In-Use Interfacial Stability of Monoclonal Antibody Formulations Diluted in Saline i.v. Bags

Development of an ELISA-based device to quantify antibody adsorption directly on medical plastic surfaces

Monoclonal antibodies (mAbs) encounter numerous interfaces during manufacturing, storage, and administration. While protein adsorption at the solid/liquid interface has been widely explored on model surfaces, a key challenge remains - the detection of very small amounts of adsorbed mAb directly on real medical surfaces. This study introduces a novel ELISA-based device, ELIBAG, a new tool for measuring mAb adsorption on medical bags. The efficacy of this device was highlighted by successfully confirming the adsorption of an IgG1 on two medical bag types: a polypropylene IV administration bag and a low-density polyethylene pharmaceutical manufacturing bag. We also investigated IgG1 adsorption on plastic model surfaces, revealing a similar range of mAb bulk concentration for surface saturation on both model and bag surfaces. This innovative device, characterized by its high-throughput and rapid approach, paves the way for extensive investigations into therapeutic proteins, such as mAbs, adsorption on a variety of medical or pharmaceutical surfaces, diverse adsorption conditions, and the influence of excipients employed in mAb formulation, which could enhance the knowledge of mAb interactions with plastic surfaces throughout their lifecycle.

Feasibility of Laboratory Equipment-Based Simulation Methods to Assess the Impact of Vehicle Transportation on Product Quality of mAb Dosing Solutions

Therapeutic monoclonal antibody (mAb) products for intravenous (IV) administration generally require aseptic compounding with a commercially available diluent. When the administration site is located away from the preparation site, the prepared dosing solution may need to be transported in a vehicle. The impact of vehicle transportation on the product quality of mAbs needs to be evaluated to define safe handling and transportation conditions for dosing solutions. The design and execution of actual vehicle transportation studies require considerable resources and time. In this study, we systematically developed three different laboratory equipment-based methods that simulate vehicle transportation stresses: orbital shaker (OS), reciprocating shaker (RS), and vibration test system (VTS)-based simulation methods. We assessed their feasibility by comparing the impact on product quality caused by each simulated method with that caused by actual vehicle transportation. Without residual polysorbate 80 (PS80) in the mAb dosing solution, transportation via a cargo van led to a considerable increase in the subvisible particle counts and did not meet the compendial specifications for the light obscuration method. However, the presence of as low as 0.0004%w/v (4 ppm) PS80 in the dosing solution stabilized the mAb against vehicle transportation stresses and met the compendial specifications. Vehicle transportation of an IV bag with headspace resulted in negligible micro air bubbles and foaming in both PS80-free and PS80-containing mAb dosing solutions. These phenomena were found to be comparable to the VTS-based simulated method. However, the OS- and RS-based simulated methods formed significantly more micro air bubbles and foaming in an IV bag with headspace than either actual vehicle transportation or the VTS-based simulated method. Despite the higher interfacial stress (micro air bubbles and foaming) in the dosing solution created by the OS- and RS-based simulated methods, 0.0004%w/v (4 ppm) PS80 in the dosing solution was found to be sufficient to stabilize the mAb. The study shows that under appropriate simulated conditions, the OS-, RS-, and VTS-based simulated methods can be used as practical and meaningful models to assess the impact and risk of vehicle transportation on the quality of mAb dosing solutions.

Impact of stirring material on formation of submicron and subvisible aggregates in mAbs by quantitative laser diffraction, dynamic light scattering and background membrane imaging

