Drug Substance Manufacturing Research Articles

From chemostats to high‐density perfusion: the progression of continuous mammalian cell cultivation

AbstractContinuous cultivation of mammalian cells originated in chemostats in the 1950s and, through a series of technological advancements, has evolved into modern‐day high‐density perfusion processes with volumetric productivities >5 g L–1 day–1over extended cultivation periods. With appropriate process development, these productivities can be achieved with no adverse impact on cell line stability and product quality. Developments in downstream processing and automation have enabled the integration of drug substance manufacturing processes suitable for next‐generation plants that require lower capital deployment, with the potential for rapid construction and validation for clinical and commercial production. Perfusion also has been successfully used to generate high‐density cell banks (> 50 × 106cells mL–1) and for seed‐train optimization. They have resulted in significant productivity increases (10‐fold increase in volumetric productivity) from fed‐batch bioreactors by providing a high‐density seeding culture that elevates the inoculation density in a production bioreactor (> 5 × 106cells mL–1). Related advancements in cell culture medium formulations and cell line performance typically are independent of bioreactor format and have broad applicability for biotherapeutic manufacturing. The last decade has seen renewed interest in high‐density perfusion cultures and technological advances spanning the entire space of drug substance manufacturing – from cell line development to the final purification step. Continually evolving, these new technologies now are being introduced into clinical and commercial manufacturing. We anticipate that the general principles and knowledge gleaned from process intensification will extend well beyond classical perfusion cultivation and into all aspects of mammalian cell culture. © 2021 Society of Chemical Industry (SCI).

Analytical Method Development and Validation of Glipizide to Determine Residual solvents by head Space-Gas Chromatography

Residual solvents in Pharmaceuticals are termed as organic volatile impurities. These are the chemicals that are used in the manufacture of drug substance or excipients or use in the preparation of final formulation. Most of the available methods use liquid chromatography which could be expensive and time consuming. Hence, an analytical methodology was developed for the quantification of residual solvents in Glipizide using a headspace gas chromatography (HSGC) with the help of flame ionization detector (FID). Methanol, acetone and dimethyl formamide as residual solvents were determined in Glipizide. Analysis was performed by headspace GC/FID method on Auto system- HS40. Nitrogen was used as a carrier gas and the separation of residual solvents was achieved by DB-Wax 0.25mm, 0.3mcm column. The thermostat temperature was 115 °C for 40 minutes for each vial. % RSD for nine injections obtained are in acceptance criteria. The correlation coefficient R2 obtained greater than 0.99. The method parameters were validated includes specificity, limit of detection and quantification, accuracy, linearity, precision, and robustness. According to the International Conference on Harmonization (ICH) guidelines, a new simple, specific, accurate and precise method was developed and validated.

Process and operations strategies to enable global access to antibody therapies.

Few monoclonal antibodies are currently approved for treating infectious diseases, but multiple products are in development against a broad range of infectious diseases, including Ebola, influenza, hepatitis B, HIV, dengue, and COVID-19. The maturity of mAb technologies now allow us to identify and advance neutralizing mAb products to the clinic at "pandemic pace", as the pipeline of mAbs targeting SARS-CoV-2 has demonstrated. Ensuring global access to these products for passive immunization, however, will require both low manufacturing cost and multi-ton production capacity-particularly for those infectious diseases where the geographic burden falls mostly in low- and middle-income countries or those with pandemic potential. Analysis of process economics and manufacturing technologies for antibody and other parenteral protein therapeutics demonstrates the importance of economies of scale to reducing the cost of goods for drug substance manufacturing. There are major benefits to convergence on a standardized platform process for antibody production that is portable to most existing very large-scale facilities, carries low risk for complications during process transfer and scale-up, and has a predictable timeline and probability of technical and regulatory success. In the case of an infectious disease with pandemic potential which could be treated with an antibody, such as COVID-19 or influenza, these advantages are paramount.

