Interfacial Adsorption of a Monoclonal Antibody and Its Fab and Fc Fragments at the Oil/Water Interface

• Published in: Langmuir 2019-10, Vol.35 (42), p.13543-13552
• Main Authors: Ruane, Sean, Li, Zongyi, Campana, Mario, Hu, Xuzhi, Gong, Haoning, Webster, John R. P, Uddin, Faisal, Kalonia, Cavan, Bishop, Steven M, van der Walle, Christopher F, Lu, Jian R
• Format: Article
• Language: English
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.9b02317

The physical stability of a monoclonal antibody (mAb) solution for injection in a prefilled syringe may in part depend on its behavior at the silicone oil/water interface. Here, the adsorption of a mAb (termed COE-3) and its fragment antigen-binding (Fab) and crystallizable (Fc) at the oil/water interface was measured using neutron reflection. A 1.4 ± 0.1 μm hexadecane oil film was formed on a sapphire block by a spin–freeze–thaw process, retaining its integrity upon contact with the protein solutions. Measurements revealed that adsorbed COE-3 and its Fab and Fc fragments retained their globular structure, forming layers that did not penetrate substantially into the oil phase. COE-3 and Fc were found to adsorb flat-on to the interface, with denser 45 and 42 Å inner layers, respectively, in contact with the oil and a more diffuse 17–21 Å outer layer caused by fragments adsorbing in a tilted manner. In contrast, Fab fragments formed a uniform 60 Å monolayer. Monolayers were formed under all conditions studied (10–200 ppm, using three isotopic contrasts), although changes in packing density across the COE-3 and Fc layers were observed. COE-3 had a higher affinity to the interface than either of its constituent fragments, while Fab had a lower interfacial affinity consistent with its higher net surface charge. This study extends the application of high-resolution neutron reflection measurements to the study of protein adsorption at the oil/water interface using an experimental setup mimicking the protein drug product in a siliconized prefilled syringe.