Polyelectrolyte complexes of sodium alginate with chitosan or its derivatives for microcapsules

Abstract

Chitosan, a cationic polysaccharide, was heterogeneously deacetylated with a 47% sodium hydroxide solution and followed by a homogeneous reacetylation with acetic anhydrides to control the N-acetyl content of the chitosan having a similar molecular weight. The chitosans having different degrees of N-acetylation were complexed with sodium alginate, an anionic polysaccharide, and the formation behavior of polyelectrolyte complexes (PECs) was examined by the viscometry in various pH ranges. The maximum mixing ratio ( R max ) increased with a decrease in the degree of N-acetylation of the chitosan at the same pH, and with a decrease in pH at the same degree of N-acetylation. Similarly, N-acylated chitosans were also prepared. The Nacyl chitosans scarcely affected the formation behavior of PECs with sodium alginates. For the application of the PECs produced, the microencapsulation of a drug was performed and the release property of drug was tested. The microcapsules were prepared in one step by the extrusion of a solution of guaifenesin and sodium alginate into a solution containing calcium chloride and chitosan through interpolymeric ionic interactions. The drug release during the drug-loaded microcapsules storage in saline was found to depend on the pH where the microcapsules were formed and the kind of Nacyl groups introduced to the chitosan.

Characterization of insulin-loaded alginate nanoparticles produced by ionotropic pre-gelation through DSC and FTIR studies

“…Therefore, at pH 4.2 it is possible that nanoparticles presented a stronger robustness that at pH 4.7 and more that pH 5.2, as analyzed. The interaction between alginate and chitosan is known to be pH-dependent and stronger complexes were also obtained at pH around 4.5-5.0 (Lee et al, 1997;Liu et al, 2004).…”

“…Many studies have been published on individual chitosan-alginate systems (De & Robinson, 2003;Lee, Park, & Ha, 1997). Although parameters such as the molecular weight, temperature, and pH have been studied to some extent, most of these studies are performed under specific and limited pH and stoichiometric conditions.…”

Polyelectrolyte Biomaterial Interactions Provide Nanoparticulate Carrier for Oral Insulin Delivery

“…For ALG-CHIT complexes, the asymmetric -C-O-stretching disappeared and a new broad band with strong peak of amine coupled with amide II appeared, indicating that NH + 3 present in chitosan interacts with -COO − of alginate. Electrostatic binding resulted between alginate and chitosan, since at working pH, alginate was an anionic polymer in solution (Murata, Miyamoto, and Kawashima 1996) and chitosan was a cationic polymer, and the resulting complex is well documented (Becherán-Marón, Peniche, and Argüelles-Monal 2004;Gaserod, Smidsrod, and Skjak-Braek 1998;Lee, Park, and Ha 1997;Sankalia et al 2006;Tapia et al 2004).…”

Preparation and Characterisation of Phenytoin-Loaded Alginate and Alginate-Chitosan Microparticles

“…This yields particles with a complex alginate-chitosan membrane surrounding a liquid alginate core. Gelling of the core is achieved by having calcium chloride in chitosan solution either during the formation of the particles (Huguet, Neufeld, and Dellacherie 1996;Huguet et al 1994;Lee, Park, and Ha 1997;Overgaard et al 1991) or by treating the liquid core particles with the salt after the membrane has been formed (Huguet et al 1994).…”