Buffer Consumption Research Articles

A regressive approach to the design of continuous capture process with multi-column chromatography for monoclonal antibodies

Although empirical methods have been introduced in the process development of continuous chromatography, the common approach to optimize a multi-column continuous capture chromatography (periodic counter-current chromatography, PCCC) process heavily relies on numerical model simulations and the number of experiments. In addition, different multi-column settings in PCCC add more design variables in process development. In this study, we have developed a rational method for designing PCCC processes based on iterative calculations by mechanistic model-based simulations. Breakthrough curves of a monoclonal antibody were measured at different residence times for three protein A resins of different particle sizes and capacities to obtain the parameters needed for the simulation. Numerical calculations were performed for the protein sample concentration in the range of 1.5 to 4 g/L. Regression curves were developed to describe the relative process performances compared with batch operation, including the resin capacity utilization and the buffer consumption. Another linear correlation was established between breakthrough cut-off (BT%) and a modified group composed of residence time, mass transfer coefficient, and particle size. By normalizing BT% with binding capacity and switching time, the linear regression curves were established for the three protein A resins, which are useful for the design and optimization of PCCC to reduce the process development time.

Mechanistic modeling of continuous capture step purification of biosimilar monoclonal antibody therapeutic

AbstractBACKGROUNDContinuous multicolumn Protein A chromatography offers various advantages for capture stage purification of monoclonal antibody therapeutics, like higher productivity and resin capacity utilization, lower buffer consumption, small footprint, etc. Due to the complexity of the continuous process, experimental optimization is time‐consuming and cost‐intensive. This investigation proposes a hybrid process development approach integrating experimental and mechanistic modeling for time‐ and cost‐effective development and optimization of continuous Protein A affinity chromatography.RESULTSProductivity and capacity utilization of the continuous CaptureSMB process under varying operating conditions were predicted using the Chromatography Analysis and Design Toolkit (CADET) framework and validated with experimental results. Effects of critical process parameters like feed concentration (c0), loading breakthrough (s) and residence time (RT) on productivity and capacity utilization were evaluated. Model predictions were validated using the experimental results proving the reliability and feasibility of the modeling approach. At 15.00 ± 0.20 mg mL–1 feed model mAb concentration, the model‐based approach predicted the best performance giving 27.56 g L–1 h–1 productivity (RT = 2 min, s = 80%) using MabSelect™ PrismA resin. This productivity prediction was validated by performing the continuous CaptureSMB experiment at the same operating conditions and was found to be 25.59 g L–1 h–1 with a root mean square error of 1.96.CONCLUSIONSThe hybrid process development and optimization approach for CaptureSMB purification of biosimilar mAb purification is demonstrated and validated using the experimental and model‐based framework. The observed results showcase the effectiveness of the proposed hybrid process development approach, enabling a better understanding of the chromatography process and parameters affecting the CaptureSMB process. © 2021 Society of Chemical Industry (SCI).

Exploration of fiber-based cation exchange adsorbents for the removal of monoclonal antibody aggregates

Cation exchange chromatography (CEX) is a widely used technique for the removal of monoclonal antibody (mAb) aggregates. At present, resins are mainly used for this purpose, as convective types of adsorbents such as membrane adsorbers (MAs) have often not demonstrated overall comparable performance for this particular application. Fiber-based adsorbents can overcome the current limitations of MAs with respect to permeability, binding capacity, and adsorbent cost, and could therefore be a viable alternative to resins for the removal of mAb aggregates. It has not been evaluated, however, whether and under which conditions the use of such adsorbents is feasible for this purpose.In the present study, the use of fiber-based CEX adsorbents for mAb aggregate removal was examined. Two types of fiber-based adsorbents, an uncontrolled grafted and a controlled grafted fiber-based adsorbent, were evaluated with respect to permeability, dynamic mAb binding capacity (DBC), resolution capabilities, and the performance in bind and elute (B/E) and frontal chromatography mode with respect to typical performance indicators. The permeabilities of the fiber-based adsorbents ranged from 200 to 1700 mD, making it possible to use the fiber-based adsorbents at larger bed heights than membrane adsorbers with fast mobile phase velocities. Antibody DBCs ranged from 20 to 41 g/L at 150 cm/h, and at higher mobile phase velocities exceeded the DBC of an existing resin material, Poros 50 HS, which has frequently been used for aggregate removal. Both fiber types showed good resolution capabilities of monomer and aggregates, and provided better resolution per column length than Poros 50 HS. Typical purity and yield constraints were fulfilled for both fiber types in both B/E and frontal chromatography mode for mobile phase velocities ranging up to 480 cm/h and 1060 cm/h. The overall performance of the controlled grafted fibers was found to be superior to the performance of uncontrolled grafted fiber-based adsorbents due to higher productivity and lower buffer consumption. The overall performance of the fiber-based adsorbents was found to be comparable to the performance of Poros 50 HS at typical operating conditions.The results in this study indicate that the use of fiber-based adsorbents for mAb aggregate removal is feasible with a performance that is comparable to the performance of an existing resin material. Depending on the cost of the adsorbents and the use scenario, the usage of such adsorbents could be beneficial.

