H-point standard addition method for simultaneous determination of phenylephrine hydrochloride, chlorpheniramine maleate, and paracetamol as a ternary mixture in pharmaceutical formulations

The simultaneous analysis of a ternary mixture containing paracetamol (PAR), phenylephrine hydrochloride (PHE), and chlorpheniramine maleate (CPM) was conducted without prior separation and using an advanced spectrophotometric method. The H-point standard addition and absorbance correction methods were selected to determine the compounds, which are highly overlapped spectra in pharmaceutical formulations. The method is based on the use of three different wavelengths of 296, 272, and 227 nm for the ternary mixture. The concentration of PAR was calculated directly at 296 nm because no interferences existed. Absorbance correction method was used to remove the role of PAR at 272 and 227 nm. The concentrations of the PHE and CPM compounds in the mixture were determined by using the H-point standard addition method. The results showed that simultaneous determination of PAR, PHE, and CPM could be conducted within the range of 1-33 mu g/mL, 1-23 mu g/mL, and 1-36 mu g/mL, respectively. The relative standard deviations for the simultaneous determination of PHE, CPM, and PAR were 0.617, 2.76, and 1.71, respectively. The proposed method was implemented successfully for the simultaneous determination of PAR, PHE, and CPM in pharmaceutical formulations.