Introduction: An effective high performance liquid chromatography-tandem mass spectrophotometric
(LCMS/MS) simultaneous quantitation of Escitalopram (ESC) and Etizolam (ETZ) in spiked
human plasma method was developed. Analytes extraction from plasma was performed by Liquid-liquid
extraction (LLE) technique.
Materials and Methods: Separation was performed on a Waters symmetry shield, C18 (4.6mm id x 50
mm) analytical column using acetonitrile: 1% formic acid (80:20) v/v with a flow rate of 600μl/min. The
MS/MS analysis was performed by multiple reaction monitoring (MRM) to obtain the product ion m/z
325.15 →108.99 for ESC, m/z 343.2 → 138.1 for ETZ and m/z 411.40 →191.30 for internal standard
(Risperidone). The obtained calibration curve was linear over the range of 3→2000 ng/ml for both the
analytes. Intra and inerday accuracy (% nominal 98 → 102%), precision (% CV ≤4.5%) was excellent. Matrix
effect (matrix factor 1.066 for ESC and 1.057 for ETZ), selectivity (% interference = 0) with acceptable
extraction recovery (92.75%→98.80%) and stability (% nominal 98.40→101.4%) of different types were
Conclusion: The proposed method was successfully applied for the pharmacokinetic study of marketed
formulation in rabbit blood samples in single oral human equivalents dose. The developed method has further
diversified during clinical and preclinical trials in human and other experimental animals.