Development and Characterization of Tetanus Toxoid Loaded Trimethylchitosan Chloride Nanoparticles for Nasal Immunization

Chitosan is an established mucoadhesive and absorption-enhancing polymers, but it has a pKa of 5.5, thus it is only soluble in acidic environments, where most of the amino groups are protonated. Recent studies have shown that only protonated soluble chitosan opens the tight junctions, facilitating the paracellular transport of hydrophilic compounds. To overcome the above problem a chitosan derivative, N, N, N-trimethyl chitosan chloride (TMC) has been synthesized and characterized, which shows higher solubility than chitosan in a broader pH range and is proved to be non-toxic. Tetanus toxoid (model antigen) loaded nanoparticles of TMC was prepared by ion gelation technique and were characterized for their size by transmission electron microscopy (TEM), zeta potential and zeta sizer. The antigen loading efficiency was found to be 52 % in TMC nanoparticles. In vitro release of tetanus toxoid was performed in phosphate buffer saline pH 7.4 and pH 5.6. In vivo study was accessed to study the antibodies production by ELISA (enzyme linked immuno-sorbant assay) and fluorescence microscopy was done to study mucoadhesive property of tetanus toxoid loaded TMC nanoparticles.