Amsphere® A3 resin: Consistent mAb purification after CIP
Section overview
- Protein A chromatography resin selection
- Experimental overview: Life cycle studies
- Consistent dynamic binding capacity and product recovery
- Consistent impurity removal and purification performance
- Experimental overview: Stability studies with 0.5 M NaOH
- Alkaline stability: Dynamic binding capacity and purification performance
- Frequently asked questions
Protein A chromatography resin selection
Whether developing a new process or looking for a resin for secondary sourcing, when considering a new Protein A resin for a monoclonal antibody (mAb) capture step you may evaluate binding capacity, flow rates, alkaline stability and resin lifetime performance.
Amsphere® A3 resin is a well-established protein A resin for purification of mAbs and antibody derivatives, e.g. Fc-fusion proteins and bispecific mAbs, and is frequently considered as a platform resin for a range of antibody molecules.1,2,3
Key takeaways: Amsphere® A3 is a well-established Protein A resin for purification of mAbs and antibody derivatives offering high DBC and excellent productivity over a wide operating window. Results of this work demonstrated:
Collectively, these results reinforce the alkaline stability of Amsphere® A3 resin. |
Key specifications of Amsphere® A3 resin:
- Base Bead: Methacrylic copolymer, average particle size (d50): ~50 µm
- Ligand: Recombinant Protein A expressed in Escherichia coli
- Dynamic Binding Capacity (DBC10%): ~54 g/L at 4 min residence time (RT)
Visit our Affinity chromatography resin page for more information on our affinity chromatography portfolio.
Resin lifetime is a key parameter for selection of any resin as it impacts resin volume requirements and manufacturing costs. Sodium hydroxide (NaOH) is a widely used sanitizing and cleaning-in-place (CIP) agent for Protein A chromatography resins and alkaline stability is therefore a critical requirement for maintaining consistent resin performance across repeated CIP cycles. This technical article summarizes the lifetime performance of Amsphere® A3 over 100 cycles of loading and CIP with 0.1 M NaOH. Results of further stability studies with 0.5 M NaOH are also reported.
Experimental overview: Resin life cycle studies
Test material was a sterile-filtered clarified mAb harvest (1.1 g/L). The feed was loaded onto a 1 mL column with 0.5 cm internal diameter (ID) x 5 cm bed height (BH) containing Amsphere® A3 resin at a residence time (RT) of 5 min over 100 cycles as described in the protocol below.
Consistent dynamic binding capacity and product recovery
High DBC10% at short residence times is essential for high productivity and must be maintained through a high number of cycles to ensure reliable process performance.
The DBC10% and recovery of mAb were assessed over 100 cycles of loading and CIP using Amsphere® A3 resin under CIP conditions of 0.1 M NaOH (30 min contact time) every cycle and 0.5 M NaOH (10 min contact time) every 10 cycles. Figure 1 shows that the DBC10% was maintained at initial levels and the mAb recovery was above 80% throughout the study, confirming stable binding capacity and product recovery across all 100 cycles.
Figure 1.Dynamic binding capacity at 10% breakthrough (DBC10%) for Amsphere® A3 chromatography resin and mAb recovery over 100 operational cycles.
Consistent impurity removal and purification performance
Similar to DBC10% and product recovery, consistent impurity removal throughout resin lifetime is essential to meet product purity specifications.
Analysis of impurity profiles in elution pools revealed little change in HCP or DNA log reduction values (LRV) across 100 cycles using Amsphere® A3 resin (Figure 2). Over the 100 cycles analyzed, HCP was consistently reduced by 2 LRV and DNA by approximately 3 LRV.
Figure 2.Reduction of HCP and DNA levels in elution pools following purification on Amsphere® A3 resin over 100 operational cycles.
Analysis of the elution pool characteristics throughout the 100 cycles confirmed consistent performance: pH was stable between 4.5-5, and leached Protein A ligand levels were between 15-20 ppm within the first 20 cycles (Figure 3).
Figure 3.Levels of leached Protein A and elution pool pH over 100 operational cycles.
