Abstract

BIODEGRADABLE CHITOSAN-BASED MICROSPHERES FOR CONTROLLED ORAL VACCINE DELIVERY: SYNTHESIS, CHARACTERIZATION, AND RELEASE KINETICS

Vaishali S. Raundal* and Vasant B. Kadam

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Abstract

In recent years, advances in biodegradable polymer-based drug delivery systems have opened new avenues for oral vaccine administration. Chitosan, a natural cationic polysaccharide, has attracted considerable interest due to its mucoadhesive properties, biocompatibility, and ability to enhance mucosal permeability. In this study, caprylate–chitosan/alginate–cetyl trimethyl ammonium bromide (CTAB) polyelectrolyte complexes were synthesized for the encapsulation of diphtheria and tetanus toxoids. The microparticles were prepared via coacervation and characterized using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). Entrapment efficiency, loading capacity, swelling index, and in-vitro release kinetics were evaluated. The microspheres exhibited high entrapment efficiency (TT: 91.12%, DT: 87.26%) and sustained release profiles over three weeks, following anomalous diffusion kinetics. SEM revealed smooth, sponge-like particles with low sphericity, while FT-IR confirmed polyelectrolyte complex formation. These findings highlight the potential of chitosan-based microspheres as an effective oral vaccine delivery platform, enabling controlled antigen release and enhanced mucosal immunization.

Keywords: Chitosan, Controlled release, Oral vaccine delivery, Microspheres, Biodegradable polymers, Mucoadhesion, Diphtheria toxoid, Tetanus toxoid.