Aggregation of monoclonal antibodies (mAbs) is the driving force for their undesirable immunogenic effects. There are multiple factors responsible for aggregation in therapeutic proteins. One significant cause is the process-related shear and interfacial stress generated due to impellers and stirrers. This investigation focuses on understanding the possible aggregation arising upon stirring mAb formulations using stirrers made of different materials. We used quantitative laser diffraction (qLD) to monitor and quantify the stirring induced formation of submicron and subvisible aggregates in the size range from 100 nm to 10 µm. We analysed various aspects of aggregate generation, such as onset of aggregation, particle size distribution, and concentration of aggregates generated using stirrers of different materials. We observed that mixing with stainless steel stirrers resulted in a quicker onset of aggregation and led to significantly higher concentrations of aggregates. Analysis of the stirred samples using dynamic light scattering (DLS) and background imaging technique (BMI) were conducted to complement the qLD analysis. All the three techniques resulted in a similar trend, showing presence of larger and higher quantities of aggregates in steel stirred samples, as compared to those stirred using PEEK and glass. Additionally, we performed SEC-HPLC to quantify the soluble fraction of monomer and recorded that the least amount was present in the steel stirred samples. This work highlights the need for optimizing the materials used for fabricating the stirrers/impellers.

Stress-mediated polysorbate 20 degradation and its potential impact on therapeutic proteins

PURPOSE

Polysorbates are the most commonly used surfactants in formulations to stabilize therapeutic proteins against interfacial stresses. Polysorbates can undergo oxidative or enzyme-mediated hydrolytic degradation to produce free fatty acids (FFAs) and subvisible particles in formulations. To determine which product related variables contribute to PS20 degradation, we investigated the effects of storage temperature, formulation, pH, presence of hydrolytic enzymes, and specific fatty acid composition on different grades of PS20 in relation to their PS20 degradation profile and consequently the quality of protein drug products.

METHODS

Bevacizumab and T-DM1 were reformulated in the freshly prepared therapeutic protein formulations containing either compendial PS20 or non-compendial PS20 with high % lauric acid and spiked with exogenous esterase or lipase. The release of FFAs and formation of particles were monitored at 4°C and 37°C. Protein quality was assessed for secondary structures, purity, and biological activity.

RESULTS

Hydrolytic release of FFAs and formation of subvisible particles were found to be dependent on grades of PS20, types of enzymes used, incubation temperature, and pH. Esterase- or lipase-mediated degradation of PS20 and formation of subvisible particles in drug formulation showed no significant impact on the biological activity and stability of therapeutic proteins against degradation or aggregation.

CONCLUSIONS

Our study suggests that degradation of PS20 and formation of FFA particles depend on the fatty acid composition of PS20, types of hydrolytic enzymes, pH, and temperature. The presence of FFA subvisible particles showed no significant impact on the purity and biological activity of the therapeutic proteins under the tested conditions.

Using Passive Microrheology to Measure the Evolution of the Rheological Properties of NIST mAb Formulations during Adsorption to the Air-Water Interface

The development of novel protein-based therapeutics, such as monoclonal antibodies (mAbs), is often limited due to challenges associated with maintaining the stability of these formulations during manufacturing, storage, and clinical administration. An undesirable consequence of the instability of protein therapeutics is the formation of protein particles. MAbs can adsorb to interfaces and have the potential to undergo partial unfolding as well as to form viscoelastic gels. Further, the viscoelastic properties may be correlated with their aggregation potential. In this work, a passive microrheology technique was used to correlate the evolution of surface adsorption with the evolution of surface rheology of the National Institute of Standards and Technology (NIST) mAb reference material (NIST mAb) and interface-induced subvisible protein particle formation. The evolution of the surface adsorption and interfacial shear rheological properties of the NIST mAb was recorded in four formulation conditions: two different buffers (histidine vs phosphate-buffered saline) and two different pHs (6.0 and 7.6). Our results together demonstrate the existence of multiple stages for both surface adsorption and surface rheology, characterized by an induction period that appears to be purely viscous, followed by a sharp increase in protein molecules at the interface when the film rheology is viscoelastic and ultimately a slowdown in the surface adsorption that corresponds to the formation of solid-like or glassy films at the interface. When the transitions between the different stages occurred, they were dependent on the buffer/pH of the formulations. The onset of these transitions can also be correlated to the number of protein particles formed at the interface. Finally, the addition of polysorbate 80, an FDA-approved surfactant used to mitigate protein particle formation, led to the interface being surfactant-dominated, and the resulting interface remained purely viscous.