Integrating critical chain project management with last planner system for linear scheduling of modular construction

PurposeThe purpose of this paper is to present a new method for project tracking and control of integrated offsite and onsite activities in modular construction considering practical characteristics associated with this type of construction.Design/methodology/approachThe design embraces building information modelling and integrates last planner system (LPS), linear scheduling method (LSM) and critical chain project management (CCPM) to develop tracking and control procedures for modular construction projects. The developed method accounts for constraints of resources continuity and uncertainties associated with activity duration. Features of proposed method are illustrated in a case example for tracking and control of modular projects.FindingsComparison between developed schedule and Monte Carlo simulation showed that baseline duration generated from simulation exceeds that produced by developed method by 12% and 10% for schedules with 50% and 90% confidence level, respectively. These percentages decrease based on interventions of members of project team in the LPS sessions. The case example results indicate that project is delayed 5% and experienced cost overrun of 2.5%.Originality/valueDeveloped method integrated LPS, LSM and CCPM while using metrics for reliability assessment of linear schedules, namely, critical percent plan complete (PPCcr) and buffer index (BI). PPCcr and BI measure percentage of plan completion for critical activities and buffer consumption, respectively. The developed method provides a systematic procedure for forecasting look-ahead schedules using forecasting correction factor Δt and a newly developed tracking and control procedure that uses PPCcr and BI. Quantitative cost analysis is also provided to forecast and monitor project costs to prove the robustness of proposed framework.

Process Intensification for the Purification of Peptidomimetics: The Case of Icatibant through Multicolumn Countercurrent Solvent Gradient Purification (MCSGP)

Biopharmaceuticals are subjected to very strict purity requirements to be marketed. At the same time, peptides and other biomolecules are industrially synthesized through techniques (e.g., solid-phase synthesis) often leading to the formation of many impurities with molecular characteristics very similar to the target product. Therefore, the purification of these mixtures via preparative chromatography can be very challenging. This typically involves ternary or central-cut separations, characterized by chromatograms where the central peak, corresponding to the target product, exhibits significant overlapping on both sides with impurities slightly more or less adsorbable. In single-column (batch) preparative chromatography, this leads to a typical yield-purity tradeoff, meaning that high purity can be obtained at the cost of low yield and vice versa, with obvious consequences on the overall production costs. This study demonstrates how this limitation can be alleviated using the continuous countercurrent operating mode, conducted on a multicolumn system, as a tool for process intensification. In particular, the Multicolumn Countercurrent Solvent Gradient Purification (MCSGP) process has been applied to the purification of an industrial crude mixture of icatibant, which is a peptidomimetic antagonist of bradykinin B2-receptor that has been recently also considered for the treatment of patients affected by COVID-19 disease. It is shown that MCSGP allows conjugating process simplicity (using only two columns) with a significant improvement in process performance, compared to the corresponding batch process. This includes all process performance parameters: yield, productivity, and buffer consumption for a given purity specification of icatibant.

