Chitosan-alginate nanoparticles for antisense delivery: Formulation, Optimization and invitro characterization

Chitosan is a natural cationic polysaccharide obtained by the N-deacetylation of chitin, a product found in the shells of crustaceans. It is widely used as a carrier in gene delivery oral protein delivery and controlled release systems [1].Alginates are random, linear and anionic polysaccharides consisting of linear copolymers of α-L-guluronateand β-D-mannuronate residues. Alginates have a long history of use in numerous biomedical applications, including drug delivery systems, as they are biodegradable, biocompatible and mucoadhesive polymers [2].Chitosan and alginate are two biopolymers that have received much attention and have been extensively studied for such use [3]. Chitosan being a cationic polymer has been used for the production ofmicrospheres and nanoparticles by ionotropic gelation with negatively charged polymers and there are many chitosan–polyanion complexes that have been investigated as drugdelivery systems for drugs, proteins, DNA and other oligonucleotides, with encouraging results [3-5]. Among the various types of chitosan–polyanion complexes reported in the literature, the combination of chitosan and sodium alginate is considered to be the most interesting for colloidal carrier systems [3].Chitosan–alginate (CS–ALG) polyionic complexes are formed through the ionic gelation via interactions between the carboxyl groups of alginate and the amine groups of chitosan. The complex protects the encapsulant, has biocompatible and biodegradable characteristics, and limits the release of encapsulated materials more effectively than either alginate or chitosan alone [3]. A further advantage of this delivery system is its non-toxicity permitting the repeated administration of therapeutic agents. CS–ALGmicrospheres or beads have been widely studied for the encapsulation of several drugs, proteins, cells and oligonucleotides, with promising results [3,4–6]. Despite the attractive properties offered by CS–ALG system, its development and application in the submicron scale has scarcely been studied [3,4–6 ].In the present research, we report a slightly modified method to prepare CS–ALG nanoparticles based on the formation of a polyionic complex between the two biopolymers. The current study aimed at developing and optimizing a nanoparticulate formulation of EGFR antisense oligonucleotides in CS-ALG nanoparticles using design of experiments. And effect of factors like polymers ratios, crosslinker ratios, pH and N/P ratio on some responses such as nanoparticles size, Zeta potential and EGFR antisense loading efficacy was investigated.