Enhancement of immunopotentiation using tetanus toxoid-based nanoparticulate dissolvable microneedles

The main objective of the present study was to prepare and evaluate dissolvable microneedle patch containing nanoparticles of tetanus toxoid without the use of any adjuvant and its immunopotentiation activity. Immunization with microneedles is a novel approach in vaccines delivery with advantages such as convenience, simple, and non-invasive therapy. The gelatin nanoparticles were prepared by a layer-by-layer coating method using polystyrene sulfonate (PSS), polyallylamine hydrochloride (PLA), and PLGA. The filtered gelatin nanoparticles were later dispersed in the aqueous PVP K10 solution and integrated into a mold to develop microneedles. The nanoparticles and their dissolvable microneedle patches were evaluated using particle size, surface charge, entrapment efficiency, SEM analysis, in-vitro, and in-vivo studies. The particle size was found in the order of PLGA-coated nanoparticles > layered gelatin nanoparticles > aminated gelatin nanoparticles > gelatin nanoparticles and aminated gelatin nanoparticles showed maximum entrapment efficiency (92.6 ± 3.25%). The microscopic SEM images showed the spherical-shaped particle formation, verifies that the nanoparticles were formed. The gelatin nanoparticles followed the prolonged release for the period of 8 h whereas the nanoparticle-loaded dissolvable microneedles showed the controlled release pattern for 24 h. Aminated nanoparticulate microneedle showed the highest antibody production against tetanus toxoid. Hence, the nanoparticulate dissolvable microneedles-based immunopotentiation can be used as an alternative for delivery of tetanus toxoid.