喷雾干燥法制备微胶囊方法.pdf

Journal of Microencapsulation , June 2005; 22(4): 377–395 Preparation of cross-linked chitosan microspheres by spray drying: Effect of cross-linking agent on the properties of spray dried microspheres K. G. H. DESAI1 H. J. PARK1,2 1School of Life Sciences and Biotechnology, Korea University, Sungbuk-ku, Seoul, South Korea, and 2School of Life Sciences and Biotechnology, Korea University and Department of Packaging Science, Clemson University, Clemson, SC, USA (Received 4 September 2004; accepted 10 December 2004) Abstract Chitosan microspheres cross-linked with three different cross-linking agents viz, tripolyphosphate (TPP), formaldehyde (FA) and gluteraldehyde (GA) have been prepared by spray drying technique. The influence of these cross-linking agents on the properties of spray dried chitosan microspheres was extensively investigated. The particle size and encapsulation efficiencies of thus prepared chitosan microspheres ranged mainly between 4.1–4.7 mm and 95.12–99.17%, respectively. Surface morphol- ogy, % erosion, % water uptake and drug release properties of the spray dried chitosan micro- spheres was remarkably influenced by the type (chemical or ionic) and extent (1 or 2% w/w) of cross-linking agents. Spray dried chitosan microspheres cross-linked with TPP exhibited higher swelling capacity, % water uptake, % erosion and drug release rate at both the cross-linking extent (1 and 2% w/w) when compared to those cross-linked with FA and GA. The sphericity and surface smoothness of the spray dried chitosan microspheres was lost when the cross-linking extent was increased from 1 to 2% w/w. Release rate of the drug from spray dried chitosan microspheres decreased when the cross-linking extent was increased from 1 to 2% w/w. The physical state of the drug in chi