Process for the preparation of amorphous form of torsemide

#The present invention relates to a simple and efficient process for the preparation of amorphous form of torsemide.

#Chemically, torsemide is 1-isopropyl-3-[(4-m-toludino-3-pyridyl)-sulphonyl]-urea and has the structural formula I.

#Torsemide is used for the treatment of hypertension and edema associated with congestive heart failure, renal disease or hepatic disease. Torsemide is a loop diuretic whose primary site of action is the ascending limb of the loop of Henle. It has a sustained duration of action unlike standard loop diuretics. It is also used in the treatment of hypertension.

#The present invention is further illustrated by the following example, which is not intended to limit the scope of this invention in any way.

#Preparation of Amorphous Form of Torsemide

#Crystalline torsemide (3.0 g) was dissolved in acetone (540 ml) at 45–50° C. The clear solution thus obtained was subjected to spray drying in a Mini Spray Dryer (Model Buchi—190) with an inlet temperature of 75–77° C. and an outlet temperature of 52–58° C. The fine powder of torsemide in an amorphous form was collected. It was further dried under vacuum at 30–35° C. to yield 1.8 g of torsemide of amorphous form. X-ray powder diffraction pattern showed a plain halo which demonstrates the amorphous nature of the product (FIG. 1).