Sterile Filtration of Highly Concentrated Protein Formulations: Impact of Protein Concentration, Formulation Composition, and Filter Material

Understanding adsorption behavior of Polysorbate-20 to sterile filters in therapeutic proteins final filtration process

Surfactants are commonly used in the therapeutic protein manufacturing process as stabilizer. Polysorbate-20 (PS-20) is one of the most commonly used surfactants to mitigate protein aggregation in the therapeutic protein formulation. It has been observed that polysorbate can be adsorbed by sterile filters during the final filtration process, which poses risk of uneven distribution and potentially reduced polysorbate concentration in final products. In this study, we evaluated the PS-20 adsorption behavior using commonly used sterilizing-grade microfiltration (MF) membranes via a customized filtration set-up. The effect of membrane properties, including the membrane materials, modification, and layer configuration were studied. In addition, the effect of PS-20 concentration was evaluated and the PS-20 adsorption amount by each type of membranes was determined quantitatively and showed good agreement with the in-process adsorption results. Finally, the selection of sterile filters and strategy of pre-flush are discussed for ensuring accurate PS-20 content in the final therapeutic protein drug product.

Shear stress as a driver of degradation for protein-based therapeutics: More accomplice than culprit

Protein degradation is a major concern for protein-based therapeutics. It may alter the biological activity of the product and raise the potential for undesirable effects on the patients. Among the numerous drivers of protein degradation, shear stress has been the focus around which much work has revolved since the 1970s. In the pharmaceutical realm, the product is often processed through several unit operations, which include mixing, pumping, filtration, filling, and atomization. Nonetheless, the drug might be exposed to significant shear stresses, which might cooperatively contribute to product degradation, together with interfacial stress. This review presents fundamentals of shear stress about protein structure, followed by an overview of the drivers of product degradation. The impact of shear stress on protein stability in different unit operations is then presented, and recommendations for limiting the adverse effects on the biopharmaceutical formulations are outlined. Finally, several devices used to explore the effects of shear stress are discussed.

In-situ biophysical characterization of high-concentration protein formulations using wNMR

High-concentration protein formulation is of paramount importance in patient-centric drug product development, but it also presents challenges due to the potential for enhanced aggregation and increased viscosity. The analysis of critical quality attributes often necessitates the transfer of samples from their primary containers together with sample dilution. Therefore, there is a demand for noninvasive, in situ biophysical methods to assess protein drug products directly in primary sterile containers, such as prefilled syringes, without dilution. In this study, we introduce a novel application of water proton nuclear magnetic resonance (wNMR) to evaluate the aggregation propensity of a high-concentration drug product, Dupixent® (dupilumab), under stress conditions. wNMR results demonstrate a concentration-dependent, reversible association of dupilumab in the commercial formulation, as well as irreversible aggregation when exposed to accelerated thermal stress, but gradually reversible aggregation when exposed to freeze and thaw cycles. Importantly, these results show a strong correlation with data obtained from established biophysical analytical tools widely used in the pharmaceutical industry. The application of wNMR represents a promising approach for in situ noninvasive analysis of high-concentration protein formulations directly in their primary containers, providing valuable insights for drug development and quality assessment.

Application of Formulation Principles to Stability Issues Encountered During Processing, Manufacturing, and Storage of Drug Substance and Drug Product Protein Therapeutics

The field of formulation and stabilization of protein therapeutics has become rather extensive. However, most of the focus has been on stabilization of the final drug product. Yet, proteins experience stress and degradation through the manufacturing process, starting with fermentaition. This review describes how formulation principles can be applied to stabilize biopharmaceutical proteins during bioprocessing and manufacturing, considering each unit operation involved in prepration of the drug substance. In addition, the impact of the container on stabilty is discussed as well.

