FORMATION OF INCLUSION COMPLEX OF ANTI-INFLAMMATORY TRITERPENOID CABRALEONE (DN12) WITH HYDROPHILIC BETA CYCLODEXTRIN POLYMER (β-CD-P)

The main objective of this study was to improve the solubility of the triterpenoid cabraleone (DN12) and to investigate the anti-inflammatory activity of the complex. DN12 was stabilized by a complex formation with β-cyclodextrin polymer (β-CD-P) in a molar ratio of 1.0:1.0. The DN12 extract and the cyclodextrin complex have been equilibrated in ethanol at 25°C for approximately 24 h. The β-cyclodextrin-polymer complex (β-CD-P-DN12) was characterized by a combination of experimental methods including ultraviolet-visible spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, infrared and nuclear magnetic resonance. The formation of the complex with β-cyclodextrin-polymer was confirmed by the use of five analytical tools. In-vivo anti-inflammatory activity, using 1 % of the carrageenan-induced rat paw oedema method of the β-CD-P-DN12 complex compared to that of DN12 alone was studied. The results showed that inclusion complex formation β-CD-P-DN12 improved stability and solubility in aqueous solution compared to free DN12. The results of the in-vivo study showed that the β-CD-P-DN12 inclusion complex exhibited different pharmacokinetics as compared to free DN12 after injection into the rat paw. The anti-inflammatory activity of DN12 triterpenoid appears earlier when it was complexed within the beta cyclodextrincavity of polymer as compared to free DN12.