Project buffer sizing and dynamic buffer consumption algorithm in power generation construction

PurposeThe aim of this research is to propose a buffer sizing and buffer controlling algorithm (BSCA) as a heuristic algorithm for calculating project buffer and feeding buffers as well as dynamic controlling of buffer consumption in different phases of a wind power plant project in order to achieve a more realistic project duration.Design/methodology/approachThe BSCA algorithm has two main phases of planning and buffer sizing and construction and buffer consumption. Project buffer and feeding buffers are determined in the planning and buffer sizing phase, and their consumption is controlled in the construction and buffer consumption phase. The heuristic algorithm was coded and run in MATLAB software. The sensitivity analysis was conducted to show the BSCA influence on project implementation. Then, to evaluate the BSCA algorithm, inputs from this project were run through several algorithms recently presented by researchers. Finally, the data of 20 projects previously accomplished by the company were applied to compare the proposed algorithm.FindingsThe results show that BSCA heuristic algorithm outperformed the other algorithms as it shortened the projects' durations. The average project completion time using the BSCA algorithm was reduced by about 15% compared to the previous average project completion time.Originality/valueThe proposed BSCA algorithm determines both the project buffer and feeding buffers and simultaneously controls their consumption in a dynamic way.

Development of a Mobile Analytical Chemistry Workstation Using a Silicon Electrochromatography Microchip and Capacitively Coupled Contactless Conductivity Detector.

Capillary electrochromatography (CEC) is a separation technique that hybridizes liquid chromatography (LC) and capillary electrophoresis (CE). The selectivity offered by LC stationary phase results in rapid separations, high efficiency, high selectivity, minimal analyte and buffer consumption. Chip-based CE and CEC separation techniques are also gaining interest, as the microchip can provide precise on-chip control over the experiment. Capacitively coupled contactless conductivity detection (C4D) offers the contactless electrode configuration, and thus is not in contact with the solutions under investigation. This prevents contamination, so it can be easy to use as well as maintain. This study investigated a chip-based CE/CEC with C4D technique, including silicon-based microfluidic device fabrication processes with packaging, design and optimization. It also examined the compatibility of the silicon-based CEC microchip interfaced with C4D. In this paper, the authors demonstrated a nanofabrication technique for a novel microchip electrochromatography (MEC) device, whose capability is to be used as a mobile analytical equipment. This research investigated using samples of potassium ions, sodium ions and aspirin (acetylsalicylic acid).

Determination of early warning time window for bottleneck resource buffer

As an advanced warning system, resource buffer can notify the use of resources and provide added protection to critical chain activities. However, most of the existing studies in the literature focus on locating actual time buffers at various locations. In this study, we locate bottleneck resource buffers along the critical chain and determines optimal time windows for the first time. Drawing on the theory of constraints, we take into account factors such as bottleneck resource sensitivity, the idle cost, the start time flexibility and the work flow on the critical chain, and develop a quantitative model for the optimal time window determination of resource buffer. The proposed method is tested and compared with the currently widely adopted buffer management method. Results of the computational experiment of the proposed method demonstrates its relative dominance over the predominant buffer management approach in terms of overall completion time, project cost, the probability of delay and the average buffer consumption ratio.

An integrated continuous downstream process with real-time control: A case study with periodic countercurrent chromatography and continuous virus inactivation.

Integrated continuous downstream processes with process analytical technology offer a promising opportunity to reduce production costs and increase process flexibility and adaptability. In this case study, an integrated continuous process was used to purify a recombinant protein on laboratory scale in a two-system setup that can be used as a general downstream setup offering multiproduct and multipurpose manufacturing capabilities. The process consisted of continuous solvent/detergent virus inactivation followed by periodic countercurrent chromatography in the capture step, and a final chromatographic polishing step. A real-time controller was implemented to ensure stable operation by adapting the downstream process to external changes. A concentration disturbance was introduced to test the controller. After the disturbance was applied, the product output recovered within 6 h, showing the effectiveness of the controller. In a comparison of the process with and without the controller, the product output per cycle increased by 27%, the resin utilization increased from 71.4% to 87.9%, and the specific buffer consumption was decreased by 21% with the controller, while maintaining a similar yield and purity as in the process without the disturbance. In addition, the integrated continuous process outperformed the batch process, increasing the productivity by 95% and the yield by 28%.

Model-assisted approaches for continuous chromatography: Current situation and challenges

Continuous bioprocessing is a promising trend in biopharmaceutical production, and multi-column continuous chromatography shows advantages of high productivity, high resin capacity utilization, small footprint, low buffer consumption and less waste. Due to the complexity and dynamic nature of continuous processing, traditional experiment-based approaches are often time-consuming and inefficient. In this review, model-assisted approaches were focused and their applications in continuous chromatography process development, validation and control were discussed. Chromatographic models are useful in describing particular process performances of continuous capture and polishing with multi-column chromatography. Model-assisted tools showed powerful ability in evaluating multiple operating parameters and identifying optimal points over the entire design space. The residence time distribution models, model-assisted process analytical technologies and model-predictive control strategies were also developed to reveal the propagation of disturbances, enhance real time monitor and achieve adaptive control to match the transient disturbances and deviations of continuous processes. Moreover, artificial neural networks and machine learning concepts were integrated into modeling approaches to improve data treatment. In general, further development in research and applications of model-assisted approaches for continuous chromatography are needed urgently to support the continuous manufacturing.

