This study is devoted to developing amphiphilic, random glycopolymers based on phenylboronic acid, which self-assemble to form nanoparticles (NPs), as a glucose-sensitive agent. Maleimide-glucosamine was copolymerized with 3-acryl aminophenylboronic acid in methanol at 70 degrees C. Using the nanoprecipitation method, NPs with a narrow size distribution were successfully generated. Transmission electron microscopic analysis showed that the NPs were well dispersed as individual, spherically shaped particles. The swelling behavior of the NPs and the in vitro release profiles of insulin at different glucose concentrations revealed definite glucose sensitivity of the glycopolymers. Further, circular dichroism spectroscopy demonstrated that the overall tertiary structure of the released insulin was not altered compared with standard insulin. The analysis of relative cell proliferation suggested that the glycopolymer NPs had good biocompatibility. The glycopolymers that responded to changes in the glucose concentration of the surrounding environment are being aimed for use in self-regulated insulin delivery.

The purpose of this work was to investigate chitosan-N-acetyl-L-cysteine (chitosan-NAC) nanoparticles as a potential carrier system for the nasal delivery of insulin. For the study, we used insulin-loaded chitosan-NAC nanoparticles (140-210 nm in diameter) prepared by in situ gelation with tripolyphosphate (TPP), with positive zeta potential values of +19.5-31.7 mV and insulin loading capacities of 13-42%. The physicochemical properties of the nanoparticles were affected by the number of thiol groups present. Mucoadhesive properties, which were evaluated by measuring the in vitro absorbed mass of mucin, of chitosan-NAC nanoparticles were >1.8-fold that of unmodified chitosan nanoparticles. In aqueous solution, chitosan-NAC nanoparticles exhibited fast swelling behavior. Insulin was released from chitosan-NAC nanoparticles in vitro in an initial burst followed by slow release. Intranasal administration of chitosan-NAC nanoparticles in rats enhanced the absorption of insulin by the nasal mucosa compared with unmodified chitosan nanoparticles and control insulin solution. In light of these observations, the novel thiolated chitosan nanoparticles represent a promising vehicle for nasal insulin administration.

No abstract

No abstract