Investigation of modified chitosan synthesis and drug delivery properties

Amphiphilic compound salicylaldehydediol (SAD) as a linker group to the chitosan backbone was synthesized from nucleophilic reactive salicylaldehyde and hydrophilic reactive 2,3-epoxy-1-propanol (glycidol) by epoxide ring opening reaction in high yield and regioselectivity. Three modified chitosan biopolymer have been synthesized by covalently bonding of dynamic imination reaction with varying concentrations of SAD as a linker group to the chitosan. Modified chitosan biopolymers transformed as hydrogel (CSADJ1-3) and films (CSADF1-3) forms. Structur of biopolymers were evaluated by Fourier Transform Infrared (FT-IR) spectroscopy, Nuclear Magnetic Rezonans (NMR), Differential Scanning Calorymery (DSC), X-Ray Diffraction (XRD) data. This results clearly show that the SAD linked to the chitosan backbone. The data of Scaning Electron Microscopy of the fabricated hydrogels show the fabricated hydrogels had a porous structure and pore sizes reduced with increasing of SAD group ratio. In both acidic and alkaline medium, the SAD linking group created networks that were insoluble, but swelled in aqueous media. The highest swelling capacity of hydrogels was obtained at pH 7 with the order of CSADJ1, CSADJ2, and CSADJ3, respectively. The high thermal stability of modified chitosan was determined by thermal gravimetric analysis (TGA) and differential electron scanning (DSC). Ibuprofen was selected as a model drug, and the controlled releases of ibuprofen are influenced by the pore sizes of hydrogels. The reaction takes place with high conversation and amazingly mechanically resistant thickness films without using any plasticizer that exhibits low water solubility and low swelling ratios at pH > 3, which can be suggested as thin layer protecting systems for medical devices and food packaging. The concentrations of linker group effect different physicochemical features of the biopolymer, including thermal stability, shape, swelling, and water solubility. Considering the physicochemical properties of biopolymers, tissue engineering, wound healing reagent, drug carrier and release systems, surface coating material, etc. These new modified chitosan materials can be used in many biomedical fields.