The ice age - A review on formulation of Adeno-associated virus therapeutics

Gene therapies offer promising therapeutic alternatives for many disorders that currently lack efficient treatment options. Due to their chemical nature and physico-chemical properties, delivery of polynucleic acids into target cells and subcellular compartments remains a significant challenge. Adeno-associated viruses (AAV) have gained a lot of interest for the efficient delivery of therapeutic single-stranded DNA (ssDNA) genomes over the past decades. More than a hundred products have been tested in clinical settings and three products have received market authorization by the US FDA in recent years. A lot of effort is being made to generate potent recombinant AAV (rAAV) vectors that show favorable safety and immunogenicity profiles for either local or systemic administration. Manufacturing processes are gradually being optimized to deliver a consistently high product quality and to serve potential market needs beyond rare indications. In contrast to protein therapeutics, most rAAV products are still supplied as frozen liquids within rather simple formulation buffers to enable sufficient product shelf life, significantly hampering global distribution and access. In this review, we aim to outline the hurdles of rAAV drug product development and discuss critical formulation and composition aspects of rAAV products under clinical evaluation. Further, we highlight recent development efforts in order to achieve stable liquid or lyophilized products. This review therefore provides a comprehensive overview on current state-of-the-art rAAV formulations and can further serve as a map for rational formulation development activities in the future.

Drug delivery breakthrough technologies - A perspective on clinical and societal impact

The way a drug molecule is administered has always had a profound impact on people requiring medical interventions - from vaccine development to cancer therapeutics. In the Controlled Release Society Fall Symposium 2022, a trans-institutional group of scientists from industry, academia, and non-governmental organizations discussed what a breakthrough in the field of drug delivery constitutes. On the basis of these discussions, we classified drug delivery breakthrough technologies into three categories. In category 1, drug delivery systems enable treatment for new molecular entities per se, for instance by overcoming biological barriers. In category 2, drug delivery systems optimize efficacy and/or safety of an existing drug, for instance by directing distribution to their target tissue, by replacing toxic excipients, or by changing the dosing reqimen. In category 3, drug delivery systems improve global access by fostering use in low-resource settings, for instance by facilitating drug administration outside of a controlled health care institutional setting. We recognize that certain breakthroughs can be classified in more than one category. It was concluded that in order to create a true breakthrough technology, multidisciplinary collaboration is mandated to move from pure technical inventions to true innovations addressing key current and emerging unmet health care needs.

Multi-Detection Size Exclusion Chromatography as an Advanced Tool for Monitoring Enzyme-Antibody Conjugation Reaction and Quality Control of a Final Product

The multi-detection size exclusion chromatography (SEC) has been recognized as an advanced analytical technique for the characterization of macromolecules and process control, as well as the manufacturing and formulation of biotechnology products. It reveals reproducible molecular characterization data, such as molecular weight and its distribution, and the size, shape, and composition of the sample peaks. The aim of this work was to investigate the potential and suitability of the multi-detection SEC as a tool for surveillance over the molecular processes during the conjugation reaction between the antibody (IgG) and horseradish peroxidase (HRP), and demonstrate the plausibility of its application in the quality control of the final product, the IgG-HRP conjugate. Guinea pig anti-Vero IgG-HRP conjugate was prepared using a modified periodate oxidation method, based on periodate oxidation of the carbohydrate side chains of HRP, followed by the formation of Schiff bases between the activated HRP and amino groups of the IgG. The quantitative molecular characterization data of the starting samples, intermediates, and final product were obtained by multi-detection SEC. Titration of the prepared conjugate was performed by the ELISA and its optimal working dilution was determined. This methodology proved to be a promising and powerful technology for the IgG-HRP conjugate process control and development, as well as for the quality control of the final product, as verified by the analysis of several commercially available reagents.

Micro-flow imaging multi-instrument evaluation for sub-visible particle detection

Sub-visible particles (SVPs) in pharmaceutical products are a critical quality attribute, and therefore should be monitored during development. Although light obscuration (LO) and microscopic particle count tests are the primary pharmacopeial methods used to quantify SVPs, flow imaging methods like Micro-Flow Imaging (MFI™) appear to overcome shortcomings of LO such as limited sensitivity concerning smaller translucent SVPs in the size range < 10 µm. Nowadays, MFI™ is routinely utilized during development of biologicals. Oftentimes multiple devices are distributed across several laboratories and departments. This poses challenges in data interpretation and consistency as well as in the use of multiple devices for one purpose. In this study, we systematically evaluated seven MFI™ instruments concerning their counting and size precision and accuracy, using an inter-comparable approach to mimic daily working routine. Therefore, we investigated three different types of particles (i) NIST certified counting standards, (ii) protein-coated particles, and (iii) stress-induced particles from a monoclonal antibody. We compared the results to alternative particle detection methods: LO and Backgrounded Membrane Imaging (BMI). Our results showed that the precision and accuracy of particle count and size, as well as the comparability of instruments, depended on the particle source and its material properties. The various MFI™ instruments investigated showed high precision (<15 %) and data generated on different instruments were of the same order of magnitude within pharmacopeial relevant size ranges for NIST certified counting standards. However, we found limitations in the upper and lower detection limits, contrary to the limits claimed by the manufacturer. In addition, proteinaceous and protein-containing particles showed statistically significant differences in particle counts, while the measured particle diameters of all sizes were quite consistent.