Considerations for Implementation of a New Drug Substance Container for Subzero Storage

Therapeutic manufacturing has become globalized in recent decades, necessitating transportation of drug substance across the world. The outcome of this expansion is significant costs for shipment and added risk of damage to the drug substance containers. There are multiple container options with various materials of construction for storage of Biologics drug substance (DS). This study evaluates a newly designed CryoVault™ container and previously characterized CelsiusPak® bag container using a well-represented scale-down model. Consideration of an appropriate storage container includes the risk assessment of the design and material of construction, which can potentially impact product quality attributes, stability and container leachables. An extensive data package, including product stability over time and temperature with respect to impact of extractables and leachables from different containers undergoing a typical one freeze/thaw cycle process was evaluated. This drove to the decision for implementation of a container into the drug substance manufacturing process.

Development of a Quality Risk Based Tool for the Selection of Regulatory Starting Materials for Commercial Drug Substance Manufacturing Processes

The selection of regulatory starting materials (RSMs) is a critical step in determining where the drug substance manufacturing process begins as it relates to the submission and approval of the com...

An Overview of Drug Substance Manufacturing Processes.

To develop a comprehensive understanding of pharmaceutical drug substance manufacturing (DSM) processes, we conducted a data mining study to examine 50 new drug applications (NDAs) approved in 2010-2016. We analyzed the prevalence of several frequently deployed in-process control (IPC) techniques and postreaction workup procedures, as well as the operational conditions specified for reactions and workups. Our findings show that crystallization and high-performance liquid chromatography (HPLC) were the most commonly used workup steps and in-process controls, respectively, in drug substance manufacturing. On average, each NDA implemented 12.6 in-process controls and 11.3 workups. Operation time for reactions and workup procedures varied from a few minutes to multiple days, though 61% of these were between 1 and 10h.

Effective Control of Crystal Size via an Integrated Crystallization, Wet Milling, and Annealing Recirculation System

For drug substance manufacturing, it is necessary to have a robust crystallization process that can isolate quality active pharmaceutical ingredients with the desired crystal size distribution (CSD...

Strategies for high-concentration drug substance manufacturing to facilitate subcutaneous administration: A review.

To achieve the high protein concentrations required for subcutaneous administration of biologic therapeutics, numerous manufacturing process challenges are often encountered. From an operational perspective, high protein concentrations result in highly viscous solutions, which can cause pressure increases during ultrafiltration. This can also lead to low flux during ultrafiltration and sterile filtration, resulting in long processing times. In addition, there is a greater risk of product loss from the hold-up volumes during filtration operations. From a formulation perspective, higher protein concentrations present the risk of higher aggregation rates as the closer proximity of the constituent species results in stronger attractive intermolecular interactions and higher frequency of self-association events. There are also challenges in achieving pH and excipient concentration targets in the ultrafiltration/diafiltration (UF/DF) step due to volume exclusion and Donnan equilibrium effects, which are exacerbated at higher protein concentrations. This paper highlights strategies to address these challenges, including the use of viscosity-lowering excipients, appropriate selection of UF/DF cassettes with modified membranes and/or improved flow channel design, and increased understanding of pH and excipient behavior during UF/DF. Additional considerations for high-concentration drug substance manufacturing, such as appearance attributes, stability, and freezing and handling are also discussed. These strategies can be employed to overcome the manufacturing process challenges and streamline process development efforts for high-concentration drug substance manufacturing.

Knowledge Management as a Pharmaceutical Quality System Enabler: How Enhanced Knowledge Transfer Can Help Close the ICH Q10 to ICH Q12 Gap.

