Comparison and process optimization of PLGA, chitosan and silica nanoparticles for potential oral vaccine delivery.

The study compared performance of nanoparticles prepared from synthetic organic, natural organic and inorganic materials as vaccine delivery platforms. Various formulation (concentration, polymer/silica:surfactant ratio, solvent) and process parameters (homogenization speed and time, ultrasonication) affecting functional performance characteristics of poly(lactic--glycolic acid) (PLGA), chitosan and silica-based nanoparticles containing bovine serum albumin were investigated. Nanoparticles were characterized using dynamic light scattering, x-ray diffraction, scanning/transmission electron microscopy, Fourier transform infrared spectroscopy and protein release. Critical formulation parameters were surfactant concentration (PLGA, silica) and polymer concentration (chitosan). Optimized nanoparticles were spherical in shape with narrow size distribution and size ranges of 100-300 nm (blank) and 150-400 nm (protein loaded). Protein encapsulation efficiency was 26-75% and released within 48 h in a sustained manner. Critical formulation and process parameters affected size of PLGA, chitosan and silica nanoparticles and protein encapsulation, while silica produced the smallest and most stable nanoparticles.