New non-chromatographic affinity matrices for antibody purification

抗体是制药行业中增长最快的部分。随着产品滴度的不断提高，生产过程也在不断优化，后续净化过程面临的挑战也越来越大，这可能占到总成本的80%。由于技术限制，色谱柱的体积不能扩大。色谱介质的高容量和过程稳定性变得越来越重要。在经典的基于蛋白A亲和层析的平台过程中，这两个参数都达到了极限：必须找到新的替代品。由于抗体通过亲和配体一步纯化，纯度高达95%，产率高，没有亲和配体的新工艺是不可能成功的。基于先前无与伦比的亲和配体，通过选择非色谱基质结合新的高容量碱基稳定的蛋白质配体，可以解决限制参数的挑战。通过对无孔基质和经典色谱介质的比较，可以看出中孔不仅对传质限制有负面影响，而且对抗体的洗脱条件和聚集行为也有负面影响。由于其简单的可加工性，载体材料的选择落在两种不同类型的不同尺寸的生物相容性磁性颗粒（微/纳米）上。根据大小的不同，它们具有相同甚至两倍的比表面积，每个载体单位结合更多抗体分子的潜力，并为蛋白质纯化设定了新的基准。此外，磁性纳米颗粒比微粒和色谱介质更便宜，更容易生产。

Antibodies form part of the most growing segment of pharmaceutical industry. Based on optimized production processes with increasing product titers the challenge for the subsequent purification process is also growing, which can account for up to 80% of the total costs. By technical limitations, the volumes of chromatography columns cannot be extended. Higher capacity and better process stability of the chromatographic media are becoming increasingly important. At the platform process with classical Protein A based affinity chromatography both parameters reached their limits: New alternatives have to be found. Since the antibodies are purified by affinity ligand in just one step with > 95 % purity and high yield, no new process could prevail without affinity ligands.Based on the previously unrivaled affinity ligands the challenge of limiting parameters will be solved by choosing a non-chromatographic matrix in combination of new high-capacity base-stabilized protein A-based ligands.By comparison of nonporous matrices and classical chromatographic media it will be shown that mesopores have not only a negative impact on mass transfer limitation but also on the elution conditions and aggregation behavior of antibodies. Because of their simple processability the choice of carrier materials falls on two different types of biocompatible magnetic particles of different size (micro / nano). Depending on the size, they have as much or even double specific surface area with the potential to bind more antibody molecules per carrier unit and to set a new benchmark in protein purification. Additional, magnetic nanoparticles are cheaper and simpler to produce than microparticles and chromatographic media.