NOVEL DERIVATIVES OF CYCLODEXTRINS, MODIFIED WITH POLY(ETHYLENE OXIDE) AND THEIR COMPLEXATION PROPERTIES

A new family of bouquet-like molecules based on cyclodextrins is descr ibed. These compounds were obtained by polymerization of ethylene oxid e. This reaction was initiated by primary and secondary hydroxyl group s of cyclodextrins, which constitute an organizing core. Analysis of s tructure and composition of conjugates based on alpha-CD and beta-CD w as performed using the data of MALDI-MS, GC-MS, and C-13-NMR spectra. Glass transition behavior of the conjugates shows that the above compo unds are amorphous. Complexation properties of the conjugates are desc ribed with respect to sodium 4-nitrophenolate and calcium acetylhomota urinate, which are used as guest molecules. Binding interaction betwee n cyclodextrins or their conjugates and sodium 4-nitrophenolate was st udied using differential absorption spectra. Association constants K-a between CD hosts and calcium acetylhomotaurinate composed of two equa l anionic moieties were studied using H-1-NMR spectroscopy. The values of binding constant for beta-CD were found to increase by more than 2 orders of magnitude than that of the corresponding system based on al pha-CD. alpha-CD was shown to form the inclusion complex with one anio nic moiety, whereas beta-CD produces a ternary complex with two anioni c moieties of CAHT. For PEO derivatives of CDs, K-a decreases as compa red with that of parent CD for both guests. These conjugates may be us ed as potent drug-delivery systems.