Preparation and characterization of hydrogel from chitin derivative and silk fibroin

Abstract

Natural polymer blend films composed of chitosan and silk fibroin were prepared by solution casting technique with various ratios of chitosan to silk fibroin, using glutaraldehyde as crosslinking agent. The effects of the ratio of chitosan to silk fibroin and crosslinking agent on mechanical properties, swelling behavior and drug releasing property of the blend films were studied. For the swelling behavior, the blend films exhibited a dramatic change in the degree of swelling when immersed in acidic solutions. The blend film with 80% chitosan content had the maximum degree of swelling. It appeared that crosslinking occurred in the blend films helped the films retain their three dimensional structure. In addition, FTIR spectra of the films showed evidence of hydrogen bonding interaction between chitosan and silk fibroin. Drug release characteristics of the blend films with various blend compositions were investigated using theophylline, diclofenac sodium, amoxicillin trihydrate and salicylic acid as model drugs. It was found that the blend film with 80% chitosan content showed the maximum amount of drug release at pH 2.0 for all types of drugs. The maximum amount of salicylic acid, theophylline, diclogenac sodium and amoxicillin release from blend films with 80% chitosan content at pH 2.0 were 92.7%, 81.1%, 76.6%, and 37.2%, respectively. Drug release properties of the films with various blend compositions were also investigated using a modified Franz Diffusion cell and pig skin was used as material representing human skin.