Effect of Processing Methods of Human Saliva on the Proteomic Profile and Protein-Mediated Biological Processes

The use of saliva as a protein source prior to microbiological and biological assays requires previous processing. However, the effect of these processing methods on the proteomic profile of saliva has not been tested. Stimulated human saliva was collected from eight healthy volunteers. Non-processed saliva was compared with 0.22 μm filtered, 0.45 μm filtered, and pasteurized saliva, by liquid chromatography-mass spectrometry. Data are available via ProteomeXchange with identifier PXD039248. The effect of processed saliva on microbial adhesion was tested using bacterial and fungus species and in biological cell behavior using HaCaT immortalized human keratinocytes. Two hundred and seventy-eight proteins were identified in non-processed saliva, of which 54 proteins (≈19%) were exclusive. Saliva processing reduced identified proteins to 222 (≈80%) for the 0.22 μm group, 219 (≈79%) for the 0.45 μm group, and 201 (≈72%) for the pasteurized saliva, compared to non-processed saliva. The proteomic profile showed similar molecular functions and biological processes. The different saliva processing methods did not alter microbial adhesion (ANOVA, p > 0.05). Interestingly, pasteurized saliva reduced keratinocyte cell viability. Saliva processing methods tested reduced the proteomic profile diversity of saliva but maintained similar molecular functions and biological processes, not interfering with microbial adhesion and cell viability, except for pasteurization, which reduced cell viability.

Drug Product Characterization of High Concentration Non-Aqueous Protein Powder Suspensions

High concentration protein formulations for subcutaneous injection represent a substantial number of development projects in the pharmaceutical industry. Such concentrated aqueous protein solutions face some specific challenges such as increased viscosity and aggregation propensity. Protein powder suspensions in non-aqueous vehicles could be an alternative providing lower viscosity than the respective aqueous solution. The choice of potential suspension vehicles is limited as traditional non-aqueous liquids, such as oils, show an inherent high viscosity. We studied suspensions prepared by dispersing spray-dried protein powder in different vehicles including sesame oil and medium chain triglycerides, as well as fluorinated and semifluorinated alkanes. We found, that semifluorinated alkanes enable formulations with high concentrations up to 280 mg/ml monoclonal antibody with a low viscosity of less than 10 mPa·s and low injection forces. The glide force of suspensions containing 210 mg/ml protein was not affected by the particle size of the spray-dried powders with medians ranging from 1 to 14 µm. In contrast, suspensions prepared with cryo-milled powder showed markedly higher viscosities and were not injectable at the same concentration. Protein powder suspensions were syringeable using a 25G needle. Vial filling using a peristaltic pump was possible and lead to a uniform filling. Sedimentation of the suspension was slow and does not lead to challenges upon vial filling during manufacturing or transfer of the suspension into syringes. Thus, we could show that dispersions of spray-dried protein powders in non-aqueous vehicles, such as semifluorinated alkanes, are a promising alternative to aqueous protein solutions at high concentrations.

Comparative Evaluation of the Performance of Sterile Filters for Bioburden Protection and Final Fill in Biopharmaceutical Processes

Sterile filtration processes are widely used in the production of biotherapeutics for microorganism removal and product sterility. Sterile filtration processes can be applied to buffer preparation and cell culture media preparation in biotherapeutics processes, and to final sterilization or final filling in downstream processes. Owing to their broad range of applications in bioprocessing, various 0.2/0.22 μm sterile filters with different polymer materials (i.e., hydrophilic PVDF and PES) and nominal pore sizes are commercially available. The objective of this study was to evaluate two different commercial sterile filters in terms of filtration performance in various sterile filtration processes of biopharmaceutical production. The results demonstrate the importance of choosing the appropriate filter considering the process type and target removal/transport product to ensure efficient sterile filtration in the production of biotherapeutics.