Development and Qualification of Analytical Methods to Support Low Concentration Drug Product in-use Studies

The emergence of highly potent therapeutics with low expected clinical doses creates a challenge for analytical characterization of simulated drug product in-use samples. The low expected protein concentration (often µg/mL) and highly charged and sub-optimal sample matrices like 0.9% saline or 5% dextrose make ensuring dose solution stability and characterizing product quality changes difficult. Health authority expectations require analysis of low concentration in-use samples to be completed with suitable assays to ensure little to no changes are occurring during drug product dose preparation and administration, thus ensuring patient safety. However, characterization of these samples for protein concentration, size variants, charge variants and potency often necessitates additional analytical method development to improve sensitivity and compatibility with in-use samples. Here we report the development and qualification of reliable in-use methods to characterize simulated in-use samples to assist during drug product development.

Taurine, a Naturally Occurring Amino Acid, as a Physical Stability Enhancer of Different Monoclonal Antibodies

Degradation of therapeutic monoclonal antibodies (mAbs) is a major concern as it affects efficacy, shelf-life, and safety of the product. Taurine, a naturally occurring amino acid, is investigated in this study as a potential mAb stabilizer with an extensive analytical characterization to monitor product degradation. Forced degradation of trastuzumab biosimilar (mAb1)-containing samples by thermal stress for 30 min resulted in high-molecular-weight species by more than 65% in sample without taurine compared to the sample with taurine. Samples containing mAb1 without taurine also resulted in higher Z-average diameter, altered protein structure, higher hydrophobicity, and lower melting temperature compared to samples with taurine. The stabilizing effect of taurine was retained at different mAb and taurine concentrations, time, temperatures, and buffers, and at the presence of polysorbate 80 (PS80). Even the lowest taurine concentration (10 mM) considered in this study, which is in the range of taurine levels in amino acid injections, resulted in enhanced mAb stability. Taurine-containing samples resulted in 90% less hemolysis than samples containing PS80. Additionally, mAb in the presence of taurine showed enhanced stability upon subjecting to stress with light of 365 nm wavelength, combination of light and H2O2, and combination of Fe2+ and H2O2, as samples containing mAb without taurine resulted in increased degradation products by more than 50% compared to samples with taurine upon subjecting to these stresses for 60 min. In conclusion, the presence of taurine enhanced physical stability of mAb by preventing aggregate formation, and the industry can consider it as a new mAb stabilizer.

Enzymatic degradation pattern of polysorbate 20 impacts interfacial properties of monoclonal antibody formulations

Polysorbate 20 (PS20) is widely used to maintain protein stability in biopharmaceutical formulations. However, PS20 is susceptible to hydrolytic degradation catalyzed by trace amounts of residual host cell proteins present in monoclonal antibody (mAb) formulations. The resulting loss of intact surfactant and the presence of PS20 degradation products, such as free fatty acids (FFAs), may impair protein stability. In this study, two hydrolytically-active immobilized lipases, which primarily targeted either monoester or higher-order ester species in PS20, were used to generate partially-degraded PS20. The impact of PS20 degradation pattern on critical micelle concentration (CMC), surface tension, interfacial rheology parameters and agitation protection was assessed. CMC was slightly increased upon monoester degradation, but significantly increased upon higher-order ester degradation. The PS20 degradation pattern also significantly impacted the dynamic surface tension of a mAb formulation, whereas changes in the equilibrium surface tension were mainly caused by the adsorption of FFAs onto the air-water interface. In an agitation protection study, monoester degradation resulted in the formation of soluble mAb aggregates and proteinaceous particles, suggesting that preferential degradation of PS20 monoester species can significantly impair mAb stability. Additional mAbs should be tested in the future to assess the impact of the protein format.

