Preparation and characterization of Furosemide-Eudragit controlled releasesystems

Solid dispersions and physical mixtures were prepared and characterized by X-ray diffraction, infrared spectroscopy, electronic microscopy and dissolu tion rate studies. The characterization with X-ray diffraction showed a tra nsition from the crystalline to the amorphous phase. A new phase near 50% F urosemide concentration with both types of carriers was present. From infra red spectroscopy strong interactions between amine and carbonyl groups from both the Furosemide and the polymers were found. Electronic microscopy ana lysis showed that the Furosemide changed its crystalline habit from needle to a new spherical phase, with diameter near to 1 mu m. Solid dispersions w ere prepared in order to modify the system characteristics. The Furosemide dissolution rate was determined in order to follow the behavioural changes of the system. Scanning electron microscopy showed the presence of micro sp heres within the polymeric matrix, and the channels formed due to the Furos emide dissolution inside the Eudragit: this fact modified the release patte rn of the Furosemide system. (C) 2000 Published by Elsevier Science B.V. Al l rights reserved.