Modified Bundle of Capillaries Approximation of Sterilizing Filter Membranes and its use for Filter Characterization and Filtration Process Optimization

Sterilizing filtration is a common unit operation for the manufacture of parenteral drug products. However, filter performance can be impacted by properties of both the membrane material and the solution being filtered, requiring extensive multi-factor studies to optimize the filtration process for a given drug product. Here, we report the use of a modified bundle of capillaries approximation to predict filter performance. The model is directly applicable for both Newtonian and non-Newtonian solutions and does not require assumptions of steady state. Using a hydrophilic polyvinylidene difluoride (PVDF) filter as a test case, we show that the model fitting parameters align with expected values and both flux and shear are well predicted. Moreover, two case studies are presented to demonstrate the model's utility for filtration process optimization: 1) protein adsorption of an antibody formulation and 2) filter fouling of a 1% (w/v) carboxymethylcellulose (CMC) solution. In both cases, the model was able to accurately identify optimal filtration parameters to reduce the amount of adsorption or improve the filter capacity, respectively. This methodology can be easily extended to alternate filter types and provides an additional predictive tool to speed process development and minimize trial and error during filtration process design.

Stress Factors in Protein Drug Product Manufacturing and Their Impact on Product Quality

Injectable protein-based medicinal products (drug products, or DPs) must be produced by using sterile manufacturing processes to ensure product safety. In DP manufacturing the protein drug substance, in a suitable final formulation, is combined with the desired primary packaging (e.g., syringe, cartridge, or vial) that guarantees product integrity and enables transportation, storage, handling and clinical administration. The protein DP is exposed to several stress conditions during each of the unit operations in DP manufacturing, some of which can be detrimental to product quality. For example, particles, aggregates and chemically-modified proteins can form during manufacturing, and excessive amounts of these undesired variants might cause an impact on potency or immunogenicity. Therefore, DP manufacturing process development should include identification of critical quality attributes (CQAs) and comprehensive risk assessment of potential protein modifications in process steps, and the relevant steps must be characterized and controlled. In this commentary article we focus on the major unit operations in protein DP manufacturing, and critically evaluate each process step for stress factors involved and their potential effects on DP CQAs. Moreover, we discuss the current industry trends for risk mitigation, process control including analytical monitoring, and recommendations for formulation and process development studies, including scaled-down runs.

Translational Applications of Hydrogels

Advances in hydrogel technology have unlocked unique and valuable capabilities that are being applied to a diverse set of translational applications. Hydrogels perform functions relevant to a range of biomedical purposes-they can deliver drugs or cells, regenerate hard and soft tissues, adhere to wet tissues, prevent bleeding, provide contrast during imaging, protect tissues or organs during radiotherapy, and improve the biocompatibility of medical implants. These capabilities make hydrogels useful for many distinct and pressing diseases and medical conditions and even for less conventional areas such as environmental engineering. In this review, we cover the major capabilities of hydrogels, with a focus on the novel benefits of injectable hydrogels, and how they relate to translational applications in medicine and the environment. We pay close attention to how the development of contemporary hydrogels requires extensive interdisciplinary collaboration to accomplish highly specific and complex biological tasks that range from cancer immunotherapy to tissue engineering to vaccination. We complement our discussion of preclinical and clinical development of hydrogels with mechanical design considerations needed for scaling injectable hydrogel technologies for clinical application. We anticipate that readers will gain a more complete picture of the expansive possibilities for hydrogels to make practical and impactful differences across numerous fields and biomedical applications.

A Road Map to GMP Readiness for Protein Therapeutics - Drug Product Process Development for Clinical Supply

Biopharmaceuticals for human use present unique challenges during manufacturing, storage, shipment, and administration. Not all drug product process development aspects can and should be studied in detail before entering in first-in human studies (FIH) due to limited resources and the need for new drug candidates to enter phase 1 clinical studies quickly. Whilst activities for formulation development studies are well defined in literature, there is a lack of regulatory guidance for phase appropriate process development studies for clinical supplies. This review summarizes potential process development studies for liquid protein formulations and proposes a phase appropriate testing approach.

