Development and Characterization ofMucoadhesive HBsAg PLGA Microsphere forNasal Vaccine Delivery

The purpose of the study was to evaluate the mucoadhesive property of Hepatitis B surface antigen (HBsAg) loaded surface modified poly(lacticco- glycolic acid) (PLGA) microspheres for nasal vaccine delivery. The surface modification was carried out using coating material such as chitosan, Trimethyl chitosan and N-trimethyl chitosan and Ncarboxymethyl chitosan (TMC-CMC). The developed formulations were characterized for surface morphology, particle size, zeta potential, entrapment efficiency, structural integrity, In vitro mucoadhesion study and mucin adsorption ability. PLGA microspheres without surface modification demonstrated negative zeta potential, whereas Chitosan and its derivatives coated microspheres showed higher positive zeta potential. Results indicated that combination of TMC-CMC coated microspheres demonstrated substantially higher mucin adsorption and longer time of mucoadhesion when compared to chitosan and TMC coated microspheres and uncoated PLGA microspheres. Both uncoated and coated PLGA microspheres showed initial burst release followed by prolonged release pattern. The immuno-adjuvant ability of various formulations was determined on the basis of specific antibody titer observed in serum and secretions of mice. In vivo immunogenicity studies showed increased anti- HBsAg titer with TCC-CMC coated PLGA microspheres as compared to other coated and uncoated PLGA microspheres. To conclude, TCC-CMC coated PLGA microspheres could be a promising carrier targeted delivery for HBsAg in nasal mucosa.