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The Use of Signal Filtering Algorithms in Bioreactor Characterisation and Monitoring Using Raman Spectroscopy

by Giuseppe Elia, Dylan Jones, Matthew Harding, and Chris Whitmore
Volume 14, Issue 3 (Fall 2015)

Raman spectroscopy offers an attractive solution for monitoring key process parameters and predictive modelling in cell culture processes using transgenic Chinese hamster ovary (CHO) cells. Frequent in-line measurements offer the potential for advanced control strategies. However, an erroneous value created by analytical signal noise is a significant issue that can affect process controls negatively. One such challenge is to differentiate the signal reflecting process changes, ranging from random to gross error, in a timely manner so the process control system can respond to these changes and maintain adequate control. The frequency of measurement acquisition in Raman monitoring makes signal filtering a viable solution to the problem of erroneous measurements. In this study, partial least squares (PLS) models were developed for multiple process parameters (such as glucose, glutamate, and viable cell density) using data from a 10 L bioreactor. The PLS models were applied to over 10,000 spectra taken at approximately five-minute intervals. Signal filters were applied to clean the resulting prediction data. The resulting predictions showed far fewer fluctuations from random errors, as well as greater resistance to gross (malfunction-based) errors, than the non-filtered prediction data. Effective signal filtering could represent a major improvement in the reliability of in-line spectroscopic monitoring of bioreactor processes and greatly improve the potential for robust control strategies on those processes...

Citation:
Elia G, Jones D, Harding M, Whitmore C. The use of signal filtering algorithms in bioreactor characterisation and monitoring using Raman spectroscopy. BioProcess J, 2015; 14(3): 34–43. http://dx.doi.org/10.12665/J143.Elia.

Posted online October 9, 2015.

 
The Development of a Flow-Through Mode Cation Exchange Process for the Purification of a Monoclonal Antibody

by Rachel B. Wollacott, PhD, Lauren E. Roth, PhD, Tracy L. Sears, Rebecca A. Sharpe, Monica Jiang, and Sadettin S. Ozturk, PhD
Volume 14, Issue 2 (Summer 2015)

Cation exchange chromatography is typically utilized in bind-and-elute mode for monoclonal antibody purification. However, during purification process development for a novel monoclonal antibody (MAb) intended for clinical use, it was determined that bind-and-elute conditions were not sufficient for removing significant levels of antibody aggregate. Based on preliminary purification data, an alternative purification method, operation of the cation exchange process in flow-through mode, was investigated. Flow-through mode cation exchange conditions were optimized by design of experiments. Optimal conditions resulted in <1% dimer and >85% recovery at all scales evaluated. An additional anion exchange polishing step was required to remove residual process impurities. The possibility of using the flow-through mode, cation exchange approach as a platform process, as well as the benefits and drawbacks of operating the cation exchange process in flow-through mode for MAb purification are discussed...

Citation:
Wollacott RB, Roth LE, Sears TL, Sharpe RA, Jiang M, Ozturk SS. The development of a flow-through mode cation exchange process for the purification of a monoclonal antibody. BioProcess J, 2015; 14(2): 5–13. http://dx.doi.org/10.12665/J142.Wollacott.

Posted online July 10, 2015.

 
Evaluation of Disinfection Procedures for Control of Potential Contamination of Biologicals

by Kathryn Martin Remington, PhD and Marian L. McKee, PhD
Volume 14, Issue 2 (Summer 2015)

An effective disinfection program is an essential component of a pharmaceutical/biopharmaceutical manufacturer’s contamination control strategy. A good disinfection program can help prevent microbial or viral contamination of the manufactured product, further ensuring product safety for patients. The term disinfection is often used interchangeably with cleaning, but the purpose of disinfection is quite different from that of cleaning. Disinfection of a surface will result in inactivation of infectious agents such as bacteria, fungi, and viruses, whereas cleaning a surface removes soil, debris, and other residues. A dirty surface that contains soil or cleaner/disinfectant residues can complicate disinfection or even contain infectious agents, yet a visibly clean surface may still require disinfection. Cleaning and disinfection programs complement each other. In contrast to a cleaning procedure, the effectiveness of a disinfection procedure is dependent on factors such as the type of disinfectant used, the application method, and contact time...

Citation:
Remington KM, McKee ML. Evaluation of disinfection procedures for control of potential contamination of biologicals. BioProcess J, 2015; 14(2): 14–21. http://dx.doi.org/10.12665/J142.Remington.

Posted online July 10, 2015.

