Preparation of coated nanoparticles for a new mucosal vaccine delivery system

Abstract

It has been found that the adsorption of antigens onto chitosan particles is an easy and unique mild loading process suitable to be used with vaccines. In order to increase the stability of this particles and to prevent an immediate desorption in gastrointestinal fluids, a coating process with sodium alginate was developed. One of the challenges of this developing process was to keep the particles in the nanosized range in order to be taken up by M-cells of the Peyer's patches. The observed inversion of the particles' zeta potential values after coating suggested the presence of an alginate coating layer. These results were confirmed by FTIR and DSC techniques. Additionally, in vitro release studies showed that the presence of the alginate layer around the particles was able to prevent a burst release of loaded ovalbumin and to improve the stability of the nanoparticles in simulated intestinal fluid at 37 degrees C. The optimisation of the coating process resulted in 35% (w/w) for the loading capacity of the coated particles. SEM investigations confirmed a suitable size of the coated nanoparticles for the uptake by M-cells.

Development and in vitro/in vivo evaluation of Zn-pectinate microparticles reinforced with chitosan for the colonic delivery of progesterone

“…Also, a small exothermic deviation from baseline at around 240 C was noticeable, indicating the start of pectin chains depolymerization (Maestrelli et al, 2008a). Chitosan ( Figure 3C) shows a broad endothermic peak at $95 C due to the evaporation of absorbed water and a sharp exothermic peak starting at 280 C and gaining its maximum at 310 C due to chitosan degradation (Borges et al, 2005). The thermograms of both empty ( Figure 3D) and PG-loaded MPs ( Figure 3E) show disappearance of the degradation exothermic peaks of chitosan at 310 C and of pectin at 240 C, as well as pectin endothermic peaks which could be attributed to the electrostatic interactions between pectin and chitosan.…”

Development and characterization of new insulin containing polysaccharide nanoparticles

“…However, due to the labile physicochemical properties of proteins, gentle nanoencapsulation conditions must be provided to assure the maintenance of their structural bioactivity. Particular attention has been given to protein-loaded chitosan-based nanoparticles [5][6][7]. Chitosan, an unbranched polyamine of d-glucosamine and N-acetyl glucosamine molecules, is characterized for its biodegradable, non-toxic and biocompatible properties [8] providing several biomedical, pharmaceutical and food applications.…”

Chitosan nanoparticles: a survey of preparation methods

“…The use of desolvating agents to produce chitosan particles was reported for the first time for the preparation of micron-sized carriers (Berthold et al 1996) but, nowadays, this procedure is frequently applied to the production of chitosan nanoparticles. Substances such as sodium sulfate (Mao et al 2001, Borges et al 2005, Atyabi et al 2009) and non-solvents miscible with water, like acetone (Agnihotri and Aminabhavi 2007), have been proposed as precipitating agents, although the former has been used more frequently. The preparation of chitosan nanoparticles by this method is very simple and mild as it involves the dropwise addition of the solvent competing agent of greater hydrophilicity (e.g.…”