A New Approach to Antivenom Preparation Using Chitosan Nanoparticles Containing Echis Carinatus Venom as A Novel Antigen Delivery System

In recent years, use of biodegradable polymers based nanoparticles has received highinterest in the development of vaccines delivery vehicles. The aim of study was to preparechitosan nanoparticles (CS NPs) for loading Echis carinatus (EC) venom and evaluate theirpotential as an adjuvant and antigen delivery system on a pilot scale. CS NPs were preparedusing ionic gelation method, and their characteristics were optimized. Venom-loaded CS NPsprepared under optimum conditions and traditional venom-loaded adjuvants were used tohyperimmunization of horse. Under optimum conditions, particle size, polydispersity index(PDI), and zeta potential of CS NPs were 127.9 ± 15 nm, 0.29, and +19.8 ± 1.92 mV, whilethose of venom-loaded CS NPs were 182.4 ± 20 nm, 0.35, +26.8 ± 1.98 mv, respectively. AllCS NPs had integrated surface and good morphology. Optimum loading concentration of ECvenom was 500 μg/mL. The loading capacity (LC) and loading efficiency (LE) were 87% and94%, respectively, and release profile of venom-loaded CS NPs showed suitable correlationwith Higuchi kinetics. Stability test showed good stability of the venom encapsulated in CSNPs. Furthermore, antivenom plasma obtained using the new antigen delivery system hadsignificantly higher potency (P < 0.05) for neutralizing the venom than that obtained usingconventional system. These results suggested that venom-loaded CS NPs could be a suitablealternative to conventional adjuvant for development antivenom.