Preparation of sericin microparticles by electrohydrodynamic spraying and their application in drug delivery

Sericin (SS) is a protein present in silkworm cocoons that is normally discarded in the degumming process. Recycling sericin can expand the library of natural polymers used in the materials field. In this study, sericin microparticles were prepared using an electrohydrodynamic (EHD) spraying technique. The sizes of the SS microparticles, which can be controlled by the concentration of the dope solution, flow rate and applied voltage, were in the range of 100-300 mu m. The swelling and dissolution of SS microparticles were suppressed at pH 2.2 and increased at pH 7.4, indicating their potential in oral drug delivery applications. Diclofenac was used as a model drug, and its release from SS microparticles was suppressed in the stomach-simulated fluid but was increased in the small intestine-simulated fluid.