Development of polysaccharide-capped niosomes for oral immunization of tetanus toxoid

Niosomes appear to be a promising and potential carrier system for oral antigen delivery. In the present study, polysaccharide-capped-niosomes were prepared, characterized and evaluated for immunostimulating potential. Tetanus toxoid (TT) antigen was encapsulated in the niosomes using the reverse phase evaporation method and coated with a pullulan derivative i.e. O-palmitoyl pullulan (OPP). Synthesized OPP was characterized by IR and proton NMR spectroscopy. The prepared niosomes were evaluated for size, shape, encapsulating efficiency and stability in simulated gastric fluid (pH 1.5). Serum IgG antibody level was measured to assess the immune stimulating effect of these carriers following oral administration. OPP-capped TT loaded niosomes could produce better humoral response as compared to their plain counterpart. Further, OPP appended niosomes produce immune response almost equivalent to intramuscularly given alum adsorbed TT. Mucosal IgA titers suggest polysaccharide-capped niosomal systems could be a potential oral vaccine delivery system.