“…All three drugs are official in Indian pharmacopoeia (IP) [11] and British Pharmacopoeia (BP) [9] . The PCM, CPM and PH alone or in combination with other drugs are reported to be estimated by the spectrophotometric method [12] , [13] , [14] , [15] , derivative spectrophotometric method [16] , chemometric-assisted spectrophotometry [17] , HPLC [18] , [19] , thin layer chromatography (TLC) [20] , liquid chromatography–mass spectrometry (LC–MS) [21] , Fourier transform infrared spectroscopy (FT–IR) [22] , amperometric determination [23] , fluorimetry [24] , micellar electrokinetic chromatographic method [25] , electrophoresis [26] , liquid chromatography with two ultraviolet (UV) absorbance detectors [27] , and chemometric determination [28] .…”