Caffeine as a Viscosity-Reducing Agent for High-Concentration mAb Formulations: Insights from Molecular Dynamics...

Area of Science:

• Biochemistry
• Pharmaceutical Sciences
• Computational Biology

Background:

• High-concentration monoclonal antibody (mAb) formulations are preferred for subcutaneous delivery but face viscosity challenges.
• Caffeine is a potential viscosity-reducing agent for mAbs, but its molecular mechanism is not fully understood.

Purpose of the Study:

• To elucidate the molecular interactions between caffeine and ipilimumab using all-atom molecular dynamics (MD) simulations.
• To understand how caffeine affects mAb conformation and self-association.

Main Methods:

• All-atom molecular dynamics (MD) simulations were performed to model caffeine-ipilimumab interactions.
• Trajectory analysis identified key caffeine-contact residues on the antibody.
• K-means clustering was used for conformational analysis of antibody fragments.

Main Results:

• Hydrophobic effects, not electrostatic interactions, drive caffeine binding to ipilimumab.
• Caffeine preferentially interacts with specific residues, including TRP101, which are involved in Fab-Fab interactions.
• Caffeine binding leads to more rigid Fab and Fc conformations without altering overall mAb compactness.

Conclusions:

• Caffeine may reduce mAb formulation viscosity by shielding self-association 'hot spots', weakening reversible self-association.
• These findings provide a molecular basis for using caffeine as a viscosity-reducing agent in high-concentration mAb formulations.