An isocratic reversed-phase high-performance liquid chromatographic method was developed and validated for the determination of Rifaximin. Chromatographic separation was achieved on a C18 column using an aqueous tetra butyl ammonium hydrogen sulphate (10 mM) (pH 3.37): acetonitrile (40:60, v/v), with flow rate 1.2 mL/min (UV detection at 441 nm). Linearity was observed in the concentration range of
0.1–200 μg/mL (R2 = 0.9999). The limit of quantitation was found to be 0.0794 μg/mL and the limit of detection was found to be 0.0241 μg/mL. Rifaximin was subjected to stress conditions of degradation in aqueous solutions including acidic, alkaline, oxidation, photolysis and thermal degradation. The forced degradation studies were performed by using HCl, NaOH, H2O2, thermal and UV radiation. Rifaximin is more sensitive towards acidic conditions in comparison to oxidation and very much resistant towards alkaline, thermal and photolytic degradations. The method was validated as per ICH guidelines. The method is simple, specific, precise, robust and accurate for the determination of Rifaximin in pharmaceutical formulations.
RP-HPLC, Rifaximin, Stability-indicating, Validation, ICH