Method for the preparation of crystal forms of torsemide in a pure state

摘要

A method for the preparation of crystal form 1 of polymorphous crystalline torsemide, wherein torsemide is dissolved in an ethanol-water mixture with heating, after which the torsemide is subsequently cooled and dried once crystal separation has been performed. Drying takes place in a blade drier, for example, with the crystals being subjected to mechanical stress, wherein the crystals of crystalline form 2 are transformed into crystalline form 1.