Processes for desolvating solvates of atorvastatin hemi-calcium and atorvastatin hem-calcium essentially free of organic solvent

Abstract

The present invention provides processes for removing organic solvent from crystals of atorvastatin hemi-calcium containing organic solvent. In one process, the organic solvent is displaced by vapor diffusion of water in a vessel maintained at elevated humidity. In a second process, the organic solvent is removed by fluidized bed drying. The present invention further provides atorvastatin hemi-calcium containing 1% or less organic solvent, which can be obtained from atorvastatin hemi-calcium that has been crystallized from an organic solvent-containing solution by practice of the processes of the invention.

1 . A process for desolvating a solvate of atorvastatin hemi-calcium comprising: 
 a) providing a solvate comprised of atorvastatin hemi-calcium and an organic solvent,    b) contacting the solvate with water vapor in a vessel whose interior is maintained at an elevated humidity relative to the outside of the vessel, and    c) recovering atorvastatin hemi-calcium essentially free of organic solvent.    
   
   
       2 . The process of  claim 1  wherein the recovered atorvastatin hemi-calcium is amorphous.  
   
   
       3 . Amorphous atorvastatin hemi-calcium containing 1 weight percent or less organic solvent prepared by the process of  claim 2 .  
   
   
       4 . Amorphous atorvastatin hemi-calcium containing 0.5 weight percent or less organic solvent prepared by the process of  claim 2.