Stability of a high-concentration monoclonal antibody solution produced by liquid-liquid phase separation

Jack Bramham, Stephanie A Davies, Adrian Podmore, Alexander Golovanov

Research output: Contribution to journalArticlepeer-review


Subcutaneous injection of a low volume (<2 mL) high concentration (>100 mg/mL) formulation is an attractive administration strategy for monoclonal antibodies (mAbs) and other biopharmaceutical proteins. Using concentrated solutions may be also beneficial at various stages of bioprocessing. However, concentrating proteins by conventional techniques, such as ultrafiltration, can be time consuming and challenging. Isolation of the dense fraction produced by macroscopic liquid-liquid phase separation (LLPS) has been suggested as a means to produce high-concentration solutions, but questions arise regarding the practicality of this method, and the stability of the resulting protein solution. In this proof-of-concept study, we demonstrate that LLPS can be used to concentrate a mAb solution to >170 mg/mL. We show that the structure of the mAb is not altered by LLPS, and unperturbed mAb is recoverable following dilution of the dense fraction, as judged by 1H nuclear magnetic resonance (NMR) spectroscopy. Finally, we show that the physical properties and stability of a model high concentration protein formulation obtained from the dense fraction can be improved, for example through the addition of the excipient arginine·glutamate. This results in a stable high-concentration protein formulation with reduced viscosity and no further macroscopic LLPS. Concentrating mAb solutions by LLPS represents a simple and effective technique to progress towards producing high-concentration protein formulations for bioprocessing or administration.
Original languageEnglish
Publication statusAccepted/In press - 7 Jun 2021


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