SOLID-STATE INVESTIGATION OF FLUOCINOLONE ACETONIDE

Three crystalline modifications of fluocinolone acetonide, A, B and C, were characterized by means of FTIR, DSC, TG-FTIR, MICRO-FTIR and X-r ay diffractometry. They were easily differentiated by their IR absorpt ion bands in the 3600-3400 cm(-1) range. The thermal behaviour was als o elucidated using combined techniques; thermomicroscopy and thermogra vimetry coupled with Fourier transform infrared spectroscopy were foun d to be very useful tools for a better understanding of thermal events . On heating, form A and C were fully converted into form B. Polymorph A was found to be enantiotropically related to B, while form C was mo notropically related to B. The existence of three polymorphs was confi rmed by means of their different X-ray diffraction patterns. Detailed methods of preparation of the three modifications are also described. (C) 1997 Elsevier Science B.V.