As advances in cell-culture technology have resulted in more productive and efficient therapeutic protein upstream processes, the pressure on downstream processing has grown with often protein purification being a bottleneck in protein manufacture. Conventional column chromatography, which is typically operated in batch mode, may be inefficient, costly, and ill-suited for adaptation to single-use systems. Continuous countercurrent tangential chromatography (CCTC) has the potential to address these limitations of conventional column chromatography.
Issues with current technology
For protein purification, the low efficiency of batch-column chromatography operations results in high capital costs, high operating costs, and long process times, according to Oleg Shinkazh, CEO of Chromatan Corporation, a chromatography solutions provider. “These issues are particularly noticeable in clinical manufacturing, where expensive resins such as Protein A are only used to 10% of their useful lives,” he notes. In addition to purification process bottlenecks, adds Kent Smeltz, President of ASI, a manufacturer of single-use systems and technologies, there is a significant technology gap with respect to the adoption of single-use systems for protein purification. “Purification operations are the only ones that have not been economically designed for single use,” he says.
Combining the principles of chromatography and continuous processing
Continuous countercurrent tangential chromatography combines the principles of chromatography and continuous/conveyor-belt processing with liquid–liquid extraction and tangential flow filtration to create the first “true moving bed” technology (as opposed to simulated moving bed) that is capable of large-scale, column-free capture purification of biologics, according to Shinkazh.
Initially developed by Chromatan and now under joint development by Chromatan and ASI, the Evopure system preserves the robust resin interaction and buffer chemistry of column chromatography while using a flow path specifically designed for single-use operation.
“In contrast to conventional-column chromatography, where the resin particles are packed in a fixed-bed column, in our system the chromatography resin is suspended in a slurry that is pumped through the system in a manner similar to that of a conveyor belt. The system is designed so that the resin is simultaneously ‘operated on’ by the same types of chromatographic operations used in conventional chromatography, such as binding, washing, elution, stripping, etc. As the resin flows through a series of static mixers and hollow fiber membrane modules, the buffers used in the binding, washing, and elution steps flow countercurrent to the resin, enabling high-resolution separations while reducing the amount of buffer needed for protein purification. The flow path is a sophisticated single-use tubing set that consists of static mixers and tangential flow filters in series with built-in countercurrent recycling loops similar to those used in liquid/liquid extraction processes,” he explains.
Reduced costs, scalable, and single-use
The Evopure system addresses three critical needs of the purification industry—cost savings on capital and operational costs, a single-use and sterile flow path, and linear scalability, according to Smeltz. Specifically, with CCTC, throughput is increased 5- to 10-fold when compared to conventional columns, which enables high resin cycling in a single batch. CCTC thus, makes single-use capture practical and introduces significant cost savings of up to 65% to the end user, according to Shinkazh.
The fact that the technology is column-free is also important for end users. Shinkazh points out that with CCTC, there is no longer the need to spend time and resources on column packing and qualification, column cleaning, cleaning validation, and resin storage. “As a result, the implementation of a CCTC system will greatly simplify the purification process and enable much more flexibility in manufacturing operations,” he observes.
Partnering for rapid commercialization
ASI and Chromatan announced in April 2013 an exclusive agreement to combine their development, sales, marketing, and manufacturing efforts to bring the CCTC purification technology to market. Under the terms of the agreement, ASI and Chromatan will complete the development of the newly patented technology and launch the purification system during the fourth quarter of 2013.
“ASI and Chromatan are very well-suited to bring this innovation to market because each company brings to the table the specialized expertise required,” notes Smeltz. Specifically, he indicates that ASI has strong capabilities with respect to the development of turnkey single-use solutions all the way from design through marketing, manufacturing, and shipping of product. “ASI is dedicated to introducing single-use technologies to the market that differentiate themselves from current single-use technology. CCTC is such a technology,” Smeltz adds. In addition, the company has a strong quality system that enables it to custom-configure solutions to each customer’s process while meeting the quality and documentation standards that are required.
As the original innovator of the CCTC technology, Chromatan has been effective at developing systems for feasibility testing and generated a significant amount of data. The company has conducted extensive experiments on the use of CCTC for the purification of an IgG4 monoclonal antibody from a model feed containing bovine serum albumin and myoglobin using a protein A affinity resin (1) and the separation of a model protein mixture containing bovine serum albumin and myoglobin using a commercially available anion exchange resin (2).
ASI has carefully reviewed the data and believes that working with Chromatan will make it possible for the company to not only better serve existing customers, but also bring in new customers that have not previously been exposed to the company’s services, according to Smeltz. “We believe in the technology. Chromatan has done a fantastic job of creating an innovation that is going to change the course of protein purification in bioprocessing. Together, we can better serve the industry as a whole,” he adds.
For Shinkazh, the partnership will also allow both companies to benefit from each other’s strengths and grow their businesses. Chromatan will be responsible for the technical sales and technical support of customers. ASI will be responsible for the hardware and single-use component manufacturing for the partnership. In addition, the companies will jointly design the commercial Evopure system and comarket and cobrand the technology.
Helping where it hurts the most
The first continuous countercurrent tangential chromatography systems will be designed for use in the application where the customer is hurting the most—protein A capture chromatography for monoclonal antibodies, according to Shinkazh. “We have picked this application as our initial target because there will be an immediate cost savings and speed to the process.”
Evopure is, however, a platform technology. In the near future, ASI and Chromatan will be exploring its use for ion-exchange chromatography and other more niche-type applications. Both ASI and Chromatan see their partnership as a long-term investment in innovation, according to Smeltz. “There is very strong evidence that our industry is moving towards flexible, single-use facilities, and we believe that this partnership will result in bringing to market an exciting new technology that can truly serve our customers in that regard.”
1. B. Napadensky et al., Separation Science and Technology 48 (9) 1289-1297 (2013).
2. O. Shinkazh et al., Biotechnol. Bioeng.; 108 (3) 582–591 (2011).