Rifaximin

Abstract

Amorphous rifaximin, methods of making it, and pharmaceutical compositions containing it. Also described are methods of converting amorphous rifaximin to crystalline rifaximin and vice versa.

1 .- 22 . (canceled) 
     
     
         23 . A pharmaceutical composition comprising amorphous rifaximin, silicon dioxide, disodium edetate, hydroxypropyl methyl cellulose, microcrystalline cellulose, sodium starch glycolate, and glycerol palmitostearate. 
     
     
         24 . The pharmaceutical composition of  claim 23 , wherein the amorphous rifaximin is characterized by the XRPD pattern shown in  FIG. 1 . 
     
     
         25 . The pharmaceutical composition of  claim 23 , wherein the pharmaceutical composition is in tablet form. 
     
     
         26 . A method of treating a bowel related disorder in a patient in need thereof, the method comprising administering a therapeutically effective amount of the pharmaceutical composition of  claim 23  to the patient. 
     
     
         27 . The method of  claim 26 , wherein the bowel related disorder is selected from the group consisting of irritable bowel syndrome, traveler's diarrhea, Crohn's disease, chronic pancreatitis, pancreatic insufficiency, and colitis.