Acid-catalyzed hydrolysis of maltosyl-β-cyclodextrin

Article abstract of DOI:10.1002/jps.2600810915

Maltosyl-β-cyclodextrin was hydrolyzed via two pathways in acidic solution: (1) ring opening to give noncyclic oligosaccharides and (2) cleavage of maltose in the branched residue to give glucosyl-β-CyD and glucose. Ring opening was ~2-3 times faster than maltose cleavage because of the multiple hydrolysis sites of the β-cyclodextrin (β-CyD) ring (seven glycosidic linkages) compared with only one reaction site of the maltose residue in the branch. Values of the enthalpy and entropy of activation of the hydrolyses were positive and in the range reported for maltose, a result indicating that the hydrolyses proceeded according to the A-1 mechanism (i.e., unimolecular decomposition). The α-1,6-glycosidic bond of branched β-CyDs connecting β-CyD and branched sugar moieties resisted hydrolysis; this property is a potential pharmaceutical advantage because the parent β- CyD, which has low aqueous solubility, would not precipitate after hydrolysis.