Chitosan microparticles loaded with exotoxin A subunit antigen for intranasal vaccination against Pseudomonas aeruginosa: An in vitro study

Chitosan microparticles (CMs) were prepared with tripolyphosphate by spray-drying. Effects of polymer molecular weight, sonication power, cross-linking time and concentration of TPP on release profiles of catalytic or third domain pseudomonas exotoxin A (PEIII) and morphology of CMs were evaluated. The mean particle sizes of CMs were in the range from 1.09–1.46 μm and antigen loading efficiencies were more than 59%. As the molecular weight of chitosan increased, microparticles had a more spherical shape and a smooth surface. An increase in sonication power and decrease in cross-linking time resulted microparticles morphology changes.Approximately 60–80% of PEIII released from microparticles within the first few hours. The release of antigen is increased significantly by raising the sonication power more than 45 W. When the cross-linking time extended from 15 to 60 min, the release of PEIII significantly reduced. The release of PEIII from the microparticles increased when concentration of TPP was raised.