Quartz Crystal Microbalance as a Predictive Tool for Drug-Material of Construction Interactions in Intravenous Protein Drug Administration

As a growing number of protein drug products are developed, formulation characterization is becoming important. An IgG drug product is tested at concentrations from 0.0001-0.1 mg/mL for adsorption behavior to polymer surfaces polyvinyl chloride (PVC) and polypropylene (PP) upon dilution in normal saline (NS) using quartz crystal microbalance with dissipation (QCM-D). The studies mimicked IgG antibody interaction during IV administration with polymeric surfaces within syringes, lines, and bags. Drug product was characterized with excipients, with focus on surfactant. Drug solutions were run over polymer-coated sensors to measure the adsorption behavior of the formulation with emphasis on the behavior of each of the formulation's components. Over 60 sensorgram data sets were correlated with assayed protein solution concentrations in mock NS-diluted infusions of drug product in the equivalent concentrations to QCM experiments to build a preliminary predictive model for determining fraction of drug and surfactant adsorbed and lost at the hydrophobic surface during administration. These results create a method for reliably and predictively estimating drug product adsorption behavior and protein drug dose loss on polymers at different protein drug concentrations.

Evaluation of the In-Use Stability of Monoclonal Antibody IV Admixtures Prepared from Drug Products Containing Polysorbate 20 Degraded by Host-Cell Lipases

Host-cell lipases can be present in monoclonal antibody drug products and can degrade polysorbates present in the formulations as stabilizers. We hypothesized that the in-use stability of the IV admixture prepared from such a drug product might be impacted by decreasing levels of polysorbate 20. Host-cell lipase activity has, in fact, been observed during development of one of our therapeutic monoclonal antibody drug products. Throughout the course of the product shelf life, polysorbate 20 levels decreased but no other quality attributes of the drug product were impacted. An experimental approach was developed to simulate how the prepared IV admixture in-use stability is affected as polysorbate 20 concentration in the drug product decreased over the shelf life, and from that a minimum level of polysorbate 20 required in the drug product was determined to estimate the in-use stability of the IV admixture as the polysorbate 20 in the drug product degrades. The results indicate that although the observed degradation of polysorbate 20 does not affect quality attributes of this drug product, in-use stability of the IV admixture as a function of polysorbate degradation can be impacted and should be assessed to ensure sufficient quality.

Interfacial Pressure and Viscoelasticity of Antibodies and Their Correlation to Long-Term Stability in Formulation

Monoclonal antibodies (mAbs) form viscoelastic gel-like layers at the air-water interface due to their amphiphilic nature, and this same protein characteristic can lead to undesired aggregation of proteins in therapeutic formulations. We hypothesize that the interfacial viscoelasticity and surface pressure of mAbs at the air-water interface will correlate with their long-term stability. To test this hypothesis, the interfacial viscoelastic rheology and surface pressure of five different antibodies with varying visible particle counts from a three-year stability study were measured. We find that both the surface pressures and interfacial elastic moduli correlate well with the long-time mAb solution stability within a class of mAbs with the interfacial elastic moduli being particularly sensitive to discriminate between stable and unstable mAbs across a range of formulations. Furthermore, X-ray reflectivity was used to gain insight into the interfacial structure of mAbs at the air-water interface, providing a possible molecular mechanism to explain the relationship between interfacial elastic moduli and the long-term stability.

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.

Automated High-Throughput Matrix Assisted Laser Desorption Ionization Mass Spectrometry Methodology for Formulation Assessment of Polyethylene-Glycol-Conjugated Cytokine Proteins

