In this study, novel nanoparticles were prepared by polyelectrolyte complexation between heparin and chitosan on simple and mild conditions. The size, polydispersity, zeta potential, and morphology of the nanoparticles were characterized. Entrapment studies of the nanoparticles were conducted using bovine serum albumin (BSA) as a model protein. Specifically, the effects of the pH value of chitosan solution, chitosan molecular weight (MW), chitosan concentration, heparin concentration, and BSA concentration on the nanoparticle size, the nanoparticle yield, and BSA entrapment were studied in detail. We found that, the size and the yield of the nanoparticles were affected by the above factors. The nanoparticle yield played a crucial role in BSA entrapment, namely, more nanoparticles could encapsulate more BSA. At length, suitably high pH value of chitosan solution, moderate chitosan MW, increasing both heparin concentration and chitosan concentration at an optimal concentration ratio favored more nanoparticles formed and consequently a higher BSA entrapment efficiency.
In this study, carboxymethyl chitosan (CMC) hydrogel beads were prepared by crosslinking with Ca 2þ . The pH-sensitive characteristics of the beads were investigated by simulating gastrointestinal pH conditions. As a potential protein drug delivery system, the beads were loaded with a model protein (bovine serum albumin, BSA). To improve the entrapment efficiency of BSA, the beads were further coated with a chitosan/CMC polyelectrolyte complex (PEC) membrane by extruding a CMC/BSA solution into a CaCl 2 /chitosan gelation medium. Finally, the release studies of BSA-loaded beads were conducted. We found that, the maximum swelling ratios of the beads at pH 7.4 (17-21) were much higher than those at pH 1.2 (2-2.5). Higher entrapment efficiency (73.2%) was achieved in the chitosan-coated calcium-CMC beads, compared with that (44.4%) in the bare calcium-CMC beads. The PEC membrane limited the BSA release, while the final disintegration of beads at pH 7.4 still leaded to a full BSA release. Therefore, the chitosan-coated calcium-CMC hydrogel beads with higher entrapment efficiency and proper protein release properties were a promising protein drug carrier for the site-specific release in the intestine.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.