Knowledge management (KM) is identified in ICH Q10 (Pharmaceutical Quality System), as a key enabler to the pharmaceutical quality system (PQS). ICH Q8 (Pharmaceutical Development), ICH Q11 (Development and Manufacture of Drug Substances), and ICH Q12 (Technical and Regulatory Considerations for Pharmaceutical Product Lifecycle Management) each build on the expectation that knowledge will be managed effectively in order to support and improve the product and process across the pharmaceutical product life cycle. However, in spite of the fact that KM was introduced in ICH Q10 over 10 years ago, there is ample evidence that it is not yet a mature discipline within the biopharmaceutical sector, and the authors suggest that this could hinder full realization of the potential benefits of ICH Q8, ICH Q11, and ICH Q12. The Pharmaceutical Regulatory Science Team (PRST), a research team based at the Dublin Technological University (TU Dublin) in Ireland, has been conducting research on KM for several years, and this paper presents the next phase in this research. Specifically, the focus of this current research was to explore ways to offer practical solutions to improve the management of knowledge across the pharmaceutical product life cycle, starting with a focus on enhancing knowledge transfer during technology transfer projects. The typical challenges associated with ineffective knowledge transfer were presented and the high-level requirements needed to address these were identified through the research. From these requirements, a four-step framework was developed as a systematic means to enhance knowledge transfer. Accompanying the framework was a KM toolkit consisting of a range of KM practices (tools, processes, and behaviors) to facilitate more effective knowledge flow during technology transfer. It was then illustrated how such a framework can be extended across the entire pharmaceutical product life cycle, supporting the advancement of KM from an enabler in ICH Q10 to a key consideration (both technical and regulatory) in ICH Q12.

Recent Advances in Co-processed APIs and Proposals for Enabling Commercialization of These Transformative Technologies

Optimized physical properties (e.g., bulk, surface/interfacial, and mechanical properties) of active pharmaceutical ingredients (APIs) are key to the successful integration of drug substance and drug product manufacturing, robust drug product manufacturing operations, and ultimately to attaining consistent drug product critical quality attributes. However, an appreciable number of APIs have physical properties that cannot be managed via routes such as form selection, adjustments to the crystallization process parameters, or milling. Approaches to control physical properties in innovative ways offer the possibility of providing additional and unique opportunities to control API physical properties for both batch and continuous drug product manufacturing, ultimately resulting in simplified and more robust pharmaceutical manufacturing processes. Specifically, diverse opportunities to significantly enhance API physical properties are created if allowances are made for generating co-processed APIs by introducing nonactive components (e.g., excipients, additives, carriers) during drug substance manufacturing. The addition of a nonactive coformer during drug substance manufacturing is currently an accepted approach for cocrystals, and it would be beneficial if a similar allowance could be made for other nonactive components with the ability to modify the physical properties of the API. In many cases, co-processed APIs could enable continuous direct compression for small molecules, and longer term, this approach could be leveraged to simplify continuous end-to-end drug substance to drug product manufacturing processes for both small and large molecules. As with any novel technology, the regulatory expectations for co-processed APIs are not yet clearly defined, and this creates challenges for commercial implementation of these technologies by the pharmaceutical industry. The intent of this paper is to highlight the opportunities and growing interest in realizing the benefits of co-processed APIs, exemplified by a body of academic research and industrial examples. This work will highlight reasons why co-processed APIs would best be considered as drug substances from a regulatory perspective and emphasize the areas where regulatory strategies need to be established to allow for commercialization of innovative approaches in this area.

Determining the Clearance of Degraded Protein via a Monoclonal Antibody Purification Process in Support of Cleaning Carryover Limits in Multiproduct Facilities

