Structures from powders: diflorasone diacetate.

Diflorasone diacetate, a steroid anti-inflammatory drug (marketed as Diacort or Florone by Pfizer) and used in the treatment of skin disorders, can be prepared as anhydrous form, DD1 (as deposited in the US pharmacopoeia), or as a monohydrated phase, DDW. Heating the DDW form above 90 degrees C, a mixture of DD1 and of a new anhydrous polymorph, DD2 is obtained. Further heating of this mixture, or of pure DD1, up to 230 degrees C (only a few degrees before melting!), generates an elusive anhydrous DD3 polymorph.

A degradation product of halobetasol propionate: characterization and structure.

Degradation of halobetasol propionate was observed in the presence of bases. A single cyclization product was isolated and fully characterized by MS, NMR and X-ray crystallography.