Optimization of CE-SDS Method for Antibody Separation Based on Multi-Users Experimental Practices

Characterization workflow for fragments detected in capillary electrophoresis sodium dodecyl sulfate analysis of therapeutic monoclonal antibodies

Product-related fragments in monoclonal antibodies (mAbs) can have a significant impact on the efficacy and safety of the product. Capillary electrophoresis sodium dodecyl sulfate (CE-SDS) is a commonly used method for fragment quantification, but it has challenges in peak identification due to the inability to enrich components and the incompatibility of SDS with mass spectrometry (MS). This article presents a workflow for identifying peaks in CE-SDS analysis. The workflow involves comparing the migration time of peaks with that of standards and utilizing MS analysis to identify fragments. By employing this innovative systematic workflow, we successfully identified the CE-SDS impurity peaks of seven antibody products. Among them, four products exhibited characteristic fragments associated with disulfide bonds (light chain [LC], heavy-light [HL] chain, heavy-heavy [HH] chain, and HH-LC) and a glycosylation-related fragment non-glycosylated heavy chain. Additionally, one product showed a fragment formed by the connection of HC_C130 and HC_C130 , which is associated with a thioether bond. Furthermore, two other products displayed amino acid backbone breakage, with one product showing clipping at the HC region of A233 -G285 and the other product showing clipping at the HC regions of A97 -S158 and N342 -T366 . This workflow can be applied in early drug research, process development, or during the biologics license application stage to characterize fragments in therapeutic mAbs analyzed by CE-SDS.

Analysis of full and empty ratio of EV71 virus by using capillary zone electrophoresis

Hand, foot, and mouth disease is a serious public health problem, and the main pathogen is enterovirus 71 (EV71). Its capsid assembly mechanism including capsid protein processing has been widely studied. Full and empty capsids have different immunological efficacy. Therefore, tracking full/empty capsid ratio throughout the EV71 production process is important to ensure consistent product quality and proper dosing response. The analysis of full/empty capsid ratio of intact virus has been widely reported as well. A variety of techniques have been employed to evaluate the full/empty capsid ratios. However, there has not been a rapid, reproducible, and robust assay to determine the full/empty capsid ratios of final and in-process products. In this study, a novel assay based on capillary zone electrophoresis was established. The separation of full and empty species could be achieved within 10 min and the ratio of peak areas was used to calculate the full/empty capsid ratio directly. The results showed good reproducibility and linearity for the determination of full/empty capsid ratios.

Using Digestion by IdeS Protease to Improve Quantification of Degradants in Monoclonal Antibodies by Non-Reducing Capillary Gel Electrophoresis

Monoclonal antibodies (mAbs) have become predominant therapeutics by providing highly specific mechanisms of action enabling treatment of complex diseases. However, mAbs themselves are highly complex and require thorough testing and characterization to ensure efficacy and patient safety. In this regard, fragmentation is a degradation product of concern. The biotechnology industry uses capillary gel electrophoresis (CGE) to quantify fragmentation by electrophoretically resolving size variants, such as products resulting from partial reduction of interchain disulfides. However, standard CGE methods may not adequately separate less typical fragments, particularly when there is minimal size difference to the parent molecule. For mAb-1, a degradant only ∼11 kDa smaller than the intact mAb (∼149 kDa) was unable to be resolved under typical non-reducing conditions, preventing an accurate purity assessment and precluding tracking of product purity within stability studies. To address these deficiencies, a subunit-based non-reducing CGE method was developed to employ IdeS protease to produce F(ab')2 and Fc fragments, which resulted in baseline resolution of the clipped subunit species from its parent species. This enabled more accurate trending of purity throughout stability studies. Method characterization ensured that this subunit method monitored expected impurities observed by intact non-reducing CGE and thus could suitably replace non-reducing CGE in the release and stability testing panel. It also has the potential to replace reducing CGE based on its tracking of the deglycosylated Fc species. We believe this approach of utilizing proteases to develop subunit CGE methods for release and stability can be applied to other molecules when in need of resolving analogous fragments.

Capillary Electrophoresis-Mass Spectrometry (CE-MS) by Sheath-Flow Nanospray Interface and Its Use in Biopharmaceutical Applications

Both capillary electrophoresis (CE) and mass spectrometry (MS) technologies are powerful analytical tools that have been used extensively in the characterization of biologics in the biopharmaceutical industry. The direct coupling of CE with MS is an attractive approach, in that the high separation capability of CE and the ultrasensitive detection and accurate identification performance of MS can be combined to provide a powerful system for the analysis of complex analytes. In this chapter, we discuss the detailed procedure of carrying out CE-MS analysis using a nano sheath-flow interface and its applications including intact mass analysis of monoclonal antibodies and fusion proteins, and a biotransformation study of two Fc-FGF21 molecules in a single-dose pharmacokinetic mice study. Optimization processes, including the finetuning of CE conditions and MS parameters, are illustrated in this chapter, with focuses on method robustness and assay reproducibility.

Advances in capillary electrophoresis for the life sciences

Capillary electrophoresis (CE) played an important role in developments in the life sciences. The technique is nowadays used for the analysis of both large and small molecules in applications where it performs better than or is complementary to liquid chromatographic techniques. In this review, principles of different electromigration techniques, especially capillary isoelectric focusing (CIEF), capillary gel (CGE) and capillary zone electrophoresis (CZE), are described and recent developments in instrumentation, with an emphasis on mass spectrometry (MS) coupling and microchip CE, are discussed. The role of CE in the life sciences is shown with applications in which it had a high impact over the past few decades. In this context, current practice for the characterization of biopharmaceuticals (therapeutic proteins) is shown with CIEF, CGE and CZE using different detection techniques, including MS. Subsequently, the application of CGE and CZE, in combination with laser induced fluorescence detection and CZE-MS are demonstrated for the analysis of protein-released glycans in the characterization of biopharmaceuticals and glycan biomarker discovery in biological samples. Special attention is paid to developments in capillary coatings and derivatization strategies for glycans. Finally, routine CE analysis in clinical chemistry and latest developments in metabolomics approaches for the profiling of small molecules in biological samples are discussed. The large number of CE applications published for these topics in recent years clearly demonstrates the established role of CE in life sciences.