 
Analysis of Downstream Process Controls to Assure the Quality of Recombinant Granulocyte-Colony Stimulating Factor

by Natacha Pérez, Mónica Navarro, Lázaro Estenoz, Ernesto Urrutia, Denis Alvarez, Oscar Cruz, Yunaisy Jiménez, Yodelis Calvo, Regla Somoza, Neyda Hernández, Lázaro Betancourt, and Rodolfo Valdés
Volume 14, Issue 2 (Summer 2015)

Human granulocyte colony-stimulating factor (GCSF) is produced by biotech laboratories and production facilities for reducing neutropenia duration and sequels in patients with myelosuppressor treatments, among other applications. However, real challenges for these laboratories started in 2015 when the PEGylated-GCSF patent expired, opening alternatives for developing biomanufacturing processes and new applications. Thus, the purpose of this study was to analyze downstream process controls designed to ensure recombinant human GCSF (rh-GCSF) quality and to provide some evidence of the downstream process validation status. Study outcomes proved that the rh-GCSF expression system was stable and chromatographic profiles were reproducible among samples. Also, rh-GCSF purity determination demonstrated an increased purity, step-by-step, reaching maximum value after ion exchange chromatography. The rh-GCSF characterization by mass spectrometry, biological and specific activity, immunodetermination, isoelectrofocusing, sterility, endotoxin level, host cell protein, and DNA content also showed high rh-GCSF molecular integrity and purity. Therefore, rh-GCSF quality was demonstrated, and the purification process was consistent for rh-GCSF industrial production...

Citation:
Pérez N, Navarro M, Estenoz L, Urrutia E, Alvarez D, Cruz O et al. Analysis of downstream process controls to assure the quality of recombinant granulocyte-colony stimulating factor. BioProcess J, 2015; 14(2): 39–48. http://dx.doi.org/10.12665/J142.Valdes.

Posted online July 10, 2015.

 
Achieving MAb Binding Greater Than 120 mg/mL With Novel, High-Flow Agarose Ion Exchange Resins

by Hans J. Johansson, Hans Berg, Patrick Gilbert, Mark Hicks, Serguei Kosvintsev, and Charlotte Vassay-Jones
Volume 14, Issue 2 (Summer 2015)

Agarose-based chromatography beads were first introduced by Stellan Hjertén in 1962. Fifty years later, beaded agarose has become the dominant resin for protein purification and is extensively used, ranging from research-scale in sub mL volumes to full-scale manufacturing in > 500 L chromatography columns. Recent resin development work has focused on increasing capacity and selectivity through different grafting technologies and ligand developments. Purolite is using new technologies to develop beaded agarose with particle sizes from 40–100 μm with improved pressure flow properties and a porosity structure optimized for protein chromatography. Our work shows that it is possible to design and produce homogeneous agarose resins for large-scale manufacturing, with significantly improved pressure/flow properties, capacity, and resolution compared to what is commercially available today. A set of novel agarose-based ion exchangers have been characterized, and initial application data is available...

Citation:
Johansson HJ, Berg H, Gilbert P, Hicks M, Kosvintsev S, Vassay-Jones C. Achieving MAb binding greater than 120 mg/mL with novel, high-flow agarose ion exchange resins. BioProcess J, 2015; 14(2): 33–6. http://dx.doi.org/10.12665/J142.Johansson.

Posted online July 10, 2015.

 
Preparing Biotherapeutic Extracellular Vesicles: Ultrafilters, Mesenchymal Stem Cells, and the Regulatory Horizon

by Chandreyee Das, PhD
Volume 14, Issue 2 (Summer 2015)

Extracellular vesicles (EVs) are particles of varying size, structure, and composition, which are secreted from cells and frequently mediate intercellular communication. Because they have been shown to travel through the circulatory system and also through biological barriers to deliver their molecular contents to distant target cells, there has been growing interest in using EVs, such as exosomes, as drug delivery vehicles. In the past ten years, the number of published articles linking EVs to drug delivery has increased 20-fold. EVs are being engineered to deliver protein, RNA, and small molecule cargo to target cells, tissues, and entire systems. Also, EVs derived from certain cells show inherent, therapeutically beneficial activity. For example, EVs prepared from antigen-presenting cells can be used like vaccines to elicit a desired immune response from a host. The idea of using lipid-based carriers to deliver drugs is, of course, not new. Liposomes were first introduced as delivery vehicles in the 1960s, and some liposome-formulated drugs have made it to market. However, developers of liposome-based therapies are still trying to overcome the challenges of particle clearance by the immune system, immunogenicity, and the lack of specificity in targeting these particles to particular cell types. From this perspective, EVs are an attractive alternative to synthetic liposomes. They have already demonstrated stability in the circulatory system, and because of the proteins embedded in EV membranes, they reach target cells and are taken up more efficiently...

Citation:
Das C. Preparing biotherapeutic extracellular vesicles: ultrafilters, mesenchymal stem cells, and the regulatory horizon. BioProcess J, 2015; 14(2): 50–3. http://dx.doi.org/10.12665/J142.Das.

Posted online July 10, 2015.

 
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