RP-HPLC-PDA method for the simultaneous determination of Phenylepherine, Chlorpheneramine, Paracetamol and Dextromethorphan in bulk and marketed formulation

Objective: a new method has been developed for simultaneous estimation of phenylephrine, chlorpheneramine, paracetamol and dextromethorphan in bulk and marketed formulations. Method: Chromatography was performed using C8 column of dimension 250*4.6mm and particle size 5µ. the best results were obtained by phosphate buffer (20 Mm) pH 6.6 adjusted with diluted orthophosphoric acid and Acetonitrile(70:30) taken in Gradient Programme at flow rate of 1ml/m with detection at 225 nm. Retention time was less than 6mins for all the four drugs. According to ICH guidelines the method was proven to be linear, precise and accurate. Results: The linearity ranges from 0.5-487.5 µg/ml. LOQ was found to be 0.02,0.01,3.92 and 0.06. The sample solution injected after 24 hr did not show any appreciable change. Recovery was found to be 100.38-100.53. Conclusion: The developed method was simple, specific and sensitive as the excipients have no interference in the determination of main components. The proposed method can be used for routine analysis of phenylephrine, chlorpheneramine, paracetamol and dextromethorphan in combined dosage form which are present in variable concentrations.