Chitosan nanoparticles with aluminium hydroxide gel as nasal delivery system for influenza vaccine

Abstract

In this study, the potential delivery system for nasal administration of Influenza vaccine was prepared by ionotropic gelation of chitosan (CS) with sodium tripolyphosphate pentabasic (TPP) and consequent conjugation with aluminium hydroxide gel. The preparation conditions influencing on physicochemical characteristics were evaluated. Bovine serum albumin (BSA) was used as model antigen for the evaluation prior to immunization study. The results demonstrated that the particle size decreased by decreasing of chitosan solution concentration with the optimum weight ratio of chitosan : TPP (3:1). The appropriate pH of chitosan solution at 4.5 resulted in slight decreasing of particle size while increasing the pH caused increasing the particle size and decreasing zeta potential. Moreover, the amount of tween 80 and aluminium hydroxide gel and order of mixing also affected the size. The obtained nanoparticles had spherical structure surrounded by fluffy coating of aluminium hydroxide gel and showed loading efficiency about 52 - 57%. The integrity of entrapped protein was maintained as shown by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and circular dichroism. The testing in RMPI 2650 cells showed that the particulate formulations could not open the tight junctions but dramatically induced cellular uptake. The formulations selected for further studies in animals were relatively non-toxic to the cell culture. Upon i.n. administration, influenza antigen loaded chitosan nanoparticles conjugated with aluminium hydroxide gel induced higher immune response than other i.n. formulations. The i.n. vaccination response was not different from those induced by i.m. vaccination (p>0.05). Moreover, only conjugated formulation could induce S-IgA in all mice among the tested formulations.