NEW SPECTROPHOTOMETRIC METHODS FOR THE QUANTITATIVE ESTIMATION OF REFAXIMIN IN FORMULATIONS.

Three new spectrophotometric methods were proposed for the Quantative Estimation of Rifaximin. Method A(Ferri cyanide method) is oxidation of Rifaximin by excess of ferric salt in Ferricyanide and ferric chloride , Method B is diazotization of Para nitro Aniline (PNA) with sodium nitrate fallowed by coupling with drug in alkaline medium (PNA Method), in Method C (MBTH Method) MBTH was oxidized by the ferric chloride in acidic medium followed by its coupling with the drug. Linearity ranges and RSD will be 6-20ppm and 1.47 for Method A and 2-14 ppm and 0.45 for Method B and 5-30ppm and 0.904 for method C. All these method are Accurate, precise and very effective even at low concentrations and used for the quantitive estimation of Rifaximin in commercial formulations.