Abstract

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 mu m 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. (C) 2010 Elsevier Ltd. All rights reserved.