SIMULTANEOUS QUANTIFICATION OF RISPERIDONE AND ESCITALOPRAM IN HUMAN PLASMA BY LC-MS/MS: APPLICATION TO A PHARMACOKINETIC STUDY

Pallavi Alegete, Prasad Kancherla, Saeed S. Albaseer, and Sathyanarayana Boodida*

A solid phase extraction method was developed for the simultaneous quantification of risperidone and escitalopram in human plasma by a suitable ultra-performance liquid chromatographic / tandem mass spectrometric assay (LCMS/ MS) .Resperidone-D4 was used as an internal standard. The method involves simple isocratic chromatographic conditions at a flow rate of 0.400 mL min-1. Samples were separated on X-terra RP8 column (50 mm × 4.6, 5μm) in a shorter run time of only 2.0 min using a mobile phase mixture of 95:5 v/v (acetonitrile : ammonium acetate) buffer 5mM, pH 5.0±0.05). Calibration plots were linear (r2 > 0.99) over the concentration range of 0.050 to 26 ng mL-1 for risperidone and 0.100 to 51 ng mL-1 for escitalopram. The overall recoveries for risperidone and escitalopram were 76.88% and 81.14%, respectively. Precision was 2.9%, 5.07% (intra-day) and 4.13%, 6.43% (inter-day) for risperidone and escitalopram, respectively. The validated method was successfully applied to a pharmacokinetic study of human plasma.