Sulfoalkyl ether β-cyclodextrin derivatives:: Synthesis and characterizations

A series of sulfoalkyl ether beta-cyclodextrin derivatives, including sulfoethyl, sulfopropyl and sulfobutyl ethyl beta-cyclodextrins, have been synthesized and characterized. Each sulfoalkyl ether beta-cyclodextrin is a mixture of various degrees of substitution and different positional isotherms. Elemental analysis, H-1 NMR, MS, and Differential Scanning Calorimetry analysis were used to determine the average degree of substitution for each beta-cyclodextrin derivative. The average degrees of substitution are 3.4, 1.6 and 2.5 for sulfoethyl, sulfopropyl and sulfobutyl ether beta-cyclodextrin, respectively. The water solubility of these derivatives is substantially higher than that of beta-cyclodextrin. H-1 NMR indicates that sulfoethyl ether cyclodextrin may have major substitution on the secondary hydroxyl group while the major substitution in sulfopropyl and sulfobutyl ether beta-cyclodextrin could be on the primary hydroxyl group. MS spectra show that no more than one substitution occurred on a single glucose unit.