| 摘要 |
<p>A process for producing polymorphic form I of 17beta-(N-tert-butyl carbamoyl)-4-aza-5alpha-androst-1-en-3-one, comprising the steps of crystallization of finasteride a) in a mixture of ethyl acetate and water, wherein the amount of water in the solvent mixture is at most 3.5 mg/ml, b) in a mixture of iso-propyl acetate and water, wherein the amount of water in the solvent mixture is at most 1.6 mg/ml, at an ambient temperature of about 25 degree, the resultant solid phase is recovered and the solvent is removed there from. The invention further relates to a process for producing polymorphic form II, comprising crystallization of finasteride from the mixture of organic solvent and water followed by recovering the solid phase, and removing the solvent.</p> |
