A highly sensitive HPLC-MS/MS method for the determination of difenidol in human plasma

A rapid, simple, and highly sensitive HPLC-MS/MS method for the determination of difenidol concentration in human plasma. This method involves pretreating plasma samples with acetonitrile and using difenidol-d10 as an isotopic internal standard. Analytes are separated on a C18 column and detected by electrospray ionization. The method exhibits excellent linearity, precision, accuracy, and sensitivity, with a wide linear range of 0.200–200 ng/mL and a lower limit of quantification of 0.200 ng/mL. Due to its short chromatographic running time, small injection volume, and high sensitivity, this method provides a useful supplement for studying the bioequivalence of difenidol in human plasma. We believe that this method has the potential to be applied in clinical research and treatment monitoring, contributing to the ongoing efforts of the scientific community.