Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado, USA.
J Pharm Sci. 2010 Jan;99(1):82-93. doi: 10.1002/jps.21797.
Opalescence and high viscosities can pose challenges for high concentration formulation of antibodies. Both phenomena result from protein-protein intermolecular interactions that can be modulated with solution ionic strength. We studied a therapeutic monoclonal antibody (mAb) that exhibits high viscosity in solutions at low ionic strength ( approximately 20 cP at 90 mg/mL and 23 degrees C) and significant opalescence at isotonic ionic strength (approximately 100 nephelometric turbidity units at 90 mg/mL and 23 degrees C). The intermolecular interactions responsible for these effects were characterized using membrane osmometry, static light scattering, and zeta potential measurements. The net protein-protein interactions were repulsive at low ionic strength ( approximately 4 mM) and attractive at isotonic ionic strengths. The high viscosities are attributed to electroviscous forces at low ionic strength and the significant opalescence at isotonic ionic strength is correlated with attractive antibody interactions. Furthermore, there appears to be a connection to critical phenomena and it is suggested that the extent of opalescence is dependent on the proximity to the critical point. We demonstrate that by balancing the repulsive and attractive forces via intermediate ionic strengths and by increasing the mAb concentration above the apparent critical concentration both opalescence and viscosity can be simultaneously minimized.
对于高浓度的抗体制剂来说，乳光和高黏度可能会带来挑战。这两种现象都源于蛋白质-蛋白质分子间的相互作用，可以通过溶液离子强度来调节。我们研究了一种治疗性单克隆抗体（mAb），该抗体在低离子强度的溶液中（90mg/ml 和 23°C 时约为 20cP）表现出高黏度，在等渗离子强度下（90mg/ml 和 23°C 时约为 100 奈光浊度单位）表现出显著的乳光。使用膜渗透压计、静态光散射和zeta 电位测量来表征这些效应的分子间相互作用。在低离子强度（约 4mM）下，净蛋白-蛋白相互作用是排斥的，而在等渗离子强度下是吸引的。低离子强度下的高黏度归因于电动黏度力，等渗离子强度下的显著乳光与抗体的吸引力相互作用有关。此外，似乎与临界现象有关，并且表明乳光的程度取决于接近临界点的程度。我们证明，通过在中间离子强度下平衡排斥力和吸引力，以及通过将 mAb 浓度提高到表观临界浓度以上，可以同时最小化乳光和黏度。
