PROCESS FOR THE PREPARATION OF THE POLYMORPH A OF DOXAZOSIN MESYLATE

摘要

The invention discloses a process for the preparation of the polymorph A of doxazosin mesylate, consisting essentially of reacting doxazosin base with methanesulfonic acid in a mixture of solvents containing an alcohol and a chlorinated solvent, subsequently removing the chlorinated solvent by distillation and precipitating the desired product in an alcohol, after heating the suspension formed to the reflux temperature of the solvent.