Mucosal delivery of vaccines: role of mucoadhesive/biodegradable polymers

Majority of infectious microorganism make their gateway to the host through mucosal surfaces, such as gastrointestinal tract, nasal and vaginal tract. Mucosal immune response structured as sIgA can effectively prevent the attachment and invasion of the microorganism from mucosal surface and thereby serves as an efficient tool against infectious disease. There has been an increased demand for the development of novel vaccine that leads to the induction of immune response in systemic circulation as well as at mucosal surfaces against infectious disease. Mucosal delivery of vaccine provides basis for induction of both mucosal as well as systemic immune responses against the infectious organisms. However, a variety of factors such as mucociliary clearance, presence of deteriorating enzymes, pH extremes (GIT), low permeation and metabolic degradation limit the mucosal delivery of vaccine. Numerous strategies have been explored in the meadow of mucosal vaccination for the purpose of efficient antigen delivery through mucosal route(s). Polymeric carrier(s) such as nanoparticles and microparticles loaded with the antigen can serve as the basis for creation of important formulations for improved vaccine. Biodegradable and mucoadhesive polymeric carrier(s) seems to be most promising candidate for mucosal vaccine delivery. Several polymers from natural and synthetic origin, such as polylactide-co-glycolide, chitosan, alginate, carbopol, gelatin etc., have been explored for the efficient mucosal vaccine delivery and significant results have been obtained. This review outlines the polymers used in mucosal vaccine delivery with special reference to mucoadhesive/biodegradable polymers. This article also covers the recent patent granted in the field on polymeric carrier mediated mucosal vaccination.