Impact of Mixed ß-Cyclodextrin Ratios on Pluronic Rotaxanation Efficiency and Product Solubility.

Water-soluble polyrotaxanes have been prepared under heterogeneous conditions from mixtures of ß-cyclodextrin (ß-CD), 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD), methyl-ß-cyclodextrin, or 6-monoazido-ß-cyclodextrin with 4-sulfobutyl ether-ß-cyclodextrin (SBE-ß-CD) and Pluronic L81 copolymer modified with cholesterol end caps. Threading reactions gave polyrotaxane products in modest chemical yield that were reflective of the ß-CD feed ratios in the reaction. Polyrotaxanes containing mixtures of HP-ß-CD and SBE-ß-CD were screened and found to be biologically active in an in vitro model of Niemann-Pick Type C disease where they mobilize aberrantly stored cholesterol similarly to monomeric cyclodextrin controls.