UPLC-MS/MS method for determination of bepotastine in human plasma

A sensitive and rapid method for quantitation of bepotastine in human plasma has been established using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). Valsartan was used as an internal standard. Bepotastine and internal standard in plasma sample were extracted using ethylacetate (liquid-liquid extraction). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile--5 mM ammonium formate (pH 3.5) (85:15, v/v). The reconstituted samples were injected into a phenyl column. Using MS/MS in the multiple reaction monitoring mode, bepotastine and valsartan were detected without severe interference from human plasma matrix. Bepotastine produced a protonated precursor ion ([M+H](+)) at m/z 389 and a corresponding product ion at m/z 167. And the internal standard produced a protonated precursor ion ([M+H](+)) at m/z 436 and a corresponding product ion at m/z 291. Detection of bepotastine in human plasma by the UPLC-ESI-MS/MS method was accurate and precise with a quantitation limit of 0.2 ng/mL. The validation, reproducibility, stability and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of bepotastine in human plasma.