SOLID-STATE BETA-CYCLODEXTRIN COMPLEXES CONTAINING INDOMETHACIN, AMMONIA AND WATER - II - SOLUBILITY STUDIES

In a previous report five unique complexes were prepared and character ized containing beta-cyclodextrin, indomethacin, ammonia and water. In this study the solubility, dissolution behavior, complex-binding cons tant, crystallinity and enthalpy were assessed. The results show indom ethacin solubility was improved by complex formation with beta-cyclode xtrin. There was little difference among the various complex solubilit ies. Indomethacin dissolution was improved by complex formation with t he exception of one complex. Indomethacin dissolution profiles were fo und to differ and were unrelated to either the complexed indomethacin content or binding constant. Indomethacin dissolution profiles were fo und to be related to the complex crystallinity and enthalpy. The compl ex-binding constants were found to support a theory reported previousl y that beta-cyclodextrin ring cavity solvation was the predominant fac tor responsible for complex formation. (C) 1998 Elsevier Science B.V. All rights reserved.