A Validated Reverse Phase LC Method for the Simultaneous Estimation of Fexofenadine HCl and Pseudoephedrine HCl in Pharmaceutical Dosage form Using a Monolithic Silica Column

Abstract

A simple, rapid, accurate, precise and sensitive isocratic reverse phase high performance liquid chromatographic method (RP-LC) has been developed for the simultaneous estimation of fexofenadine HCl (FEX) and pseudoephedrine HCl (PSE) in pharmaceutical dosage forms from their combination formulation. The proposed method utilized Chromolith ® Performance, RP-18e, 100 mm × 4.6 mm column and the separation was achieved with mobile phase consisted of phosphate buffer pH 4.5:acetonitrile:methanol (65:25:10 v/v), delivered at a flow rate of 2.4 mL/min and wavelength of detection at 258 nm. Losartan was chosen as the internal standard which elution is between the two tested active ingredients to guarantee a high level of quantitative performance. The method has shown adequate separation using losartan with good resolution to both of the active ingredients, in which contest the retention time of pseudoephedrine HCl, losartan and Fexofenadine HCl were 0.7, 2.1 and 2.7 min, respectively. The described method was linear over the range of 0.8-100 μg mL^-1 (r = 0.9995) for fexofenadine HCl and 2.0-200 μg mL^-1 (r = 0.9999) for pseudoephedrine HCl. Intra- and inter-day % RSD (n = 6) was £ 1.0 %. The percentage recovery of the two drugs from their tablet formulation were 99.5 ± 0.3 (FEX) and 99.6 ± 0.4 (PSE). The developed method was validated according to ICH guidelines. The method can be used for rapid and accurate quantitative determination of these drugs in combined dosage forms.