METHOD FOR PRODUCING DOXAZODIN MESYLATE IN A CRYSTAL MODIFICATION DESIGNATED AS FORM A AND INTERMEDIATE PRODUCT FOR PRODUCING THE SAME

摘要

Disclosed is a method for the production of doxazodin mesylate according to modification A, wherein doxazodin is dissolved with methanesulfonic acid in methanol or in a mixture of an aprotic polar organic solvent and methanol. Turbidity is optionally eliminated in the solution thus obtained. The resulting clear solution is stirred until no precipitation occurs and it is then separated and washed with methanol. The wet precipitate is then heated in ethanol and the resulting product is isolated after cooling.