Quantification of pentoxyverine citrate in human plasma by LC-ESI/MS method and its application

A rapid and sensitive liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI/ MS) method for quantification of pentoxyverine citrate in human plasma has been developed and applied for the bioequivalence and pharmacokinetics study.  After extracted from plasma samples with ethyl acetate, analysis  was performed in selected ion monitoring (SIM) mode with a positive electrospray ionization (ESI) interface with a mobile phase consisted of methanol and water (0.4% glacial acetic acid and 4 mmol·L⁻¹ ammonium   acetate, 43∶57, v/v).  The linear concentration range of the calibration curves was 1.0−160.0 ng·mL⁻¹ for  pentoxyverine citrate, inter- and intra-precision (RSD) was less than 12.5%, accuracy (RE) was in ±13.5% and absolute recovery was more than 80%.  The method was proved simple, rapid, sensitive, specific and suitable for pharmacokinetic and bioequivalence study of Yufenweilin capsule containing pentoxyverine citrate.