SIMULTANEOUS DETERMINATION OF LEVODROPROPIZINE, METHYLPARABEN, AND PROPYLPARABEN IN ORAL CO-FORMULATED SYRUP BY RP-HPLC METHOD

Abstract

A selective, rapid, isocratic RP-HPLC method has been developed and validated for the simultaneous determination of the cough suppressant drug levodropropizine and its two co-formulated preservatives methylparaben and propylparaben in Levopront (R) syrups. The chromatographic separation was achieved on Inertsil (R) C18, (250 mm x 4.6mm, 5 mu m) column using a mixture of (acetonitrile: 0.1 % triethylamine in water, pH 3.0) 50: 50: (v/v), as a mobile phase with a flow rate of 1.0 ml/min, at 30 degrees C column temperature and detector wavelength of 240 nm. All peaks were symmetrical and well resolved in a short run time. Method validation demonstrated to be selective, accurate and precise with good linearity over the concentration range of (7.5-60 mu g/ml), (1.625-13 mu g/ml), and (0.25-2 mu g/ml) with limits of detection and quantification of 0.502 and 1.520 mu g/ml, 0.071 and 0.215 mu g/ml, and 0.040 and 0.122 mu g/ml for Levodropropizine, Methylparaben, and Propylparaben, respectively. Robustness against small modifications of column temperature, flow rate and pH of the mobile phase was ascertained. The developed method was successfully applied for the separation and quantification of Levodropropizine in presence of its two co-formulated preservatives in drug substances and in Levopront (R) oral pharmaceutical formulation; therefore it's highly suitable for routine analysis in QC labs.