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

Plasticizers are usually added to improve the mechanical and conditional (thermomechanical) quality of film coatings. Different molecular weights and concentrations of polyethylene glycol were incorporated as plasticizers in hydroxypropylmethylcellulose (HPMC) films. Thermomechanical and mechanical properties of cast films were tested using tensile and dynamic mechanical thermal analysis (DMTA) testing, respectively. The results, as expected, showed that addition of plasticizer caused a decrease in both mechanical and thermomechanical properties, but lower grades had more effect than higher molecular weights and concentrations. The conclusion could be drawn that combining different grades of plasticizers to optimize mechanical and thermomechanical properties is more efficient than using different concentrations of plasticizers.