Chitosan-gelatin sponges for controlled drug delivery: the use of ionic and non-ionic plasticizers

The influence of ionic and non-ionic plasticizers on the mechanical propert ies and drug dissolution rates of chitosan-gelatin sponges was investigated . Mannitol and sodium chloride, as model plasticizers, and chitosan with tw o different viscosity grades, were examined Furthermore, drug release was c ontrolled by glutaraldehyde cross-linking. It was found that the mechanism of plasticization depended on the structure of the plasticizer. Release of the model drug prednisolone depended on the degree of cross-linking, the vi scosity grade of chitosan and the type of plasticizer Both the plasticizers examined facilitated the foaming up of polymer solutions and softened the sponges produced,vith low viscosity chitosan. Moreover, only sodium chlorid e significantly reduced the apparent density of the sponges. Those prepared with high density chitosan were not plasticized by either mannitol or sodi um chloride.