Encapsulation property of hyperbranched polyglycerols as prospective drug delivery systems

Hyperbranched polyglycerols (hbPGs) were investigated as nanocarriers to encapsulate and deliver guest molecules. 1H NMR titration and 1H–1H NOESY and fluorescence experiments were performed to study molecular interactions between hbPGs and Rhodamine B (RB). The results show that RB is entrapped in hbPGs by electrostatic interactions with hbPG etheric chains. Hydrogen bonds between etheric chains and the carboxyl group of RB induce the rotation of the phenyl vs. xanthene ring, further stabilizing the complex. hbPGs and RB interactions in water were also evaluated and compared to the interaction in d6-DMSO. The results reveal that the terminal glycerol units of hbPGs form a tight shell outside the interior parts in aqueous solution. 1H–1H NOESY studies of hbPGs with 5-Fu using surface modification suggest that this layer might be a main factor affecting the encapsulation and release of guest molecules.