanate), 2.6 to 6.3% (Tetrahydropalmatine) and 1.1—2.5% (amygdalin) respectively. The extraction recoveries were within the acceptable range.ConclusionThe two methods were successfully applied to pharmacokinetic study of rabbits after oral administration. The two methods has several advantages including good chromatographic resolution, specific and reproducibility and superior minimum detection limit. The results provided a basis for further study on the bioactivity of Majie cataplasm.