The effect of chitosan molecular weight on the properties of alginate/ chitosan microparticles containing prednisolone

Purpose: The aim of the present study was to investigate the effect of chitosan molecular weight on size, size distribution, release rate, mucoadhesive properties and electrostatic bonding of alginate/chitosan microparticles containing prednisolone Methods: Three mucoadhesive alginate/chitosan microparticle formulations, f1, f2 and f3, were prepared using low, medium and high chitosan molecular weight (MW) chitosan, respectively, by directly spraying alginate solution into a solution of chitosan and calcium chloride at optimum conditions. Prednisolone was incorporated in the alginate solution prior to spraying. The microparticles were then evaluated for prednisolone content, size, release rate, and mucoadhesive properties using appropriate methods. The formation of electrostatic and hydrogen bonds between chitosan and alginate was assessed by differential scanning calorimetetry (DSC) and Fourier transform infrared (FTIR). Results: The results indicate that high MW chitosan microparticles were significantly (p<0.05) smaller and more uniform in size, with better mucoadhesive properties and lower release rate than the other formulations. FTIR and DSC studies indicate that stronger hydrogen and electrostatic bonding in the formulation containing high MW chitosan than inthe other formulations Conclusion: The physicochemical properties of chitosan-alginate microparticles are dependent on the molecular weight of chitosan