Solid-state β-cyclodextrin complexes containing indomethacin, ammonia and water.: II.: Solubility studies

In a previous report five unique complexes were prepared and characterized containing beta-cyclodextrin, indomethacin, ammonia and water. In this study the solubility, dissolution behavior, complex-binding constant, crystallinity and enthalpy were assessed. The results show indomethacin solubility was improved by complex formation with beta-cyclodextrin. There was little difference among the various complex solubilities. Indomethacin dissolution was improved by complex formation with the exception of one complex. Indomethacin dissolution profiles were found to differ and were unrelated to either the complexed indomethacin content or binding constant. Indomethacin dissolution profiles were found to be related to the complex crystallinity and enthalpy. The complex-binding constants were found to support a theory reported previously that beta-cyclodextrin ring cavity solvation was the predominant factor responsible for complex formation. (C) 1998 Elsevier Science B.V. All rights reserved.