Antibodies are a unique class of proteins, which play a central role in the immune system. While the antibody scaffold structure remains fairly consistent, the antigen binding regions exhibit incredible variability, allowing the immune system to produce antibodies to recognise an almost limitless number of target antigens.
With a combination of antigen binding and immunomodulation, antibodies are a crucial component of the immune response against pathogenic micro-organisms. It is the ability to bind to target epitopes with incredible specificity that has resulted in antibodies becoming a major class of therapeutic proteins.
The development of therapeutic antibodies focuses on identification and purification of the antibody clone with the appropriate target recognition and binding affinity. This involves screening of many antibodies for these particular attributes, and so high throughput screening of binding affinities is of great value during the development of such products.
Understanding the colloidal stability of antibodies allows prediction of antibody stability, thereby increasing the efficiency of the formulation development phase.
Antibodies can now be manufactured at high concentrations, allowing the development of high concentration, low dose injectables. Due to the challenges associated with high concentration formulations, the ability to screen solution viscosity early during formulation development, with low sample volumes and high sample number, can be very beneficial.
A major risk factor for antibody instability and degradation is the loss of native structure. Consequently, antibody structure characterization, coupled to the detection of aggregates, allows identification of subtle changes in secondary and tertiary structures thereby providing detailed knowledge of antibody stability.
For all Biopharmaceutical parenterals, immunogenicity is of major concern. Therefore, it is important for aggregated species, including soluble aggregates and subvisible particles to be fully characterized. Understanding the progression and characteristics of these degradation pathways is an important aspect of product knowledge that can aid drug development and facilitate problem solving. This requires characterizing antibody structural attributes in response to various stresses.
With the development of high concentration, low dose, therapeutic antibodies, the use of pre-filled syringes is a growing trend. However, the presence of silicone oil droplets can impact particle characterization, while also promoting aggregate formation. Therefore, it is important to evaluate of potential impact of these and other contaminants, on the active component and the patient.
Our solutions can be applied to many of the problems associated with the development and commercialization of therapeutic antibodies.
We can characterise antibodies from monomers up to 10µm subvisible particles:
- The determination of % aggregation and molecular weight of aggregates by TDA and SEC-MALS;
- Antibody size distribution from 0.3 nm to 10 µm by Zetasizer Nano;
- Particle size and number distributions from 10 nm to 5 µm by Nanoparticle Tracking Analysis (NTA) and Archimedes;
- Provide real time antibody size distribution data for Bioprocessing monitoring as a PAT tool.
- Our resonant mass determination, using Archimedes, enables distinction between protein and non-protein particles.
We have a range of High-throughput Screening tools to support early stage formulation development:
- Antibody size distributions can be obtained on both 96/384-well plates using Zetasizer APS;
- Antibody monomer size and formulation viscosity can be determined using Viscosizer TD;
- Antibody-epitope interactions can be measured, characterised and screened using our Auto iTC200 isothermal titration calorimetry system.
- Automated antibody stability studies, performed on 96-well plates using our VP-Capillary DSC system, aids protein engineering, pre-formulation and process development activities.
Our advanced protein characterization tool set enables detailed studies of;
- Antibody-target antigen interaction affinities and energetics by ITC.
- Antibody zeta potential and surface charge using Zetasizer Nano range.
- Antibody conformation and protein structure using Zetasizer Helix and DSC.
These characteristics are central to the understanding of antibody function, predicting / assessing stability and characterizing degradation pathways. Such knowledge can support the design of formulations and Bioprocessing parameters to ensure maximum stability and shelf-life.