Nano-in-microparticles for dry powder vaccination – possible for nasal application?
Department of Pharmaceutics and Biopharmaceutics, Kiel University, Grasweg 9a, 24118 Kiel, Germany
Nanoparticles have been identified as very promising carrier as well as adjuvant system in nasal vaccination. A material widely used for this purpose is chitosan which is characterised by its molecular weight and degree of deacetylation. In this study nanoparticles are formed with different chitosan qualities and a low viscosity carboxymethylcellulose sodium salt (approx. 90 kDa) in different ratios via ionic gelation. It could be shown that protein encapsulation is dependent on the chitosan quality depicting higher encapsulation efficiencies for higher deacetylated qualities. Furthermore, a higher amount of carboxymethylcellulose in the particles resulted in higher protein encapsulation. Nanoparticles are embedded in a microparticle matrix via spray drying to allow nasal dry powder administration and mannitol was chosen as excipient for the matrix. Utilising an ultrasonic nozzle particle sizes above 10 µm which are suitable for nasal deposition could be obtained. These were well dispersible by means of a nasal dry powder device.