Cleaning validation acceptance criteria in multiproduct facilities are established using maximum allowable carryover calculations. Carryover calculations incorporate the shared equipment surface area between two products to ensure that an acceptable limit for residue from the previously manufactured product to the subsequent product is determined. The shared surface area can be limited to areas where carryover presents the highest risk to product quality or patient safety. In these cases, specifically for biologic drug substance manufacturing, the shared surface area is limited to equipment after the purification process based on the assumption that the purification process would remove potential product fragment residues from the previous product. Until now, this assumption has been based on empirical knowledge without experimental data quantifying the clearance or removal of potential residues. We present a three-part study that determined the effects of cleaning conditions on selected monoclonal antibodies (mAbs) and the generation of degraded fragments and evaluated the clearance of both the degraded mAb1 in a laboratory setting and the degraded fragments in the presence of a subsequent product, assessing the risk of co-purification. Several analytical techniques were used, including gel electrophoresis, capillary zone electrophoresis/laser-induced florescence detection, and liquid chromatography-mass spectrometry. Protein fragment generation was demonstrated for five different mAbs from different immunoglobulin G subclasses. The clearance of the degraded fragments in the absence and presence of the subsequent product was demonstrated by calculating fold clearance and log reduction value (LRV) for each chromatography step. The data showed that the fragments generated during cleaning could be removed by the purification process. The fold clearances were determined to be values of 5400 (3.7 LRV) in the absence of subsequent product and 4428 (3.6 LRV) in the presence of subsequent product. The results supported the removal of product residues from shared surface areas by the purification process in multiproduct biologic drug substance manufacturing facilities.

Control Strategy Approach for a Well-Characterized Vaccine Drug Product

Trumenba (MenB-FHbp; bivalent rLP2086), the first meningococcal serogroup B vaccine approved in the United States and subsequently approved in Europe, Canada, and Australia, is well-characterized. Pfizer devised a control strategy approach by using a simplified control strategy wheel for Trumenba based on International Council for Harmonisation (ICH) Q8 (R2), Q9, Q10, and Q11 guidelines, which provide complementary guidance on pharmaceutical development, quality risk management, quality systems, and development and manufacture of drug substances, respectively. These guidelines ensure product quality using a scientific and risk-based approach. Trumenba contains two factor H binding proteins (FHbps), one from each of the two FHbp subfamilies (A and B), adsorbed onto aluminum phosphate. Trumenba manufacturing processes are complicated by the recombinant protein expression of Subfamily A and B proteins and the nature of the drug product (suspension in syringes); the latter also introduces challenges in controlling product critical quality attributes during the development process. In such complex systems, the control strategy is critical to ensuring consistent desired product quality; it also supports the regulatory requirement of continued improvement through continuous process verification and aids regulatory filing. This article describes Pfizer's approach toward robust control strategy development, built on product and process understanding, and links control strategy to regulatory document sections and flow of controls. Specifically, an approach is presented on product quality attribute criticality determination based on safety and efficacy and on an understanding of process parameter criticality. This was achieved by studying the impact of the approach on product quality attributes to define process parameter and in-process controls. This approach is further explained through Trumenba case studies, highlighting specific quality attributes and the associated controls implemented, and provides a holistic view of controls employed for both drug substance and drug product.

Interfacial Stress in the Development of Biologics: Fundamental Understanding, Current Practice, and Future Perspective

Biologic products encounter various types of interfacial stress during development, manufacturing, and clinical administration. When proteins come in contact with vapor–liquid, solid–liquid, and liquid–liquid surfaces, these interfaces can significantly impact the protein drug product quality attributes, including formation of visible particles, subvisible particles, or soluble aggregates, or changes in target protein concentration due to adsorption of the molecule to various interfaces. Protein aggregation at interfaces is often accompanied by changes in conformation, as proteins modify their higher order structure in response to interfacial stresses such as hydrophobicity, charge, and mechanical stress. Formation of aggregates may elicit immunogenicity concerns; therefore, it is important to minimize opportunities for aggregation by performing a systematic evaluation of interfacial stress throughout the product development cycle and to develop appropriate mitigation strategies. The purpose of this white paper is to provide an understanding of protein interfacial stability, explore methods to understand interfacial behavior of proteins, then describe current industry approaches to address interfacial stability concerns. Specifically, we will discuss interfacial stresses to which proteins are exposed from drug substance manufacture through clinical administration, as well as the analytical techniques used to evaluate the resulting impact on the stability of the protein. A high-level mechanistic understanding of the relationship between interfacial stress and aggregation will be introduced, as well as some novel techniques for measuring and better understanding the interfacial behavior of proteins. Finally, some best practices in the evaluation and minimization of interfacial stress will be recommended.

