Determining Charge Heterogeneity for a Fusion Protein Using Imaged Capillary Isoelectric Focusing (icIEF)
1. Overview of the Case Study
Accurate identification and control of charge heterogeneity are critical aspects of biologics and biosimilars development, necessitating robust analytical methods for reliable characterization of protein variants.
To support product evaluation, Adgyl Lifesciences developed an imaged capillary isoelectric focusing (icIEF) method for a fusion protein and performed formulation sample analysis. The study focused on developing a suitable method to characterize charge heterogeneity and generate reliable analytical data for sample evaluation.
2. Challenges
The successful execution of this study required addressing key analytical challenges:
- Traditional techniques such as Ion Exchange Chromatography (CEX) and gel electrophoresis often struggle to provide the resolution and robustness required for accurate characterization of charge heterogeneity.
- Although various preparative isoelectric focusing (IEF) methods have been developed over the years, they have several limitations, including high levels of contaminating ampholytes and complex fractionation and isolation procedures.
3. Our Approach
To overcome this challenge, we implemented a systematic method development strategy using the Maurice™ platform, an industry-standard instrument for imaged capillary isoelectric focusing (icIEF) and charge heterogeneity characterization of biotherapeutics.
- Optimized protein concentration to achieve adequate signal.
- Selected isoelectric point (pI) markers based on the charge heterogeneity observed.
- Optimized urea concentration to achieve adequate solubility and reduce aggregation.
- Evaluated several ampholyte combinations and concentrations, with inclusion of Servalyt to improve peak resolution
4. Outcomes
- Successfully developed an icIEF method for the fusion protein.
- Generated reliable charge heterogeneity profiles for formulation samples.
- Utilized the developed method for analysis of 50 samples.
5. Conclusion
We successfully addressed the challenge of determining charge heterogeneity in a fusion protein through the development of an optimized icIEF method. By systematically optimizing critical method parameters and evaluating multiple separation conditions, a fit-for-purpose analytical method was established.
The developed method was successfully utilized for the analysis of 50 samples, generating reliable analytical data and supporting product evaluation.
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