Crystallization Engineering in Aza-Steroid: Application in the Development of Finasteride

Novel and robust crystallization approach based on solid solution formation was developed for the purification of finasteride. This is an unprecedented approach that describes the use of pure finasteride <b>1</b> to purify different lots of finasteride <b>1</b> (impure) contaminated with dihydrofinasteride <b>2</b>