Preparation of pH-sensitive Hydrogels for Oral Delivery of Protein

The pH-sensitive hydro gels of PEGMA grafted Poly (methacrylic acid) (P(PEGMA-g-MAA)) were synthesised through free radical solution polymerization. The influencing factors on the polymerization, such as monomer ratio, quantity of monomers, cross-linker concentration, and initiator concentration, were investigated. The FTIR measurements showed the P(PEGMA-g-MAA) hydro gels were synthesized. The swelling properties studies illustrated that these hydro gels had pH-sensitive behaviors. In the study, BSA, as a model protein, was loaded into the hydro gel particles through immersion method. In vitro release researches of BSA-loaded hydro gels were conducted in simulate gastrointestinal tract, and the results showed BSA release from hydro gel particles was less than 20% at acidic solution, whereas a more release was obtained at weak alkali solution. All these data indicated that the hydro gels of P(PEGMA-g-MAA) were prospective in application for proteins and peptides delivery.