FORMAS CRISTALINAS DE 11ß-(4-ACETILFENIL)-20,20,21,21,21-PENTAFLUORO-17-HIDROXI-19-NOR-17ALFA-PREGNA-4,9-DIEN-3-ONA

REFERIDA A UNA FORMA CRISTALINA DE 11ß-(4-ACETILFENIL)-20,20,21,21,21-PENTAFLUORO-17-HIDROXI-19-NOR-17ALFA-PREGNA-4,9-DIEN-3-ONA, BAJO LAS FORMAS POLIMORFICAS I Y II, DONDE EL DIFRACTOGRAMA DE RAYOS X EN POLVO PRESENTA LINEAS CON VALORES d=21,4 Å, 7,7 Å, 5,8 Å Y 5,3 Å Y EL DE LA FORMA POLIMORFICA II PRESENTA LINEAS CON VALORES DE d= 5,1 Å, 7,1 Å Y 5,6 Å. TAMBIEN ESTA REFERIDA A UN PROCEDIMIENTO DE PREPARACION DE DICHAS FORMAS CRISTALINAS The present invention relates to crystalline forms of 11 -(4-acetylphenyl)-20, 20,21,21,21-pentafluoro-17-hydroxy-19-nor-17 -pregna-4,9-dien-3-one. The invention relates in particular to two crystalline ansolvate/anhydrate forms of this compound, polymorphs I and II. However, the present invention also relates to crystalline solvates, for example methanol and ethanol solvates of 11 -(4-acetylphenyl)-20,20,21,21,21-pentafluoro-17-hydroxy-19-nor-17 -pregna-4,9-dien-3-one as precursors for preparing these two polymorphs I and II. Processes for preparing polymorph I by displacement crystallization or by trituration are described. Selection of the last solvent before formation of the ansolvate can be based on the differences in the purification behaviour of the individual solvates of 11 -(4-acetylphenyl)-20,20,21,21,21-pentafluoro-17-hydroxy-19-nor-17 -pregna-4,9-dien-3-one. Polymorph I according to the invention is particularly suitable for the manufacture of medicinal products.