“…Until recently, there were many studies about RPN including spectroscopic methods [6][7][8][9], liquid chromatographic (LC) methods [6,[10][11][12][13][14][15][16][17][18], high performance (HP) thin layer chromatographic (TLC) methods [9,19], LC methods combined with tandem mass spectrometry (MS/MS) [20] and with electrospray ionization-tandem mass spectrometry (ESI-MS/ MS) [21], chromatography with chemometric method [22], capillary zone electrophoretic (CZE) methods [23], and voltammetric methods [18,24]. The reported methods have many shortcomings such as potential loss of drugs in the reextraction procedure, need of lengthy, tedious, and time consuming plasma preparation and extraction process.…”