| 摘要 |
<p>The present invention discloses a process for the obtainment of Rifaximin in the amorphous form thereof through managing the original basic pH of the reaction between Rifamycin O and 2-amino-4-methylpyridine and the purification thereof with ethanol. It is thus demonstrated that Rifaximin obtained in this manner does not depend on moisture content to determine the crystalline form thereof, but that it is a function of pH. Furthermore, conversion of the a, ß or ? crystalline form to the amorphous form is realized through changing the pH from acidic to basic, confirming that the form of the crystal does not depend on moisture content.</p> |
