Introducing the Next Generation of High-Performance Protein A Resin

Johanna Howson, lead applications scientist, Purolite

David Cartmell, product manager, Purolite

Ecolab is committed to the long-term success of its clients. The company continually invests in global capacity and new markets for business continuity. Cartmell emphasized the value of end users speaking with their raw-materials suppliers: “After the pandemic, many clinical trials and companies were hugely affected by security supply.” Purolite and Ecolab have highlighted supply-chain insecurity “as something that cannot happen again.” Ecolab and its subsidiary Purolite maintain growing innovation pipelines as new molecules enter drug manufacturing and require specialized resins.

Purolite’s new protein A resin, the DurA Cycle resin, purifies monoclonal antibodies (mAbs) and associated protein constructs under variable cleaning strategies. The DurA Cycle resin is designed to drive innovation and performance while reducing the cost of goods (CoG) for manufacturing processes. Developed using Purolite’s Jetting technology, the resin facilitates process consistency and supports sustainability initiatives. The Jetting technology offers a faster, more environmentally conscious process for manufacturing agarose beads with uniform particle-size distribution.

Cartmell listed four parameters for developing long-lasting products: caustic stability, protease resistance, capability for mild pH elution, and high capacity. Many existing processes use 0.1 M sodium hydroxide for resin cleaning. However, some traditional protein A resins are not built for such caustic conditions and thus experience a subsequent loss in dynamic binding capacity (DBC). Cleaning-in-place (CIP) strategies that instead use 0.5 M sodium hydroxide could prevent ligand leakage and productivity loss. As cell and expression titers increase in upstream processes, so too do the number of proteases, increasing risks of protein A leakage. Innovative products such as the Praesto Jetted A50 HipH resin resist protease formation to decrease the chance of leakage. Low pH levels can contribute to aggregation, reducing yields at harvest. A broad pH elution range can improve process optimization and address aggregation causes. And high capacity is crucial to productivity because it amounts to increased affinity for various molecule types.

Howson discussed the DBC of the DurA Cycle resin. Two tests were run, one on a polyclonal antibody (pAb) and another on an immunoglobulin G (IgG) mAb. The DurA Cycle resin and two market-leading protein A resins were used in both tests. The DurA Cycle resin exhibited the highest capacity at 80 g/L in a typical antibody-purification process. Because of its jetted base matrix, the DurA Cycle resin showed improved mass transfer, enabling high capacity at short residence times. A 65-g/L capacity was achieved at a three-minute residence time.

As increasingly complex molecules enter development and production, aggregation will become even more of a concern. In a typical protein process, elution occurs at pH ≤3.7. Acid-sensitive molecules are prone to aggregation in such conditions, resulting in yield loss. Eluting at milder pH levels compared with traditional protein A steps has been shown to improve impurity removal in mAbs and bispecific antibodies (bsAbs). In a study comparing the performance of Purolite’s DurA Cycle and Jetted A50 HipH resins with two competitor resins, Purolite’s products had the highest maximum elutions peaks at pH 4.23 and pH 4.68, respectively.

The DurA Cycle resin offers improved caustic stability for a breadth of different molecules, leading to consistently low protein A leakage. After a 60-hour incubation at 37 °C in four feed streams, no capacity loss was observed for the DurA Cycle resin. And in an accelerated alkaline stability test, the resin maintained >90% of its original capacity after a 300-hour incubation period in 0.1 M sodium hydroxide, demonstrating the potential for reusing the resin across many cycles. Over 90% of the original capacity is still maintained after an 80-hour exposure at 0.5 M sodium hydroxide.

Purolite continually incorporates customer feedback into its new products. “If you’re not addressing the needs, then there’s no point [in] doing it in the first place,” Cartmell said. Clients continue to seek cost-saving solutions, which is why the DurA Cycle resin is designed to be a fit-for-purpose resin that can last many cycles.

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