McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas78712, United States.
Analytical Enabling Capabilities, Analytical R&D, Merck & Co., Inc., Rahway, New Jersey07065, United States.
J Phys Chem B. 2023 Feb 9;127(5):1120-1137. doi: 10.1021/acs.jpcb.2c07616. Epub 2023 Jan 30.
Attractive protein-protein interactions in concentrated monoclonal antibody (mAb) solutions may lead to the formation of clusters that increase viscosity. Here, we propose an analytical model that relates mAb solution viscosity to clustering by accounting for the contributions of suboptimal mAb packing within a cluster and cluster fractal dimension. The influence of short-range, anisotropic attractions and long-range Coulombic repulsion on cluster properties is investigated by analyzing the cluster-size distributions, cluster fractal dimensions, radial distribution functions, and static structure factors from a library of coarse-grained molecular dynamics simulations. The library spans a vast range of mAb charges and attractive interactions in solutions of varying ionic strength. We present a framework for combining the viscosity model and simulation library to successfully characterize the attraction, repulsion, and clustering of an experimental mAb in three different pH and cosolute conditions by fitting the measured viscosity or structure factor from small-angle X-ray scattering. At low ionic strength, the cluster-size distribution is impacted by strong charges, and both the viscosity and net charge or structure factor and net charge must be considered to deconvolute the effects of short-range attraction and long-range repulsion.
在高浓度单克隆抗体 (mAb) 溶液中，有吸引力的蛋白-蛋白相互作用可能导致聚集体的形成，从而增加溶液的黏度。在这里，我们提出了一个分析模型，该模型通过考虑聚集体内部次优 mAb 堆积和聚集体分形维数的贡献，将 mAb 溶液黏度与聚集联系起来。通过分析来自粗粒分子动力学模拟库的簇大小分布、簇分形维数、径向分布函数和静态结构因子，研究了短程各向异性吸引力和长程库仑排斥力对簇性质的影响。该库涵盖了 mAb 电荷和溶液离子强度变化时的各种吸引力。我们提出了一个框架，将黏度模型和模拟库结合起来，通过拟合小角度 X 射线散射测量的黏度或结构因子，成功地描述了三种不同 pH 值和共溶剂条件下实验 mAb 的吸引力、排斥力和聚集作用。在低离子强度下，簇大小分布受到强电荷的影响，为了解卷积短程吸引力和长程排斥力的影响，必须同时考虑黏度和总电荷或结构因子和总电荷。
