ASPECTS OF THE INTERACTIONS BETWEEN INDOMETHACIN AND NICOTINAMIDE IN SOLID DISPERSIONS

A series of indomethacin/nicotinamide binary system-melts were prepare d as models to study some aspects of the potential physico-chemical in teractions between indomethacin and nicotinamide. The comparative anal ysis of the data from FT-IR-and UV spectroscopy, DSC, X-ray diffractom etry and equilibrium solubility study showed that formation of complex es of different stoichiometry can take place in the solid state and in solution. The aqueous solubility of the assumed complexes of drug/car rier molar ratio above 1:1 (M/M) did not exceed the solubility of the pure indomethacin (IND) (treated), which was prepared as the model mel ts. The melts with a low drug content (e.g. 7.5 and 9.1% melts) were f ound to be in a metastable physical state probably due to the amorphou s nature of the indomethacin or its complex. They can be in situ trans formed into 1% indomethacin aqueous solution. (C) 1998 Elsevier Scienc e B.V. All rights reserved.