Patent ID: 9403844
Filing Date: 2016-08-02
CPC Classification: A61K,A61P,C07D

Claim Text:
1. A process for manufacturing amorphous rifaximin comprising: a) reacting Rifamycin S with 2-amino-4-picoline in the presence of a suitable solvent b) adding iodine dissolved in suitable solvent to the above reaction mass followed by a reducing agent c) adjusting the pH of the reaction mass between 1.5-2.5 under stirring d) extracting with water immiscible organic solvent and concentrating the organic layer to form a residue e) stripping the residue obtained in step d) with a water immiscible solvent or mixture of water immiscible solvents to residue f) stirring the residue obtained in step e) with a water immiscible solvent or mixtures thereof to get a solid g) filtering the solid and washing the same solvent/s and h) drying the solid at a temperature below 40° C.