A pH-Responsive Molecularly Imprinted Hydrogel for Dexamethasone Release

A new type of pH-responsive molecularly imprinted polymer (MIP) hydrogel was reported, which can well control the release of dexamethasone sodium phosphate (DXP). The MIP hydrogel were prepared by precipitation polymerization using dopamine acrylamide (DPA) and acrylic acid (AAc) as functional monomers and DXP as the template molecule. The synthesized MIP hydrogel were characterized by SEM and FT-IR spectrometer. The rates of drug loading and drug release were determined by UV spectroscopy analysis. The results showed that the drug loading rate of MIP hydrogel was significantly higher than that of NIP hydrogel when immersed in different DXP solutions. Only 58% of the loaded drug released from MIP hydrogel in 24 h while the released drug exceed 80% for the NIP hydrogel, and such controlled slow release characteristics of MIP hydrogel sustained 7 days. Furthermore, the DXP-imprinted hydrogel exhibited pH-dependent due to the molecular interaction between the polymerized DPA and AAc.