All-mode Automatic Temperature Control System for Superheated Industrial Steam Boiler during Buffer Consumption of Gaseous Production Waste

The matter of the efficiency increase for an industrial steam boiler during the blast furnace gas buffer consumption is considered.. When transferring to the mode with the bigger part of the blast furnace gas (in relation to the natural gas) the superheated steam temperature significantly increases because of high blast furnace gas flows and flame movement. The ordinary range of injection change is not enough for the steam temperature stabilization behind the convective superheater second stage CSS2. There is a well-known solution of this problem for drum steam boiler E220-100 (220 t/h, 10 MPa, 540°C), for the solution a combined system is used, which, in addition to the traditional regulator of the steam temperature behind the CSS2 acting upon the injection, has a steam temperature regulator behind the CSS1 acting upon the flame position by means of turning burner air-control registers. Although the system performance was considered only for one steam flow load (100%). This paper shows dependencies for parameters of the dynamical model of the superheated steam temperature regulating channel on the load in the range of 64-100%. In order to provide the all-mode performance of the system it is offered to make automatic adjustment of the regulators parameters as the function of the steam flow according to the dependencies where the process dynamic changes are taken into consideration.

Separating Empty and Full Recombinant Adeno-Associated Virus Particles Using Isocratic Anion Exchange Chromatography.

The development of recombinant adeno-associated virus (rAAV) gene therapies is becoming an increasing priority in the biotherapeutic landscape. One of the challenges associated with the production of rAAV is the formation of empty AAV particles that do not contain a therapeutic gene. The concerns about the impact of empty particles on clinical safety and rAAV-mediated gene expression have necessitated the development of purification processes to remove these species. The development of a robust and scalable purification process to separate empty and full AAV particles at large scale remains a challenge. In this study, a novel anion exchange chromatography process based on isocratic wash and elution steps to enrich full rAAV2 particles is presented. An operating design space is identified to ensure the robustness of the process. The isocratic chromatography provides several advantages over the traditional shallow linear gradient elution, including lower buffer consumption, smaller intermediate pool volumes, and more robust manufacturing.

Antibody capture with twin-column continuous chromatography: Effects of residence time, protein concentration and resin

The rapid development of the biopharmaceutical industry has gradually shifted the focus of R&D to integrated continuous manufacturing. In this study, the effects of residence time and protein concentration on the performance of twin-column periodic counter-current chromatography for continuous antibody capture with new affinity resin Praesto Jetted A50 were evaluated. The results showed that the continuous process exhibited better performance with higher productivity, higher capacity utilization and lower buffer consumption when compared with the batch process. Meanwhile, the increase of protein concentration could increase productivity, while it showed minor impact on capacity utilization and buffer consumption. Furthermore, monoclonal antibody (mAb) continuous capture from clarified cell culture supernatant was investigated. The results showed that the qualities of the products obtained from the continuous and batch processes were similar. The performance of the continuous capture process at 1 min residence time was significantly better than the batch process with the improvements in productivity (37.5 g/L/h) and capacity utilization (77.8%) as well as reducing buffer consumption by 60%. Finally, effects of Protein A resins on the continuous process were discussed, and the results indicated that the Protein A resins with higher dynamic binding capacity at low residence time would be more suitable for continuous processes. In general, continuous capture under the suitable operation conditions shows good performance and has great potential for mAb production.

