This study reports, for the first time, an aqueous high-concentration antibody formulation reaching up to 360 mg/mL. By combining solvent dehydration with microfluidic technology, the method simultaneously achieves antibody precipitation and encapsulation into hydrogel microspheres, significantly enhancing formulation stability and injectability.
Literature Overview
The article titled 'High-Concentration Antibody Formulation via Solvent-Based Dehydration,' published in the journal Advanced Materials (Deerfield Beach, Fla.), reviews and summarizes a novel solvent-dehydration-based approach for preparing high-concentration antibody formulations. This method employs microfluidic emulsification to introduce aqueous droplets containing antibody and polyethylene glycol (PEG) into a pentanol organic phase, enabling rapid water extraction. This process simultaneously induces the formation of amorphous solid dispersions (ASD) of the antibody and triggers cross-linking of alginate into hydrogel microspheres via calcium ions, resulting in efficient antibody encapsulation. The final microspheres can be stably suspended in an aqueous phase containing PEG, achieving formulation concentrations as high as 360 mg/mL, with excellent injectability and long-term stability. The study systematically analyzes antibody phase behavior, dehydration kinetics, and microsphere formation, and confirms the structural integrity, bioactivity, and rapid release characteristics of the formulation. This technology overcomes the viscosity and stability limitations of conventional high-concentration antibody solutions, offering an ideal aqueous formulation platform for subcutaneous delivery.Background Knowledge
Monoclonal antibodies (mAbs), as important biotherapeutic agents, are widely used in the treatment of diseases such as cancer and autoimmune disorders. Although traditional intravenous infusions are effective, their high cost and requirement for administration by medical professionals limit patient compliance. Subcutaneous (SC) injection, by contrast, offers advantages such as convenience, low cost, and potential for self-administration, making it a more desirable delivery route. However, subcutaneous injection is limited by small injection volumes (typically <2 mL), necessitating antibody concentrations far exceeding 200 mg/mL to deliver therapeutic doses. Conventional high-concentration antibody solutions often suffer from high viscosity, aggregation, and physical instability, leading to injection difficulties and increased immunogenicity risks. Existing solutions, such as non-aqueous formulations or lyophilized powders requiring reconstitution, can increase concentration but often cause injection-site pain and inflammation, with limited post-reconstitution concentration. Solid forms such as crystals or amorphous protein particles offer good stability but struggle to achieve high-concentration aqueous suspensions. Previous attempts to encapsulate precipitated antibody particles in hydrogel microspheres have relied on centrifugation, making continuous production difficult, and resulted in large particle sizes (>100 μm), limiting practical application. Therefore, developing a scalable, aqueous-stable, high-concentration, and easily injectable antibody formulation platform remains a key challenge in the field of biopharmaceutical formulation. This study addresses the contradiction between high concentration and aqueous stability by integrating solvent dehydration with microfluidic technology, enabling in situ formation of antibody ASD and simultaneous hydrogel encapsulation, thus offering a novel strategy for subcutaneous delivery.
Research Methods and Experiments
The researchers first constructed a phase diagram of human IgG and PEG to determine the conditions for forming amorphous solid dispersions (ASD). Using single-particle dehydration experiments, they observed droplet size changes in pentanol via optical microscopy and analyzed dehydration kinetics using the Epstein–Plesset model, confirming that PEG effectively induces rapid ASD formation during dehydration. Subsequently, alginate and calcium ions were introduced to enable simultaneous encapsulation of ASD into hydrogel microspheres. A microfluidic flow-focusing device enabled continuous production, with microsphere size precisely controlled (down to <100 μm) by adjusting the flow rate ratio between the continuous and dispersed phases. The resulting microspheres were systematically characterized for drug loading, encapsulation efficiency, injection force, secondary structure (CD and FTIR), bioactivity (ELISA), and in vitro release behavior.Key Conclusions and Perspectives
Research Significance and Prospects
This study presents an innovative aqueous formulation platform for high-concentration antibodies, resolving the conflict between high concentration and low viscosity/stability in subcutaneous delivery. By driving ASD formation and hydrogel encapsulation through solvent dehydration, the method enables efficient antibody concentration and physical protection while preserving the biocompatibility advantages of aqueous delivery. The integration of microfluidic technology ensures scalability and controllable particle size, making it suitable for industrial production. This platform is not only applicable to IgG-class antibodies but could theoretically be extended to other therapeutic proteins, peptides, or nucleic acid drugs, provided their solid forms can be stabilized.
Future research could further explore the regulation of microsphere rheology and release kinetics using different polymers and cross-linking systems to optimize formulation performance. In addition, in vivo pharmacokinetic and immunogenicity studies are needed to validate its clinical translatability. This technology has the potential to advance the development of subcutaneous delivery for various high-dose biologics, improving patient compliance and treatment accessibility, and holds broad clinical application prospects.
Conclusion
This study successfully developed a novel method for high-concentration aqueous antibody formulation based on solvent dehydration, using microfluidic technology to enable in situ formation of antibody amorphous solid dispersions and simultaneous encapsulation into hydrogel microspheres. The method overcomes the viscosity and stability limitations of traditional high-concentration antibody solutions, achieving a final formulation concentration of up to 360 mg/mL as an aqueous suspension—significantly outperforming non-aqueous formulations. The microspheres exhibit excellent injectability (injection force <20 N), long-term stability (4 months), and rapid in vitro release, meeting key requirements for subcutaneous delivery. The platform is continuous, scalable, and allows tunable particle size, making it suitable for various therapeutic proteins. This work not only provides an innovative solution for high-concentration antibody formulations but also opens new avenues for convenient and long-acting delivery of other biomacromolecules, demonstrating significant scientific value and translational potential. Future efforts should focus on validating its in vivo performance and safety to advance toward clinical application.