Figure 4 shows the consistent performance of Amsphere® A3 throughout resin lifetime: when elution profiles from cycle 1 and cycle 100 are overlaid, the elution volumes and peak shapes are almost identical, confirming consistent resin performance across all cycles of loading and CIP.
Figure 4.Overlaid UV280 nm absorbance, conductivity and pH elution profiles from cycle 1 and cycle 101 using Amsphere® A3 resin.
Experimental overview: Stability studies with 0.5 M NaOH
Feed material was a human polyclonal antibody (5.1-5.4 g/L). All studies used Amsphere® A3 resin packed in a 1 mL MediaScout™ MiniChrom™ column (0.5 cm I.D., 5 cm BH). All studies were performed on an AKTA Avant™ 25 system.
The initial DBC10% was determined at the beginning of the study. All cycles were performed according to the protocol outlined below, with DBC10% assessed every 15th cycle.
Alkaline stability: Dynamic binding capacity and purification performance
Figure 5 shows the percentage change in DBC10% for the polyclonal antibody over 100 cycles of CIP with 0.5 M NaOH, 15 min contact time on Amsphere® A3 resin. At the start of the study DBC10% was 58 g/L, which reduced to 53 g/L after 100 CIP cycles – 91% of the starting value.
Figure 5.Change in DBC10% with human IgG through 100 operational cycles on Amsphere® A3 resin after CIP with 0.5 M NaOH (15 min contact time).
To further assess Amsphere® A3 resin alkaline stability, impurity removal was compared on a new column and a column that had been subject to ~100 cycles of CIP with 0.5 M NaOH (15 min contact time). These studies used a mAb, loaded to 40 g/L resin and HCP and DNA levels were measured in both the feed and eluate samples.
Analysis of HCP and DNA levels indicated consistent impurity removal performance of Amsphere® A3 resin with both new and used resin, Table 1.
Table 1. Comparison of HCP and DNA clearance between a new column containing Amsphere® A3 resin and a column following 101 cycles of CIP with 0.5 M NaOH (15 min contact time).
These data confirm consistent Amsphere® A3 resin performance in the presence of 0.5 M NaOH CIP solution over 100 cycles.
Frequently asked questions
What do you mean by Amsphere® Protein A resins are now part of our portfolio?
The chromatography business of JSR has recently been acquired and we are in the process of integrating these well-established affinity resins into our Process Solutions portfolio, strengthening our Protein A chromatography capabilities with best-in-class products.
How can I order Amsphere® Protein A resins?
In the short term you can use the form on the website or reach out to your account representative.
What are Amsphere® Protein A resins used for?
Amsphere® Protein A resins are used for the affinity capture of monoclonal antibodies (mAbs) and their derivatives in biopharmaceutical manufacturing. Amsphere® A+ is designed for high-titer and intensified processes, including concentrated fed-batch and continuous bioprocessing, where maximum dynamic binding capacity at low residence times and long-term caustic stability are critical. Amsphere® A3 is an established platform resin suited for a broad range of mAb capture applications, offering a well-balanced productivity and cost-of-goods profile, and is a proven choice for dual sourcing strategies.
What is the difference between Amsphere® A3 and Amsphere® A+?
Both Amsphere® A3 and Amsphere® A+ are Protein A affinity resins designed for mAb capture, but they are optimized for different process strategies. Amsphere® A3 is an established platform resin offering consistent, reproducible performance across a broad range of mAbs and their derivatives, with a well-balanced productivity and cost-of-goods profile. It is well-suited for scalable platform processes and is a proven choice for dual sourcing strategies. Amsphere® A+ is optimized for maximum productivity in high-titer and intensified processes, delivering outstanding dynamic binding capacity at low residence times. Its exceptional caustic stability and long cycle lifetime make it the right choice for concentrated fed-batch and continuous bioprocessing platforms where process demands are high.
How do I choose between Amsphere® A3 and Amsphere® A+?
The choice between Amsphere® A3 and Amsphere® A+ depends on your specific process requirements. If you are running a standard mAb capture process and are looking for a reliable, scalable platform resin with a well-balanced productivity and cost-of-goods profile, Amsphere® A3 is the right choice. It is also well-suited for dual sourcing strategies, offering a qualifiable alternative that reduces single-supplier risk. If your process is high-titer or intensified, such as concentrated fed-batch or continuous bioprocessing, and maximum dynamic binding capacity at low residence times is a key requirement, Amsphere® A+ is the recommended option. Its exceptional caustic stability and long cycle lifetime further support the extended resin reuse demands of intensified and continuous manufacturing operations.
