The aggregation behavior and formation of nanoparticles of oleoylchitosan in dilute aqueous solution

Abstract

Oleoylchitosans (O-chitosans) with different degrees of substitution (DS) were synthesized by reacting chitosan with oleoyl chloride. The chemical structures of the products were characterized by 1 H NMR and FT-IR. These results suggested the formation of an amide linkage between the amino groups of chitosan and the carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase became larger as the DS increased. All of the O-chitosans could reduce surface tension slightly. The critical aggregation concentration (CAC) of O-chitosans with DS 5%, 11%, and 27% were 79.43 mgL -1 , 31.6 mgL -1 , and 10 mgL -1 , respectively. Nanoparticles were prepared using an O/W emulsification method. The mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5% and 11% were around 327.4 nm and 275.3 nm, respectively.

Preparation and characteristic of lactose‐oleoylchitosan and the application of its self‐aggregates as drug delivery system

“…Being a long hydrophobic chain, oleoyl chain played the role of junction zones, which linked multiple polymer molecules together in intermolecular aggregate. 19 Consequentially, this would lead to increase of viscosity. On the other hand, the introduction of lactose, a highly hydrophilic and flexible arms, eventually led to decrease of the viscosity of the polymer.…”

“…Additionally, we could adjust the ratio of oleoyl chain to the lactose groups to get an ideal proportion which could form appropriate nanoparticles depending on the previous work. 19 Release behavior of DOX from the nanoparticles…”

“…1 Oleoylchitosan (OCH), 19 which we formerly prepared, had the similar potential capability of self-aggregation behaviors in aqueous solution. Furthermore, the oleoyl chain, possessing the lipophilic character, had the favor to contact with phospholipids bilayer of membrane and was likely to enter cell.…”

“…Hydrophobic chitosan derivatives modified by long chain fatty acyl have shown out huge potential application in drug delivery systems and have been investigated due to their strong property of forming self‐assembled nanoparticles, for example, cholesterol‐modified O ‐carboxymethyl chitosan,17 linoleic‐acid modified carboxymethyl‐chitosan,18 and stearic acid‐grafted chitosan oligosaccharide 1. Oleoylchitosan (OCH),19 which we formerly prepared, had the similar potential capability of self‐aggregation behaviors in aqueous solution. Furthermore, the oleoyl chain, possessing the lipophilic character, had the favor to contact with phospholipids bilayer of membrane and was likely to enter cell 20.…”

Preparation of self-assembled nanoparticles of chitosan oligosaccharide-graft-polycaprolactone as a carrier of bovine serum albumin drug

“…However, its use suffers severe limitations because it is insoluble owing to strong hydrogen bonding between the molecules of polysaccharides. Many CS-based amphiphilic copolymers composed of hydrophilic and hydrophobic segments have been reported through the reactions of amide group or hydroxyl group to improve solubility and expand its pharmaceutical appli-cations [1][2][3][4][5]. They have a tendency to form micelles through the self-assembled method above the critical micelle concentration (CMC) at the boundary between two phases, and can be used as target drug delivery carriers [6][7][8][9][10].…”