PHASE-TRANSFORMATIONS AND STABILIZATION OF METASTABLE STATES OF MOLECULAR-CRYSTALS UNDER MECHANICAL ACTIVATION

The influence of mechanical treatment on polymorphism of sulphathiazol e and piroxicam has been studied. It was shown by thermal analysis, X- ray diffraction and IR-spectroscopy methods that mechanical treatment leads to the partial amorphization of the drugs and III<->I polymorphi c transformations of sulphathiazole. The changes in molecular structur e of piroxicam were suggested. The mechanical activation of drugs in m ixtures with polyvinylpyrrolidone allowed us to obtain stable specimen s of the drugs with elevated rates of dissolution and apparent solubil ity as compared to intact and mechanically activated substances.