Biological therapeutics are major contributors to the pharmaceutical pipeline and continue to grow in sales and scope. Additionally, the field's understanding of cancer biology has advanced such that biopharmaceuticals can harness the power of the immune system for oncology treatments. Several of these novel therapeutics are engineered versions of naturally occurring proteins designed to improve therapeutic properties including potency, target engagement and half-life extension. Cytokines, such as interferons and interleukins, are a broad class of signaling proteins which modulate the body's immune response; engineered cytokines have entered the clinic as promising new immuno-oncology therapies. While these therapies hold great promise, their additional structural complexity introduces analytical challenges, and traditional analytical platforms may be ill-suited to effectively assess product development risks. Further, the pharmaceutical industry relies on streamlining approaches for high-throughput experimentation to achieve speed and efficiency for the discovery and development of new modalities. These demands necessitate the use of state-of-the-art techniques to rapidly characterize these new modalities and guide process development and optimization. Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) is a rapid, sensitive and automatable technique amenable for high-throughput analysis of proteins. In this work, we have developed an automated MALDI-MS platform to prepare, acquire and analyze molecular degradation in engineered PEGylated cytokines formulation samples. This orthogonal technique integrated seamlessly with current developability risk assessment workflows, ultimately enabling selection of a final formulation strategy for clinical development.

Real-Time Assessment of the Size Changes of Individual Sub-Visible Protein Particles under Buffer Variations: A Microfluidic Study

Protein particles in biological drugs can significantly impact drug efficacy and carry the risk of adverse effects. Despite advancements, the understanding and control of particle formation in biopharmaceutical manufacturing remain incomplete. Therefore, further investigation into protein particles is warranted, especially considering that novel formats of biological drugs may be more susceptible to aggregation and particle formation than conventional monoclonal antibodies. In this study, we introduce a microfluidic approach for the real-time analysis of individual sub-visible protein particles during buffer exchange. We find that the modulation of intermolecular forces, achieved by changing the buffer pH or urea concentration, leads to the reversible swelling and shrinkage of particles by up to 50%, which is a consequence of altered intermolecular distances. Additionally, we identify a discrepancy in the biophysical behavior of protein particles compared to monomeric protein. This finding highlights the limited predictive power of commonly applied biophysical characterization methods for particle formation in early formulation development. Moreover, the observed particle swelling may be associated with manufacturing deviations, such as filter clogging. These results highlight the importance of studying individual particles to gain a comprehensive insight into particle behavior and the impact of formulation variations in the biopharmaceutical industry.

Combined Presence of Ferrous Ions and Hydrogen Peroxide in Normal Saline and In Vitro Models Induces Enhanced Aggregation of Therapeutic IgG due to Hydroxyl Radicals

Therapeutic monoclonal antibodies (mAb) are known to form aggregates and fragments upon exposure to hydrogen peroxide (H₂O₂) and ferrous ions (Fe²⁺). H₂O₂ and Fe²⁺ react to form hydroxyl radicals that are detrimental to protein structures. In this study, aggregation of mAb in the combined presence of Fe²⁺ and H₂O₂ was investigated in saline and physiologically relevant in vitro models. In the first case study, forced degradation of mAb in saline (a fluid used for administration of mAb) was carried out at 55 °C in the combined presence of 0.2 mM Fe²⁺ and 0.1% H₂O₂. The control and stressed samples were analyzed using an array of techniques including visual observation, size-exclusion chromatography (SEC), dynamic light scattering (DLS), microscopy, UV-vis, fluorescence, Fourier transform infrared spectroscopy, and cell-based toxicity assays. At the end of 1 h, samples having the combined presence of both Fe²⁺ and H₂O₂ exhibited more than 20% HMW (high molecular weight species), whereas samples having only Fe²⁺, H₂O₂, or neither resulted in less than 3% HMW. Aggregate-rich samples also exhibited altered protein structures and hydrophobicity. Aggregation increased upon increasing the time, temperature, and concentration of Fe²⁺ and H₂O₂. Samples having both Fe²⁺ and H₂O₂ also showed higher cytotoxicity in red blood cells. Samples of mAb with chlorides of copper and cobalt with H₂O₂ also resulted in multifold degradation. The first case study showed enhanced aggregation of mAb in the combined presence of Fe²⁺ and H₂O₂ in saline. In the second case study, aggregation of mAb was investigated in artificially prepared extracellular saline and in vitro models such as macromolecule free fraction of serum and serum. In the presence of both Fe²⁺ and H₂O₂, %HMW was higher in extracellular saline compared to macromolecule free fraction of serum. Further, in vitro models having the combined presence of Fe²⁺ and H₂O₂ resulted in enhanced aggregation of mAb compared to models that had neither.