A comparative study of continuous operation between a dynamic baffle crystallizer and a stirred tank crystallizer

Crystallization, often as the final isolation and purification step in drug substance manufacturing, has substantial impact on downstream efficiency and final drug product quality. It is a critical but challenging step in developing end-to-end continuous manufacturing, which has been identified as an emerging technology in the pharmaceutical manufacturing sector by the U.S. Food and Drug Administration (FDA). A traditional stirred tank crystallizer (STC) operated as a mixed-suspension-mixed-product-removal (MSMPR) system is a popular choice for continuous crystallization for its utilization of existing knowledge and equipment. However, there are disadvantages associated with agitational systems like the STC, such as poor local mixing and high shear rate. A commercial dynamic baffle crystallizer (DBC) was studied here as an alternative unit operation. The DBC in this study consists of a jacketed glass vessel with dynamic ‘donut’ shaped baffles to provide oscillatory mixing to improve heat and mass transfer while exerting less shear. Our goal is to compare continuous operation performances in the DBC with the STC as MSMPR systems. First, residence time distribution (RTD) studies of both systems were performed considering single phase (liquid only) and two-phase (solid-liquid) operation. The RTD gives good insights into the mixing dynamics without computationally heavy fluid dynamic simulations. Continuous cooling crystallization of paracetamol was performed in the DBC and the STC. The DBC showed good potential to be used as an MSMPR system producing more uniform RTDs as well as higher quality crystallization products compared to a traditional STC.

Generic anion-exchange chromatography method for analytical and preparative separation of nucleotides in the development and manufacture of drug substances

Nucleotides are among the most frequently used chemical building blocks in the research, development and manufacture of drug substances. They are composed of three highly polar subunit molecules (a nucleobase, a sugar, and at least one phosphate group), which makes their separation and analysis very challenging by conventional liquid chromatography techniques. Herein, we describe a simple, efficient, and cost-effective ion-exchange chromatography (IEC) method for the separation and purification of over 20 nucleotides. This method combines the use of a Tosoh TSKgel SuperQ-5P W resin in conjunction with a fully aqueous eluent profile (ammonium bicarbonate-based) that allows for a straightforward scale-up transition and convenient drying process with minimal environmental impact. This generic method was optimized using chromatography simulation software (ACD Labs/LC Simulator) and successfully applied to the preparative purification of multicomponent nucleotide mixtures using readily available Fast Protein Liquid Chromatography (FPLC) instrumentation. These IEC method conditions can be effectively applied as the starting point for method development and isolation of other highly polar nucleotide species beyond those investigated in this study.

A computational study on the stereoselective reduction of cyclic ketones by LiAl(OR)3H in THF

As part of the development of the ketone reduction step for the drug substance manufacturing process of VX-222, the mechanism for stereoselective reduction of model compound 4-tert-butylcyclohexanone by LiAlH(OMe)3 with explicit THF mono- and bissolvation was studied computationally with three DFT functionals (B3LYP, B3LYP-D3 and M06-2X). The calculations provide a detailed and quantitative description of the stepwise mechanism for this polarized reaction: CH bond formation followed by AlO bond formation.

Advances in industrial biopharmaceutical batch process monitoring: Machine-learning methods for small data problems.

