Fabrication and Characterization of Antibody-Loaded Cationic Porous PLGA Microparticles for Sustained Antibody Release.

Poly lactic-co-glycolic acid (PLGA) microparticles have been formulated to allow the sustained release of numerous drugs, including antibodies. It is well-known that antibodies are susceptible to chemical and physical stress; therefore, it is necessary to be loaded on PLGA microparticles under mild conditions. In the present study, we constructed cationic porous PLGA microparticles that could be electrostatically adsorbed with infliximab as a model antibody. Cationic porous PLGA microparticles were prepared using the double emulsion method by adding polyethyleneimine and ammonium bicarbonate. After antibody loading, surface pores closure was achieved by mild heating. The size of the optimized formulation was approximately 5 μm, exhibiting a positive charge. The loaded antibody was gradually released from the formulation over 56 days. Based on a tumor necrosis factor (TNF)-α inhibition assay, the released infliximab maintained its pharmacological activity. Collectively, we successfully loaded antibodies into PLGA microparticles while maintaining activity and demonstrating long-acting properties.