Steps toward nebulization in-use studies to understand the stability of new biological entities

The need for novel biological drugs against respiratory diseases has been highlighted during the Coronavirus (COVID-19) pandemic. The use of inhalation presents challenges to drug product stability, which is especially true for delivery using nebulizers (jet versus mesh technologies). The late-stage process of drug development in the pharmaceutical industry requires the investigation of in-use stability. In-use studies generate data that are guided by the requirements of regulatory authorities for inclusion in the clinical trial application dossier. In this review, I introduce the initial aspects of in-use stability studies during the development of an aerosol formulation to deliver biologics with a nebulizer. Lessons learned from this experience can guide future development and planning for formulation, analytics, material compatibility, nebulization process, and clinical trial preparations.

Stable High-Concentration Monoclonal Antibody Formulations Enabled by an Amphiphilic Copolymer Excipient

Monoclonal antibodies are a staple in modern pharmacotherapy. Unfortunately, these biopharmaceuticals are limited by their tendency to aggregate in formulation, resulting in poor stability and often requiring low concentration drug formulations. Moreover, existing excipients designed to stabilize these formulations are often limited by their toxicity and tendency to form particles such as micelles. Here, we demonstrate the ability of a simple "drop-in", amphiphilic copolymer excipient to enhance the stability of high concentration formulations of clinically-relevant monoclonal antibodies without altering their pharmacokinetics or injectability. Through interfacial rheology and surface tension measurements, we demonstrate that the copolymer excipient competitively adsorbs to formulation interfaces. Further, through determination of monomeric composition and retained bioactivity through stressed aging, we show that this excipient confers a significant stability benefit to high concentration antibody formulations. Finally, we demonstrate that the excipient behaves as an inactive ingredient, having no significant impact on the pharmacokinetic profile of a clinically relevant antibody in mice. This amphiphilic copolymer excipient demonstrates promise as a simple formulation additive to create stable, high concentration antibody formulations, thereby enabling improved treatment options such as a route-of-administration switch from low concentration intravenous (IV) to high concentration subcutaneous (SC) delivery while reducing dependence on the cold chain.

Blueprint for antibody biologics developability

Large-molecule antibody biologics have revolutionized medicine owing to their superior target specificity, pharmacokinetic and pharmacodynamic properties, safety and toxicity profiles, and amenability to versatile engineering. In this review, we focus on preclinical antibody developability, including its definition, scope, and key activities from hit to lead optimization and selection. This includes generation, computational and in silico approaches, molecular engineering, production, analytical and biophysical characterization, stability and forced degradation studies, and process and formulation assessments. More recently, it is apparent these activities not only affect lead selection and manufacturability, but ultimately correlate with clinical progression and success. Emerging developability workflows and strategies are explored as part of a blueprint for developability success that includes an overview of the four major molecular properties that affect all developability outcomes: 1) conformational, 2) chemical, 3) colloidal, and 4) other interactions. We also examine risk assessment and mitigation strategies that increase the likelihood of success for moving the right candidate into the clinic.

End-to-End Approach to Surfactant Selection, Risk Mitigation, and Control Strategies for Protein-Based Therapeutics

A survey performed by the AAPS Drug Product Handling community revealed a general, mostly consensus, approach to the strategy for the selection of surfactant type and level for biopharmaceutical products. Discussing and building on the survey results, this article describes the common approach for surfactant selection and control strategy for protein-based therapeutics and focuses on key studies, common issues, mitigations, and rationale. Where relevant, each section is prefaced by survey responses from the 22 anonymized respondents. The article format consists of an overview of surfactant stabilization, followed by a strategy for the selection of surfactant level, and then discussions regarding risk identification, mitigation, and control strategy. Since surfactants that are commonly used in biologic formulations are known to undergo various forms of degradation, an effective control strategy for the chosen surfactant focuses on understanding and controlling the design space of the surfactant material attributes to ensure that the desired material quality is used consistently in DS/DP manufacturing. The material attributes of a surfactant added in the final DP formulation can influence DP performance (e.g., protein stability). Mitigation strategies are described that encompass risks from host cell proteins (HCP), DS/DP manufacturing processes, long-term storage, as well as during in-use conditions.

