Analytical method development and validation of rifaximin and ornidazole in bulk and combined tablet dosage form as per ICH guidelines

A precise and accurate HPLC method was developed for the detection of ornidazole and rifaximin in bulk
and combination dosage form. Chromatography was done using acetonitrile and ammonium acetate
buffer as the mobile phase, at a 65:35 ratio, on a 250 x 4.6 mm, 5 µm hypersil C18 column. Based on the
features superimposed on it, a detection wavelength of 280 nm was selected for the study. According to
ICH criteria, the procedure was verified for rifaximin. Linearity was determined to be 100 to 300 g/ml for
ornidazole 125 to 375 g/ml for rifaximin. Ornidazole and rifaximin both had correlation coefficients of
0.9999. The formulation analysis findings and the label claim were in good accord the accuracy of the
approach was demonstrated by the percentage RSD, which was determined to be 0.15 per cent for
ornidazole and 0.23 per cent for rifaximin, respectively, recovery studies validated the method precision.
Ornidazole's percentage recovery was found to be between 100.54 per cent and 100.33 per cent and
rifaximin percentage recovery was found to be between 99.90 per cent and 100.34 per cent, demonstrating
the method accuracy. The findings of the validation parameters demonstrate the method adequacy for the
simultaneous estimate of the chosen medicines. The suggested RP-HPLC processes are accurate, precise,
robust, repeatable, and suitable for routine quality control analysis of rifaximin and ornidazole in bulk and
in its combination medicinal dosage form.