Protein Loading into Spongelike PLGA Microspheres

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.

Template-Based Porous Hydrogel Microparticles as Carriers for Therapeutic Proteins

Hydrogels have been extensively researched for over 60 years for their limitless applications in biomedical research. In this study, porous hydrogel microparticles (PHMPs) made of poly(ethylene glycol) diacrylamide were investigated for their potential as a delivery platform for therapeutic proteins. These particles are made using hard calcium carbonate (CaCO₃) templates, which can easily be dissolved under acidic conditions. After optimization of the synthesis processes, both CaCO₃ templates and PHMPs were characterized using a wide range of techniques. Then, using an array of proteins with different physicochemical properties, the encapsulation efficiency of proteins in PHMPs was evaluated under different conditions. Strategies to enhance protein encapsulation via modulation of particle surface charge to increase electrostatic interactions and conjugation using EDC/NHS chemistry were also investigated. Conjugation of bovine serum albumin to PHMPs showed increased encapsulation and diminished release over time, highlighting the potential of PHMPs as a versatile delivery platform for therapeutic proteins such as enzymes or antibodies.

Self-Boosting Vaccination Based on Pulsatile Antigen Release from Core-Shell Microparticles

Vaccination is among the most effective ways to prevent infectious diseases. Subunit vaccines are safe but usually require multiple booster shots, which may lead to immunity loss and economic consume. In this study, a self-boosting vaccine is developed based on the pulsatile release of antigen from the core-shell microparticle after single-injection immunization. Self-healing technology applied to form an "antigen core" can avoid organic solvents from destroying the spatial structure of the antigen. The "antigen shell" is built-up by self-assemble of the antigen with the opposite charged polypeptide. Primary immunization occurs with the self-assembled film disintegration, and the booster comes with the microparticle degradation. The changing of antigen-specific antibodies after immunization with the core-shell microparticle vaccine is consistent with that caused by the two shots of immunization. The immune effect and safety evaluation results support the translational potential of this self-boosting core-shell microparticle vaccine.

Bridging the gap between fundamental research and product development of long acting injectable PLGA microspheres

INTRODUCTION

Long acting Injectable PLGA microspheres have gained more and more interest and attention in the field of life cycle management of pharmaceutical products due to their biocompatibility and biodegradability. So far, a multitude of trial-and-error experiments at lab scale have been used for establishing the correlation relationship between critical process parameters, critical material attributes and critical quality attributes. However, few published studies have elaborated on the development of PLGA microspheres from an industrial perspective.

AREAS COVERED

In this review, the scale-up feasibility of translational technologies of PLGA microspheres manufacturing have been evaluated. Additionally, state-of-the-art of technologies and facilities in PLGA development have been summarized. Meanwhile, the industrial knowledge matrix of PLGA microspheres development and research are establishing which provide comprehensive insight for understanding properties of PLGA microspheres as controlled/sustained release vehicle.

EXPERT OPINION

There is still big gap between fundamental research in academic institute and product development in pharmaceuticals. Therefore, the difference and connection between them should be identified gradually for better understanding of PLGA microspheres development.

Controllable preparation of bioactive open porous microspheres for tissue engineering

Biodegradable microspheres have been widely applied as cell carriers for tissue engineering and regenerative medicine. However, most cell carriers only have simple planar structure and show poor biological activity and...