β-Cyclodextrin grafting hyperbranched polyglycerols as carriers for nasal insulin delivery

We prepared a β-CD functionalized hyperbranched polyglycerol (HPG) with the purpose of enhancing the nasal transport of insulin in rats. Insulin-loaded HPG-g-CD nanoparticles (NPs) were prepared and the size of the NPs ranged from 198 to 340 nm with a positive charge. The NPs exhibited a great capacity of associating insulin, reaching the efficiency as high as 88.21%. In vitro release showed that the release rate of insulin was much faster under acidic condition than physiological condition. In vitro cytotoxicity against Caco-2 cells showed that HPG-g-CDs had good biocompatibility. The in vivo evaluation in rats demonstrated that insulin-loaded HPG-g-CD NPs had the ability to significantly decrease the blood glucose concentrations. Furthermore, the capability of HPG-g-CD NPs to cross the nasal mucosal epithelia was proved by confocal laser scanning microscopy (CLSM). Consequently, the results suggest that the HPG-g-CD NPs are promising carriers for nasal insulin delivery.