Model-based process development and evaluation of twin-column continuous capture processes with Protein A affinity resin

Multi-column continuous chromatography has advantages of high resin capacity utilization and productivity, low buffer consumption and small footprint. Experimental optimization is often time-consuming and inefficient due to the complexity of continuous processes. In this study, a model-based approach was investigated to improve process development of twin-column continuous capture with Protein A affinity resin MabSelect PrismA. Breakthrough curves under various conditions, productivity and capacity utilization (CU) of the continuous processes under varying operating conditions were predicted. Effects of three key operating parameters (feed concentration (c0), interconnected feed residence time (RT) and breakthrough percentage control of the first column during interconnected feeding (s)) on the productivity and CU were evaluated. A recommended working window can be determined directly from contour maps to balance the trade-off between productivity and CU. The model-optimized operating conditions at varying feed concentrations were verified by experiments, which indicated that the model-based approach was feasible and reliable. The results showed that the suitable RT was 1~2 min and suitable s was 0.6~0.75 for the continuous IgG capture with MabSelect PrismA. The maximum productivity varied from 14 to 47 g/L/h with the feed IgG concentrations at the range of 1 to 10 mg/mL. The results indicated that model-based approach could assist process development efficiently and promote target-orientated process design for continuous processes.

A heuristic buffer sizing algorithm for implementing a renewable energy project

The swiftly growing wind farm projects together with the increasing uncertainty of these types of construction projects makes it more probable that projects will face delay. This research aims to introduce a heuristic algorithm to determine the sizes of project buffer and feeding buffers as well as dynamically control buffer consumption, named as Fuzzy Overlapping Buffer Management Algorithm (FOBMA). In this paper, the pentagonal fuzzy numbers were used to determine the appropriate amount of project activity resources. Also, an overlapping method was applied to obtain more realist activity durations. The FOBMA algorithm was compared to other algorithms using the data of 15 real-world wind farm projects as well as 15 randomly generated numerical examples. Moreover, the sensitivity analysis was conducted to validate the performance of the proposed algorithm. The findings demonstrate that the proposed FOBMA algorithm outperforms the other algorithms and yielded more realistic and shorter project duration.

A project buffer and resource management model in energy sector; a case study in construction of a wind farm project

PurposeThis study aims to introduce an efficient project buffer and resource management (PBRM) model for project resource leveling and project buffer sizing and controlling of project buffer consumption of a wind power plant project to achieve a more realistic project duration.Design/methodology/approachThe methodology of this research consists of three main phases. In the first phase of the research methodology, resource leveling is done in the project and resource conflicts of activities are identified. In the second phase, the project critical chain is determined, and the appropriate size of the project buffer is specified. In the third phase of the methodology, buffer consumption is controlled and monitored during the project implementation. After using the PBRM method, the results of this project were compared with those of the previous projects.FindingsAccording to the obtained results, it can be concluded that using PBRM model in this wind turbine project construction, the project duration became 25 per cent shorter than the scheduled duration and also 29 per cent shorter than average duration of previous similar projects.Research limitations/implicationsOne of the major problems with projects is that they are not completed according to schedule, and this creates time delays and losses in the implementation of projects. Today, as projects in the energy sector, especially renewable projects, are on the increase and also we are facing resource constraint in the implementation of projects, using scheduling techniques to minimize delays and obtain more realistic project duration is necessary.Practical implicationsThis research was carried out in a wind farm project. In spite of the initial plan duration of 142 days and average duration of previous similar projects of 146 days, the project was completed in 113 days.Originality/valueThis paper introduces a practical project buffer and resource management model for project resource leveling, project buffer sizing and buffer consumption monitoring to reach a more realistic schedule in energy sector. This study adds to the literature by proposing the PBRM model in renewable energy sector.

Scheduling evaluation in construction projects using the critical chain project management method

PT. A is a company engaged in construction, EPC (Engineering, Procurement and Construction), infrastructure investment, property and real estate. The case study that was raised in this study was the construction project of the retaining wall and the ABC dock that was carried out by PT. A. The problem in the project is that the project scheduling is not good, causing delays in project completion. The purpose of this research is to evaluate the scheduling of the project so that the optimum schedule can be obtained in project implementation. The method used in this study is Critical Chain Project Management (CCPM). CCPM is a project scheduling method that can optimize the schedule due to the absence of multitasking. The CCPM begins by estimating the time without safeguarding the existing time on each job by using the Cut & Paste Method. The critical path serves to find out the critical or non-critical work or activity. Critical activities on wall construction projects anchoring land and ABC dock namely work keep directors. Based on buffer consumption monitoring indicators due to the potential for the emergence of waste will end in use of project buffer duration consumed during the 19-35 period day and immediately take action if the buffer is consumed in the period of 36-53 days. Based on evaluation with critical application Project chain management obtained one feeding 4-day buffer and duration of the buffer project 53 days with the existing scheduling period 432 days to 379 days without buffer consumption.

