Process for manufacturing rosuvastatin potassium and crystalline and amorphous forms thereof

Preparation of Amorphous Form of Rosuvastatin Potassium

[0047]In a 2 l four neck reaction flask equipped with a mechanical stirrer and temperature as well as pH monitoring facility, 625 ml of Methanol is added. To this reaction vessel 25.0 g Rosuvastatin protected diol of Formula—(IIa) is added under stirring. A solution thus obtained is cooled to 5-10° C., then the mixture of hydrochloric acid (7.5 ml) and water (52.5 ml) is added slowly within 20 minutes time. After complete addition, solution in the reaction flask is stirred it at 5-10° C. for 15 minutes. The resultant solution is warmed to 30-35° C. and stir for 45 minutes.

[0048]Reaction is monitored at this stage by Thin Layer Chromatography.

[0049]Again the stirred solution in the reaction vessel is cooled to 5-10° C. then slowly the solution of potassium hydroxide is added, which is made by dissolving 12.2 g of potassium in 122 ml of water at 5-10° C. The saponification is continued for 15 minutes under vigorous stirring at the...

Preparation of Crystalline Form of Rosuvastatin Potassium

[0052]In the mother liquor obtained from Example—1, 50 ml of acetonitrile is added and resultant solution is concentrated by distillation under vacuum and there after it is allowed to cool. Potassium salt of rosuvastatin obtained by filtration is crystalline form.