Biopharmaceutical manufacturing comprises of multiple distinct processing steps that require effective and efficient monitoring of many variables simultaneously in real-time. The state-of-the-art real-time multivariate statistical batch process monitoring (BPM) platforms have been in use in recent years to ensure comprehensive monitoring is in place as a complementary tool for continued process verification to detect weak signals. This article addresses a longstanding, industry-wide problem in BPM, referred to as the "Low-N" problem, wherein a product has a limited production history. The current best industrial practice to address the Low-N problem is to switch from a multivariate to a univariate BPM, until sufficient product history is available to build and deploy a multivariate BPM platform. Every batch run without a robust multivariate BPM platform poses risk of not detecting potential weak signals developing in the process that might have an impact on process and product performance. In this article, we propose an approach to solve the Low-N problem by generating an arbitrarily large number of in silico batches through a combination of hardware exploitation and machine-learning methods. To the best of authors' knowledge, this is the first article to provide a solution to the Low-N problem in biopharmaceutical manufacturing using machine-learning methods. Several industrial case studies from bulk drug substance manufacturing are presented to demonstrate the efficacy of the proposed approach for BPM under various Low-N scenarios.

Raw material variability of an active pharmaceutical ingredient and its relevance for processability in secondary continuous pharmaceutical manufacturing

Active Pharmaceutical Ingredients (API) raw material variability is not always thoroughly considered during pharmaceutical process development, mainly due to low quantities of drug substance available. However, synthesis, crystallization routes and production sites evolve during product development and product life cycle leading to changes in physical material attributes which can potentially affect their processability. Recent literature highlights the need for a global approach to understand the link between material synthesis, material variability, process and product quality. The study described in this article aims at explaining the raw material variability of an API using extensive material characterization on a restricted number of representative batches using multivariate data analysis. It is part of a larger investigation trying to link the API drug substance manufacturing process, the resulting physical API raw material attributes and the drug product continuous manufacturing process. Eight API batches produced using different synthetic routes, crystallization, drying, delumping processes and processing equipment were characterized, extensively. Seventeen properties from seven characterization techniques were retained for further analysis using Principal Component Analysis (PCA). Three principal components (PCs) were sufficient to explain 92.9% of the API raw material variability. The first PC was related to crystal length, agglomerate size and fraction, flowability and electrostatic charging. The second PC was driven by the span of the particle size distribution and the agglomerates strength. The third PC was related to surface energy. Additionally, the PCA allowed to summarize the API batch-to-batch variability in only three PCs which can be used in future drug product development studies to quantitatively evaluate the impact of the API raw material variability upon the drug product process. The approach described in this article could be applied to any other compound which is prone to batch-to-batch variability.

COMMON DEFICIENCIES RAISED BY VARIOUS REGULATORY AGENCIES

Timely Product registration is a challenge in today’s scenario. Regulatory agencies are keen in assessing CTD sections like redefining starting material of Drug substance manufacturing, Pharmaceutical development, impurities in Drug substance and Drug product, Container-closure. Common deficiencies are presented in this article.

Supercritical fluid chromatography-photodiode array detection-electrospray ionization mass spectrometry as a framework for impurity fate mapping in the development and manufacture of drug substances

Impurity fate and purge studies are critical in order to establish an effective impurity control strategy for approval of the commercial filing application of new medicines. Reversed phase liquid chromatography-diode array-mass spectrometry (RPLC-DAD-MS) has traditionally been the preferred tool for impurity fate mapping. However, separation of some reaction mixtures by LC can be very problematic requiring combination LC-UV for area % analysis and a different LC-MS method for peak identification. In addition, some synthetic intermediates might be chemically susceptible to the aqueous conditions used in RPLC separations. In this study, the use of supercritical fluid chromatography-photodiode array-electrospray ionization mass spectrometry (SFC-PDA-ESIMS) for fate and purge of two specified impurities in the 1-uridine starting material from the synthesis of a bis-piv 2′keto-uridine, an intermediate in the synthesis of uprifosbuvir, a treatment under investigation for chronic hepatitis C infection. Readily available SFC instrumentation with a Chiralpak IC column (4.6 × 150 mm, 3 μm) and ethanol: carbon dioxide based mobile phase eluent enabled the separation of closely related components from complex reaction mixtures where RLPC failed to deliver optimal chromatographic performance. These results illustrate how SFC combined with PDA and ESI-MS detection can become a powerful tool for direct impurity fate mapping across multiple reaction steps.