Controlling the Superheated Steam Temperature during Buffer Consumption of Gaseous Production Waste through Adjusting the Injection and Flame Position

The article considers the possibility of achieving more efficient performance of a TP-13B industrial steam boiler fitted with a spray desuperheater and operating in the mode of buffer consumption of blast-furnace gas as applied to the superheated steam temperature automatic closed-loop control system. The main problem stems from the fact that the superheated steam temperature increases essentially due to large blast-furnace gas flowrates and displacement of the flame when shifting to operation with a large fraction of blast-furnace gas (with respect to the natural gas fraction). The usual injection adjustment range turns out to be insufficient for stabilizing the steam temperature downstream of the second-stage convection steam superheater (CSS2). In addition, the steam temperature downstream of the first-stage convection steam superheater (CSS1) increases significantly, because this section is not protected by injections. For solving the problem, it is proposed to use a combined system, which uses, in addition to the conventional steam temperature controller downstream of the CSS2, which adjusts the injection, a controller of steam temperature downstream of the CSS1, which adjusts the flame position by turning the air-control registers. With the steam temperature downstream of the CSS1 stabilized by adjusting the air-control registers, it becomes possible to pose less demanding requirements to the injections; in addition, with such stabilization, the CSS1 metal is protected from overheating. This is an advantage in comparison with the well-known arrangement in which such control is only performed when the injection valve position approaches the specified limit values. The functional and structural diagrams of the proposed control system are given. The parameters of the plant model channels’ transfer functions are determined proceeding from the known experimental data for the TP-13B boiler. The system has been studied by carrying out computations in the environment of the MathCad software system and the MatLab/Simulink modular simulation software package. The simulation model includes nonlinearities typical for the automation equipment used in thermal power engineering. The effectiveness of the proposed combined control system during operation with essential variations of the blast-furnace gas flowrate has been demonstrated. The information presented in the article can be used in fitting the industrial steam boilers operating with buffer consumption of gaseous production waste with means for automatic control of superheated steam temperature.

Process intensification by frontal chromatography: Performance comparison of resin and membrane adsorber for monovalent antibody aggregate removal.

Aggregates are amongst the most important product-related impurities to be removed during the downstream processing of antibodies due to their potential immunogenicity. Traditional operations use cation-exchange resins in bind-elute mode for their separation. However, frontal analysis is emerging as an alternative. In this study, a three-step process development for a membrane adsorber and a resin material is carried out, allowing the comparison between the stationary phases. Based on a screening study, optimal loading conditions are determined, which show that weak binding is favored on the membrane and strong binding on the resin. Transfer of these findings to breakthrough experiments shows that at 99% pool purity the yield is higher for the membrane, while the resin can be loaded twice as high, exceeding yields of 85%. For the investigated antibody and based on a given regeneration protocol, the productivity of the two phases is similar, ranging around 200 g/(L·h). Due to the higher loading, the resin requires about one-third less buffer than the membrane. Furthermore, the implementation of a wash step after loading allows to further increase yield by about 5%. In comparison to a generic bind-elute process, productivity and buffer consumption are improved by an order of magnitude.

Improved protein A resin for antibody capture in a continuous countercurrent tangential chromatography system.

Continuous countercurrent tangential chromatography (CCTC) enables steady-state continuous bioprocessing with low-pressure operation and high productivity. CCTC has been applied to initial capture of monoclonal antibodies (mAb) from clarified cell culture harvest and postcapture polishing of mAb; however, these studies were performed with commercial chromatography resins designed for conventional column chromatography. In this study, a small particle size prototype agarose resin (20-25 µm) with lower cross-linking was co-developed with industrial partner Purolite and tested with CCTC. Due to increased binding capacity and faster kinetics, the resulting CCTC process showed more than a 2X increase in productivity, and a 2X reduction in buffer consumption over commercial protein A resins used in previous CCTC studies, as well as more than a 10X productivity increase versus conventional column operation. Single-pass tangential flow filtration was integrated with the CCTC system, enabling simple control of eluate concentration. A scale-up exercise was conducted to provide a quantitative comparison of CCTC and batch column chromatography. These results clearly demonstrate opportunities for using otherwise unpackable soft small particle size resins with CCTC as the core of a continuous bioprocessing platform.