Gender Chitosan / Quaternary Ammonium Chitosan Complex Hydrogel On Bsa Release Behavior,

A class of biodegradable complex system based on chitosan was synthesized in order to develop a pH-responsive cartier for controlled release of protein.N-Carboxyethyl chitosan(CEC) and quaternized chitosan(HTCC) were synthesized by reaction of chitosan with acrylic acid and N-[(2-hydroxy-3-trimethylammonium)propyl] (GTMAC),respectively.Turbidimetric titration was employed to determine the stoichiometric ratio.A novel hydrogel composed of these two chitosan derivatives was prepared by the redox polymerization technique.The hydrogel was characterized by FT-IR,thermal gravimetric analysis(TGA),X-ray diffractometry(XRD) and scanning electron microscopy(SEM).The swelling ratio of CHC hydrogel depended significantly on the pH of the buffer solution.The performance of the CHC as matrix for controlled release of BSA was investigated.It was found that stoichiometric ratio between methacrylamide CEC and methacrylamide HTCC was 6.7:5.0. The hydrogel showed different swelling ratio in different pH values;the release behavior of BSA was determined by swelling ratio of the hydrogel as well as the intermolecular interaction between BSA and the hydrogels.Furthermore,N-Carboxyethyl chitosan(CEC),with various isoelectric points was synthesized by reaction of acrylic acid with chitosan.High degree of substitution of acrylic acid resulted in a lower stoichiometric ratio with HTCC.By turbidimetric trtration study,it was found that,CEC and HTCC can form complex within a certain pH range and the critical pH value for complexation(pH_Φ),the higher the DS,the lower the pH_Φ.Microgels based on CEC and HTCC were prepared by the photopolymerization technique according to seventy percent of the stoichiometric ratio.The pH-sensitivity and the zeta potential were investigated.The results showed that the microgels possess a high pH-sensitivity,the diameter of the microgels changed very sharply when the pH value lower the pH_Φ,which is almost the same as the pH-titration;the result also revealed that the lower the pH value,the higher the zeta potential.