Interconversion studies of betamethasone acetate polymorphs.

The polymorph interconversions of Betamethasone Acetate (BA) were studied under various pharmaceutical conditions, such as grinding, heating and suspending in water, based on differential scanning calorimetry, thermogravimetric analysis, and X-ray powder diffraction. There existed enantiotropic relationships between the three polymorphs of BA, which were named form II, Ialpha, and Ibeta work, respectively. It was concluded that form II was the most stable form when suspended in water.