Properties and the Inclusion Behavior of 6-O-[alpha]-D-Galactosyl- and 6-O-[alpha]-D-Mannosyl-cyclodextrins

The novel heterogeneous branched cyclodextrins (CDs), 6-O-α-D-galactosyl-α, -β, and -γCDs (Gal-α, -β, and -γCDs) and 6-O-α-D-mannosyl-α, -β, and -γCDs (Man-α, -β, and -γCDs) dissolved sufficiently in water and in 10-50% (v/v) methanol aqueous solutions, as did the homogeneous branched CDs, 6-O-α-D-glucosyl-α, -β, and -γCDs (Glc-α, -β, and -γCDs). The solubilities of heterogeneous branched CDs were higher than those of each parent non-branched CDs. The hemolytic activities of heterogeneous and homogeneous branched CDs were lower than those of each parent non-branched CDs and the hemolytic activity became weaker in the order of non-branched CD>Man-CD>Glc-CD>Gal-CD in each series of α, β, and γCD. AL type solubility-phase diagrams were displayed in the formation of inclusion complexes of the guest compounds of small size (methyl benzoate, estriol, and dexamethasone) with Gal-, Man-, and Glc-CDs, and marked differences among the three kinds of branched CDs could not be detected. However, solubility-phase diagrams between these branched CDs and the insoluble guest compounds of large cyclic structure (cyclosporin A, tacrolimus, and amphotericin B) showed AP type, and the improvement of water solubilities of these guest compounds with three kinds of branched CDs was enhanced in the order of Man-CDs>Glc-CDs>Gal-CDs.