Stability of a high-concentration monoclonal antibody solution produced by liquid-liquid phase separation

Subcutaneous injection of a low volume (<2 mL) high concentration (>100 mg/mL) formulation is an attractive administration strategy for monoclonal antibodies (mAbs) and other biopharmaceutical proteins. Using concentrated solutions may also be beneficial at various stages of bioprocessing. However, concentrating proteins by conventional techniques, such as ultrafiltration, can be time consuming and challenging. Isolation of the dense fraction produced by macroscopic liquid–liquid phase separation (LLPS) has been suggested as a means to produce high-concentration solutions, but practicality of this method, and the stability of the resulting protein solution have not previously been demonstrated. In this proof-of-concept study, we demonstrate that LLPS can be used to concentrate a mAb solution to >170 mg/mL. We show that the structure of the mAb is not altered by LLPS, and unperturbed mAb is recoverable following dilution of the dense fraction, as judged by ¹H nuclear magnetic resonance spectroscopy. Finally, we show that the physical properties and stability of a model high concentration protein formulation obtained from the dense fraction can be improved, for example through the addition of the excipient arginine·glutamate. This results in a stable high-concentration protein formulation with reduced viscosity and no further macroscopic LLPS. Concentrating mAb solutions by LLPS represents a simple and effective technique to progress toward producing high-concentration protein formulations for bioprocessing or administration.

Abbreviations

Arginine·glutamate (Arg·Glu), Carr-Purcell-Meiboom-Gill (CPMG), critical temperature (T_C), high-performance size-exclusion chromatography (HPSEC), liquid–liquid phase separation (LLPS), monoclonal antibody (mAb), nuclear magnetic resonance (NMR), transverse relaxation rate (R₂)

HP-β-CD for the formulation of IgG and Ig-based biotherapeutics

The main challenge to develop HCF for IgG and Ig-based therapeutics is to achieve essential solubility, viscosity and stability of these molecules in order to maintain product quality and meet regulatory requirement during manufacturing, production, storage, shipment and administration processes. The commonly used and FDA approved excipients for IgG and Ig -based therapeutics may no longer fulfil the challenge of HCF development for these molecules to certain extent, especially for some complex Ig-based platforms. 2-Hydroxypropyl beta-cyclodextrin (HP-β-CD) is one of the promising excipients applied recently for HCF development of IgG and Ig-based therapeutics although it has been used for formulation of small synthesized chemical drugs for more than thirty years. This review describes essential aspects about application of HP-β-CD as excipient in pharmaceutical formulation, including physico-chemical properties of HP-β-CD, supply chain, regulatory, patent landscape, marketed drugs with HP-β-CD, analytics and analytical challenges, stability and control strategies, and safety concerns. It also provides an overview of different studies, and outcomes thereof, regarding formulation development for IgGs and Ig-based molecules in liquid and solid (lyophilized) dosage forms with HP-β-CD. The review specifically highlights the challenges for formulation manufacturing of IgG and Ig-based therapeutics with HP-β-CD and identifies areas for future work in pharmaceutical and formulation development.

Container Closure and Delivery Considerations for Intravitreal Drug Administration

Intravitreal (IVT) administration of therapeutics is the standard of care for treatment of back-of-eye disorders. Although a common procedure performed by retinal specialists, IVT administration is associated with unique challenges related to drug product, device and the procedure, which may result in adverse events. Container closure configuration plays a crucial role in maintaining product stability, safety, and efficacy for the intended shelf-life. Careful design of primary container configuration is also important to accurately deliver small volumes (10-100 μL). Over- or under-dosing may lead to undesired adverse events or lack of efficacy resulting in unpredictable and variable clinical responses. IVT drug products have been traditionally presented in glass vials. However, pre-filled syringes offer a more convenient administration option by reducing the number of steps required for dose preparation there by potentially reducing the time demand on the healthcare providers. In addition to primary container selection, product development studies should focus on, among other things, primary container component characterization, material compatibility with the formulation, formulation stability, fill volume determination, extractables/leachables, and terminal sterilization. Ancillary components such as disposable syringes and needles must be carefully selected, and a detailed administration procedure that includes dosing instructions is required to ensure successful administration of the product. Despite significant efforts in improving the drug product and administration procedures, ocular safety concerns such as endophthalmitis, increased intraocular pressure, and presence of silicone floaters have been reported. A systematic review of available literature on container closure and devices for IVT administration can help guide successful product development.

