Normal-phase LC method for simultaneous analysis of pseudophedrine hydrochloride, dextromethorphan hydrobromide, chlorpheniramine maleate, and paracetamol in tablet formulations.

A simple, precise, and accurate method is developed and validated for the analysis of pseudophedrine hydrochloride, dextromethorphan hydrobromide, chlorpheniramine maleate, and paracetamol in tablet formulations. The method has shown adequate separation of the four ingredients from each other. Separation was achieved on a silica column (5 μm, 125 × 4.6 mm inner diameter) using a mobile phase consisting of methanol/ammonium dihydrogen phosphate buffer (90:10, v/v) at a flow rate of 1.0 ml/min and UV detection at 220 nm. This new method is validated in accordance with USP requirements for new methods for assay determination, which include accuracy, precision, selectivity, linearity and range, robustness and ruggedness. The current method demonstrates good linearity over the range of 0.15-0.45 mg/ml of pseudophedrine hydrochloride with r (2) of 0.996, and in the range of 0.075-0.225 mg/ml of dextromethorphan hydrobromide with r (2) of 0.992, and in the range of 0.01-0.03 mg/ml of chlorpheniramine maleate with r (2) of 0.994, and in the range of 0.25-0.75 mg/ml of paracetamol with r (2) of 0.991. The average recovery of the method is 99.7%, 98.6%, 98.1%, and 99.2% for pseudophedrine hydrochloride, dextromethorphan hydrobromide, chlorpheniramine maleate, and paracetamol, respectively. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing analytical operator has proven that the method is robust and rugged.