Polymer substrates for the separation and analysis of bio-therapeutics

Abstract

Modern medicine is rapidly evolving toward personalized treatments, where therapies are tailored to an individual’s genetic profile. This shift is driven by the promise of pharmacogenomics, which aims to match patients with the most effective medications based on their unique biological makeup. As a result, biotherapeutics made from biological sources like proteins, peptides, and antibodies are becoming increasingly important and may soon surpass traditional small-molecule drugs in both scope and impact.

Recent breakthroughs underscore this trend. GLP-1 peptides have emerged as effective tools for weight management, and mRNA-based vaccines, such as those developed for COVID-19, have demonstrated the power of biotherapeutics to address global health crises swiftly and effectively. However, these complex molecules pose significant challenges in manufacturing and quality control.

One major hurdle is ensuring purity. Even a single amino acid variation in a large peptide can affect a drug’s safety and efficacy. Detecting such minute differences requires highly specialized separation and analysis techniques. Without these, the risk of impurities in biopharmaceuticals remains a serious concern.

The thesis was conducted at Redstone Separations AB, a young company specializing in polymer-based separation technologies. The project focused on developing and evaluating new resin architectures for use in chromatographic separation. These resins were synthesized in-house and packed into HPLC columns using proprietary methods. The goal was to determine whether these novel materials could outperform existing commercial resins in separating complex biotherapeutic compounds.

Improved resin performance could lead to more precise separation of large biomolecules, enabling better detection of impurities and structural variants. This, in turn, enhances the safety and reliability of biopharmaceuticals. The project also aimed to identify the structural features of the resins that contributed to their performance, providing a roadmap for future improvements in polymer design.

The findings from this work contribute to the broader effort of making biotherapeutics safer and more effective. By advancing the tools used in purification and analysis, we move closer to a future where personalized medicine is not only possible but also reliable and accessible.

Popular Abstract

Introduction: Separation of bio-based compounds with therapeutic activities can be achieved on polymeric media and not only on traditional silica particles. It’s essential to identify upsides and downsides between the two material classes, such as pH range of use and mechanical tolerance, to understand which one is more suited to the specific separation mode.

Background: Current acceptable purity of some biological formulations is minimum 90% and the relative impurities can lead to side-effects, even strongly negative ones. Current traditional silica-based separation media undergo degradation at high pH, when cleaning of the stationary phase is carried out with hydroxide solutions to denature and wash away biological compounds. The most recent silica type (C) is able to withstand up to pH 11, but its cost renders it a difficult solution for scaling up production, and polymeric media may be the most satisfying solution in this regard, constituting a good middle ground between cost and performance.

Aim(s): The aim of this thesis project is to characterize styrene-divinylbenzene copolymers obtained through novel synthesis methods and their chromatographic performance in the development of separation and purification methods. This material was chosen for having a large research background already present, on which the company developed its own methods of synthesis.
Methods: Characterization of resins by light scattering, BJH analysis and optical microscope to determine particle and pore size, then test of the resins in HPLC columns with a few representative peptides to determine chromatographic performance, including column efficiency and resolution.

Results: Laser diffraction and microscope pictures are in agreement with each other and the particle size distributions are centered either at 6 or 11 µm (D50). BJH pore size analysis shows results mostly centered at around 250 Å, however a few samples have pore sizes in the 60 Å range, for both smaller and larger particles. The chromatographic gradient was optimized throughout the whole project for the resin basis, regardless of the column length and particle size, adjusting the flow for each column until a similar starting pressure was achieved. The HETP parameter was evaluated for each column, as well as the resolution of the different peaks.

Conclusion: Thanks to proprietary synthesis methods, a new series of polymeric materials were developed and, after screening, a few representative samples provided comparable results when compared to current commercial alternatives.

• author: Zappa, Lorenzo
• supervisor: Ecevit Yilmaz
• organization: Department of Chemistry
• course: KEMR30 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Chemistry
• keywords: biodrug, peptide, polymer, purification, separation, analytical chemistry
• language: English
• id: 9200609
• date added to LUP: 2025-06-23 11:20:59
• date last changed: 2025-06-23 11:20:59