Chitosan microspheres prepared by spray drying

Non-crosslinked and crosslinked chitosan microspheres were prepared by a sp ray drying method. The microspheres so prepared had a good sphericity and a smooth but distorted surface morphology. They were positively charged. The particle size ranged from 2 to 10 mu m. The size and seta potential of the particles were influenced by the crosslinking level. With decreasing amoun t of crosslinking agent (either glutaraldehyde or formaldehyde), both parti cle size and zeta potential were increased. Preparation conditions also had some influence on the particle size. DSC studies revealed that the H2 anta gonist drug cimetidine, as well as famotidine was molecularly dispersed ins ide the microspheres, in the form of a solid solution. The release of model drugs (cimetidine, famotidine and nizatidine) from these microspheres was fast, and accompanied by a burst effect. (C) 1999 Published by Elsevier Sci ence B.V. All rights reserved.