DEVELOPMENT AND VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR ESTIMATION OF RIFAXIMIN IN BULK AND FORMULATION.

A reverse-phase high-performance liquid chromatographic method was developed and validated as per ICH guidelines for the determination of Rifaximin in bulk and formulation. The samples were analyzed by high-performance liquid chromatography (HPLC). Chromatographic separation was achieved on an inertsil C18 (250 x 4.6 mm, packed with 5µ) column using an aqueous sodium acetate buffer:Acetonitrile (60:40 v/v pH adjusted to 5.0 by using NaOH) with flow rate 1.0ml/min at ambient temperature and the retention time was about 3.489 minutes. UV detection was found at 293nm. Linearity was observed over the concentration range of 20-80 µg/ml (R2 = 0.9997). The LOD and LOQ were found to be 0.7129?g/ml and 2.160µg/ml respectively. Rifaximin was subjected to stress conditions of degradation in aqueous solutions including acidic, alkaline, oxidation and thermal degradation. The forced degradation studies were performed by using 0.1 M HCl, 0.1 M NaOH, 30% H2O2 and thermal at 1000C. Rifaximin is more sensitive towards acidic conditions in comparison to oxidation and alkaline degradation. The method was validated as per ICH guidelines. The proposed method is simple, specific, selective, precise, linear, cost effective and rapid and is applicable to routine analysis of Rifaximin in bulk and pharmaceutical dosage forms.