Characterization of Sesquiterpene Polygodial-Beta Cyclodextrin Inclusion Complex

Polygodial is a sesquiterpene drimane isolated from the genus Drimys, whichexhibits anti-asthmatic, anti-allergic, anti-inflammatory and antinociceptive effects.We have prepared a polygodial--cyclodextrin inclusion complex for furtherpharmacological studies. The inclusion complex was synthesized by co-precipitationand analyzed by Thermogravimetric Analysis, showing a decrease in the number ofwater molecules of hydration in relation to the native -cyclodextrin. DifferentialThermogravimetric Analysis indicated a peak corresponding to the evaporation ofpolygodial. With Differential Scanning Calorimetry, the melting peak to polygodial was not observed, however, there was an increase in the energy of vaporization of the water molecules in relation to native -cyclodextrin. Using a Scanning Electron Microscopy a clear difference in the morphology of crystals of the inclusion complex and native -cyclodextrin could be seen. The association constant between polygodial and -cyclodextrin, measured by UV spectroscopy was 1,006 M^-1 at 37 °C, pH 7.0 and ionic strength 0.2 M, following stoichiometry 1:1.