0      0

Charge Heterogeneity Analysis via a Novel, Rapid Chip-based icIEF-MS Approach for Therapeutic Proteins

‐ Sep 29, 2020 8:20am

Charge variants are critical quality attributes and must be controlled to ensure stability and process
consistency for biotherapeutics. Multiple post translational modifications (PTMs) can induce charge
heterogeneity, including clipping of C-terminal lysine, glycation, deamidation, etc. Modifications of charge
profiles may potentially impact structural and biological activities. Traditionally, charge profiles of
biotherapeutics are monitored through liquid chromatography-based methods, such as ion exchange
chromatography, or isoelectric focusing methods, such as imaged capillary isoelectric focusing. To directly
identify PTMs, these methods need coupling with high-resolution mass spectrometry. Currently, MS
identification of an unknown icIEF peak requires multi-step processes -scale-up of the LC-based separation,
fractionation, icIEF analysis to confirm the fraction isoelectric point (pI), and off-line MS analysis.
Therefore, a more comprehensive analytical tool is necessary to streamline the workflow and provide
extensive characterization of charge heterogeneities.
We describe an approach utilizing a novel platform coupling an icIEF microchip with an on-line Hi-Res MS
via electrospray ionization (ESI) emitter (BlazeTM System, Intabio, Inc.). Method conditions for icIEF
separation, and transfer to MS for analysis were optimized to achieve a 16-min high throughput
characterization. Additional comparability studies with traditional icIEF analysis on the Maurice platform
were conducted to ensure reproducibility of charge profiles and ease of assay transfer. Charge profiles were
further analyzed via SCIEX Triple TOF 5600 system to understand distribution of PTMs on intact level and
data were processed using Byos® Software from Protein Metrics. Reduced peptide mapping was employed,
providing additional information on changes under accelerated conditions. Stressed materials, including
light and high pH stress materials, were characterized to demonstrate capability of the new platform to detect changes and provide information on PTMs associated with degradation pathways. This novel platform
enables extensive characterization and identification of charge heterogeneity- associated PTMs and other
structural information on the intact level with a streamlined workflow.


You must be logged in and own this session in order to post comments.