Abstract
In this paper, the release and the permeation characteristics of model drugs of crosslinked porous silk fibroin gel (CPFG) and its solubility and degradability were investigated. CPFG was prepared by using ethylene glycol diglycidyl ether (EGDE) as a crosslinking agent. It was found that with an increase of pH of the bulk solution, the release rate of the a cationic compound from CPFG was lowered and that of an anionic one was quickened. However, the release rate of the non-ionic compound was independent witk pH of the solution. These release rates of the charged drugs were changed by modifying -COOH residues of fibroin. The permeation diffusion rate of the compounds in CPFG decreased with the decrease of pore size (the increase of the density) of CPFG. Moreover, The diffusion rate was also affected by an electrostatic interaction between compounds and CPFG. In neutral or weakly acidic solution, a small amount of fibroin was dissolved from CPFG, and the amount of dissolved fibroin increased in acidic or alkaline solution. CPFG can also be degraded by protease.