Understanding Loss of Soluble High Molecular Weight Species during Filtration of Low Concentration Therapeutic Monoclonal Antibodies

Sterile filtration is an integral step in the manufacturing process of biological therapeutics. Protein adsorption to the surface of the filter is an unfortunate, common occurrence that can result in manufacturing difficulties, such as filter fouling or product loss. Although many filters have surface modifications to minimize adsorption, under certain conditions binding can still occur. We observed the loss of high molecular weight species (HMWS) during sterile filtration of eight different therapeutic monoclonal antibodies formulated at low protein concentrations across a commonly used hydrophilic polyvinylidene fluoride or polyvinylidene difluoride (PVDF) filter membrane. The protein absorption was specific to HMWS, and each antibody exhibited different degrees of filter adsorption. Debye screening length parameters of the solution (e.g. ionic strength) were adjusted, and influenced the amount of HMWS lost during filtration. Additionally, HMWS of a representative antibody (mAb1) were observed to be more positively charged than other size variants by ion-exchange chromatography. From these results, it is concluded that this HMWS loss is due to electrostatic interactions between HMWS and the filter surface. This adsorption can be reduced by increasing the ionic strength of the buffer matrix, demonstrating the influence of the Debye screening length in the filtration of low concentration proteins.

Development challenges of high concentration monoclonal antibody formulations

High concentration monoclonal antibody drug products represent a special segment of biopharmaceuticals. In contrast to other monoclonal antibody products, high concentration monoclonal antibodies are injected subcutaneously helping increase patient compliance and reduce the number of hospital patient visits. It is important to note that a high protein concentration (≥50 mg/mL) poses a challenge from a product development perspective. Colloidal properties, physical and chemical protein stability should be considered during formulation, primary packaging and manufacturing process development as well as optimization of other dosage form-related parameters. The aim of such development work is to obtain a drug product capable of maintaining appropriate protein structure throughout its shelf-life and ensure proper and accurate dosage upon administration.

Science and art of protein formulation development

Protein pharmaceuticals have become a significant class of marketed drug products and are expected to grow steadily over the next decade. Development of a commercial protein product is, however, a rather complex process. A critical step in this process is formulation development, enabling the final product configuration. A number of challenges still exist in the formulation development process. This review is intended to discuss these challenges, to illustrate the basic formulation development processes, and to compare the options and strategies in practical formulation development.

Next Generation Biopharmaceuticals: Product Development

Therapeutic proteins show a rapid market growth. The relatively young biotech industry already represents 20 % of the total global pharma market. The biotech industry environment has traditionally been fast-pasted and intellectually stimulated. Nowadays the top ten best selling drugs are dominated by monoclonal antibodies (mABs).Despite mABs being the biggest medical breakthrough in the last 25 years, technical innovation does not stand still.The goal remains to preserve the benefits of a conventional mAB (serum half-life and specificity) whilst further improving efficacy and safety and to open new and better avenues for treating patients, e.g., improving the potency of molecules, target binding, tissue penetration, tailored pharmacokinetics, and reduced adverse effects or immunogenicity.The next generation of biopharmaceuticals can pose specific chemistry, manufacturing, and control (CMC) challenges. In contrast to conventional proteins, next-generation biopharmaceuticals often require lyophilization of the final drug product to ensure storage stability over shelf-life time. In addition, next-generation biopharmaceuticals require analytical methods that cover different ways of possible degradation patterns and pathways, and product development is a long way from being straight forward. The element of "prior knowledge" does not exist equally for most novel formats compared to antibodies, and thus the assessment of critical quality attributes (CQAs) and the definition of CQA assessment criteria and specifications is difficult, especially in early-stage development.

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.

Challenges for the pharmaceutical technical development of protein coformulations

Objectives

This review discusses challenges to stability, analytics and manufacturing of protein coformulations. Furthermore, general considerations to be taken into account for the pharmaceutical development of coformulated protein drug products are highlighted.

Key findings

Coformulation of two or more active substances in one single dosage form has recently seen increasing use offering several advantages, such as increased efficacy and/or the overall reduction of adverse event incidents in patients. Most marketed coformulated drug products are composed of small molecules. As proteins are not only comparatively large but also complex molecules, the maintenance of their physicochemical integrity within a formulation throughout pharmaceutical processing, storage, transport, handling and patient administration to ensure proper pharmacokinetics and pharmacodynamics in vivo already represents various challenges for single-entity products. Thus, nowadays, only sparse biologics-based coformulations can be found, as additional complexity during development is given for these products.

Summary

The complexity of the dosage form and the protein molecules results into additional challenges to formulation, manufacture, storage, transport, handling and patient administration, stability and analytics during the pharmaceutical development of protein coformulations. Various points have to be considered during different stages of development in order to obtain a safe and efficacious product.