Interactions of oxyphenbutazone with different cyclodextrins in aqueous medium and in the solid state.

The interactions between a nonsteroidal anti-inflammatory drugs, oxyphenbutazone (OPB), with two cyclodextrins, beta-cyclodextrin (beta-CD) and gamma-cyclodextrin (gamma-CD), have been studied in an aqueous medium and in the solid state. Differential scanning calorimetry, hot stage microscopy, thermogravimetric analysis and X-ray diffraction (XRD) powder have been the techniques used to characterize the interactions in the solid state. Although OPB forms inclusion compounds with beta- and gamma-CD in the aqueous medium, only the OPB/gamma-CD inclusion compound was obtained in the solid state by the kneading method. The XRD powder used at different temperatures has proven be a useful tool in characterizing the behaviour of these binary systems.