Polymorphism of Clopidogrel Bisulphate (Form I and Form II)

Clopidogrel bisulfate is a platelet aggregation inhibitor, medicine for prophylaxis and the treatment of thrombosis by acting as a platelet aggregation inhibitor. It has now been discovered that clopidogrel hydrogen sulfate can exist in different polymorphic crystalline forms which differ from :
  1. stability
  2. physical properties
  3. spectral characteristics
  4. process for their preparation.
The dextrorotatory isomer of clopidrogel bisulfat (Form II) has an excellent platelet aggregation inhibiting activity whereas the levorotatory isomer is less active and less well tolerated (Form II).