Highly Soluble β-Cyclodextrin Derivatives

β-Cyclodextrin is an inclusion complexing agent produced on industrial scale. The low solubility of its complexes is a serious disadvantage in many cases. Substituted β-Cyclodextrin derivatives are characterized by much higher solubility. Among methylated derivatives the heptakis-di-O-methyl-β-Cyclodextrin deserves special attention. In its aqueous solutions many poorly soluble or practically insoluble compounds can be dissolved, whereas the solubility enhancement factor is between 3 and 1 200 depending on the substance. Aqueous injectable solutions can be prepared from highly lipophilic compounds, enzymatic reaction rate of lipophilic substrates can be strongly accelerated, biological absorption of drugs or fat-soluble vitamins can be enhanced and vaccine production can be augmented up to 100-fold. Methylated cyclodextrins are able to act as solvents by forming watersoluble inclusion complexes and as phase-transfer catalysts at free radical polymerization. Low molecular cyclodextrin-polymers with molecular weight between 2 000 and 10 000 behave similarly. They are very well soluble, retaining their complexing ability. On account of the macromolecular character the diffusion of dissolved and complexed substances is considerably decelerated. By including into a chiral cavity the entrapped molecules become optically active oriented, and therefore their reactions are sterically controlled.