I’m thinking of intensified processing, which Protein A resin would you recommend?
For intensified processing, Amsphere® A+ is the recommended Protein A resin. It is specifically engineered to meet the process demands of high-titer and intensified manufacturing modes, including concentrated fed-batch and continuous bioprocessing, delivering outstanding dynamic binding capacity at low residence times. Its exceptional caustic stability and long cycle lifetime ensure reliable performance across extended resin reuse, which is a critical requirement in both intensified batch and continuous manufacturing operations.
For mAb capture in a standard batch process, which resin would you recommend?
For mAb capture in a standard batch process, Amsphere® A3 is the recommended choice. It is an established platform resin offering consistent, reproducible Protein A capture performance across a broad range of mAbs and their derivatives. Its well-balanced productivity and cost-of-goods profile makes it well-suited for platform process strategies that prioritize operational robustness and scalability. Amsphere® A3 is also a proven choice for dual sourcing strategies, providing supply security without compromising process performance.
Are Amsphere® resins supported by the Emprove® Program?
Amsphere® A+ and Amsphere® A3 will be included in the Emprove® Program soon. Until then, please reach out to your local Merck representative for comprehensive documentation packages and support with qualification, risk assessment, and regulatory activities.
Are Amsphere® resins used only for capture?
Yes. Amsphere® Protein A resins are specifically designed for the capture step in monoclonal antibody (mAb) purification. For downstream purification steps beyond capture, additional chromatography technologies such as mixed-mode resins and membrane-based solutions are used to address impurity removal and polishing requirements.
What is the advantage of Amsphere® resins compared to agarose-based Protein A resins?
Yes. Amsphere® Protein A resins are specifically designed for the capture step in monoclonal antibody (mAb) purification. For downstream purification steps beyond capture, additional chromatography technologies such as mixed-mode resins and membrane-based solutions are used to address impurity removal and polishing requirements.
What is dual sourcing and why should I consider it for my Protein A capture step?
Dual sourcing is a supply chain strategy in which two qualified resin suppliers are maintained for the same process step, ensuring that manufacturing can continue uninterrupted in the event of supply disruptions, quality issues, or regulatory holds with one supplier. For biopharmaceutical manufacturers, qualifying a second Protein A resin reduces single-supplier dependency and strengthens overall supply chain resilience, which is increasingly important in a global manufacturing environment. Amsphere® A3 is an established choice for dual sourcing qualification, offering consistent, reproducible Protein A capture performance across a broad range of mAbs and their derivatives, with a well-balanced productivity and cost-of-goods profile that supports straightforward process comparability.
Why is high caustic stability important for a Protein A resin?
Caustic stability refers to a resin's ability to withstand cleaning-in-place with sodium hydroxide (NaOH) solutions, which are the industry standard for sanitization between purification cycles. A resin with high caustic stability maintains its dynamic binding capacity and structural integrity across many cycles of NaOH exposure, ensuring consistent process performance over the resin lifetime. This is particularly critical in high-cycle processes such as continuous bioprocessing or intensified fed-batch manufacturing, where resins are subjected to frequent and aggressive cleaning regimens. High caustic stability directly translates into extended resin reuse, reduced resin replacement frequency, and lower cost-of-goods per gram of purified product.
How does Amsphere® improve cost of goods?
Amsphere® resins contribute to improved cost of goods through two key factors: high dynamic binding capacity and long resin lifetime. A high dynamic binding capacity at low residence times allows more product to be captured per cycle and per liter of resin, reducing the required resin volume and column size for a given production output. The exceptional caustic stability of Amsphere® resins supports extended resin reuse across many cycles with aggressive cleaning-in-place protocols, reducing the frequency of resin replacement and spreading the resin investment across a higher number of purification cycles. Together, these properties enable a more productive and cost-efficient capture step, contributing to a favorable cost-of-goods profile across the resin lifetime.
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