Cyclosophoraoses are a class of unbranced cyclic-(1longrightarrow2)-${\beta}$-D-glucans found in the Rhizobium species. Their unique cyclic structures and high solubility make them potent for inclusion complexation as a host for an insoluble guest molecule. A family of neutral cyclosophoraoses (DP 17-27) isolated from Rhizobium meliloti 2011 was used as a host for inclusion complexation with an insoluble guest drug, indomethacin. A high performance liquid chromatographic analysis indicated that the inclusion complexation of cyclosophoraoses greatly ehanced the solubility of indomethacin compared with ${\beta}$-cyclodextrin. The estimated value of the association constant of the complex in water for $\beta$-cyclodextrin and cyclosophoraoses was $523M^{-1} and 17,570M^{-1}$, respectively. NMR spectroscopy showed that the inclusion complex was characterized by the interaction of the indole ring moiety of indomethacin with the cavity of cyclosophoraoses.

Keywords: Cyclosophoraoses, inclusioncomplex, indomethacin, b-cyclodextrin