Single dose vaccine delivery system of tetanus toxoid formulation based on chitosan microspheres

Biodegradable polymers such as Chitosan or PLGA has been used for sustain release of vaccines for prolonged period. To develop single dose vaccine delivery system of tetanus toxoid using chitosan microspheres. Different batches, 1%, 2% and 3% of chitosan microspheres (CM) were prepared by emulsion cross-linking method using glutaradehyde saturated toluene (GST). The tetanus toxoid (TT) was loaded with 1%, 2% and 3% of CM by adsorption method. Percentage of TT absorbed in 1%, 2% and 3% CM were determined by Limes flocculation method. In vitro release of adsorbed TT from 1%, 2% and 3% CM were performed with PBS (pH 7.4) and evaluated by ELISA assay using purified guinea pig IgG by affinity chromatography.Results: The average particle size of 1%, 2% and 3% of CM were determined by optical microscopic method and particle size was found to be 30μm, 31μm, and 35μm respectively. Percentage of TT adsorbed in 1%, 2% and 3% CM were found to be 71%, 80% and 76% respectively by Limes flocculation method. In vitro studies showed that different batches (1%, 2% and 3%) of CM showed cumulative percentage release of TT 74.09%, 89.31%, and 80.23% respectively for 50 days. Among three batches of microspheres, 2% of chitosan microspheres showed better consistent and sustained release of TT for 50 days.Conclusions: This study suggested that 2% of chitosan microspheres could be useful for sustained release of tetanus toxoid to maintain the antibody titre for prolonged period. Keywords: Tetanus toxoid, Chitosan microspheres, Single shot vaccine.