Physical characteristics of inclusion compounds of 5-ASA in α and β cyclodextrins

Inclusions in alpha- and beta-cyclodextrins (CD) of 5-amino salicylic acid (5ASA), a light and oxygen sensitive drug, were prepared by a kneading method. The inclusions were studied in aqueous solutions and the solid state and compared to physical mixtures by several methods: differential scanning microscopy (DSC), thermomicroscopy, X-ray diffraction, scanning electron microscopy and mass spectrometry. Studies in aqueous solutions did not reveal the inclusion phenomena with alpha-CD. The stability of inclusion of 5ASA with beta-CD was very low in solution. The studies performed in solid state show that 5ASA may be included preferentially in beta-CD. Our data allow us to suggest the usefulness of a beta-CD-based dosage form to enhance the stability of 5ASA. (C) 1998 Published by Elsevier Science B.V. All rights reserved.