RP-HPLC DETERMINATION OF RIFAXIMIN IN BULK DRUG AND PHARMACEUTICAL FORMULATIONS *K. Nageswara Rao, S. Ganapaty and A. Lakshmana Rao A simple, rapid, sensitive, accurate and precise HPLC method has been developed and validated for the estimation of Rifaximin in bulk and its pharmaceutical dosage forms. The method was carried out using Chromosil Symmetry C18 (150 x 4.6 mm I.D., 5 m particle size) column and mobile phase comprised of phosphate buffer pH 4.0 and acetonitrile in proportion of ratio 40:60 v/v and degassed in ultrasonic water bath. The flow rate was 1.0 mL/min and the detection wavelength was at 292 nm. The linearity was observed in the range of 10-60 µg/mL with a correlation coefficient of 0.999. The retention time of Rifaximin was 2.963 min. The method was validated as per the ICH guidelines for its linearity, precision, accuracy, specificity, limit of detection, limit of quantitation and by performing recovery studies. The percentage recovery of the drug Rifaximin was 100.6% to 101.4% from the tablet formulation. The proposed method is suitable for the routine quality control analysis for the estimation of Rifaximin in bulk and pharmaceutical dosage form. <br /> International Journal Of Pharmacy 2249-1848 2013-01-01 1 7-13 Copyright (c) Pharma Scholars. All rights reserved 2013