A Mechanistic Understanding of Monoclonal Antibody Interfacial Protection by Hydrolytically Degraded Polysorbate 20 and 80 under IV Bag Conditions

PURPOSE

Polysorbates (PS) contain polyoxyethylene (POE) sorbitan/isosorbide fatty acid esters that can partially hydrolyze over time in liquid drug products to generate degradants and a remaining intact PS fraction with a modified ester distribution. The degradants are composed of free fatty acids (FFAs) --primarily lauric acid for PS20 and oleic acid for PS80-- and POE head groups. We previously demonstrated that under IV bag agitation conditions, mAb1 (a surface-active IgG4) aggregation increased with increasing amounts of degradants for PS20 but not for PS80. The purpose of this work is to understand the mechanism behind this observation.

METHODS

The surface tension of the remaining intact PS fraction without degradants was modeled and compared with that of enzymatically degraded PS solutions. Next, mAb1 aggregation in saline was measured in the presence of laurate and oleate salts during static storage. Lastly, colloidal and conformational stability of mAb1 in the presence of these salts was investigated through differential scanning fluorimetry and dynamic light scattering under IV bag solution conditions.

RESULTS

The surface tension was primarily influenced by FFAs rather than the modified ester distribution of the remaining intact PS. MAb1 bulk aggregation increased in the presence of laurate but not oleate salts. Both salt types increased the melting temperature of mAb1 indicating FFA-mAb1 interactions. However, only laurate salt increased mAb1 self-association potentially explaining the higher aggregation propensity in its presence.

CONCLUSION

Our results help explain the observed differences between hydrolytically degraded PS20 and PS80 in affecting mAb1 aggregation under IV bag agitation conditions.

Evaluating a Modified High Purity Polysorbate 20 Designed to Reduce the Risk of Free Fatty Acid Particle Formation

PURPOSE

To evaluate a modified high purity polysorbate 20 (RO HP PS20)-with lower levels of stearate, palmitate and myristate esters than the non-modified HP PS20-as a surfactant in biopharmaceutical drug products (DP). RO HP PS20 was designed to provide functional equivalence as a surfactant while delaying the onset of free fatty acid (FFA) particle formation upon hydrolytic degradation relative to HP PS20.

METHODS

Analytical characterization of RO HP PS20 raw material included fatty acid ester (FAE) distribution, higher order ester (HOE) fraction, FFA levels and trace metals. Functional assessments included 1) vial and intravenous bag agitation; 2) oxidation via a placebo and methionine surrogate study; and 3) hydrolytic PS20 degradation studies to evaluate FFA particle formation with and without metal nucleation.

RESULTS

Interfacial protection and oxidation propensity were comparable between the two polysorbates. Upon hydrolytic degradation, FFA particle onset was delayed in RO HP PS20. The delay was more pronounced when HOEs of PS20 were preferentially degraded. Furthermore, the hydrolytic degradants of RO HP PS20 formed fewer particles in the presence of spiked aluminum.

CONCLUSION

This work highlights the criticality of having tighter control on long chain FAE levels of PS20 to reduce the occurrence of FFA particle formation upon hydrolytic degradation and lower the variability in its onset. By simultaneously meeting compendial PS20 specifications while narrowing the allowable range for each FAE and shifting its composition towards the shorter carbon chain species, RO HP PS20 provides a promising alternative to HP PS20 for biopharmaceutical DPs.

Off-label use of plastic syringes with silicone oil for intravenous infusion bags of antibodies

The formation of particulates in post-manufacture biopharmaceuticals continues to be a major concern in medical treatment. This study was designed to evaluate the content of micro-sized particles using flow imaging of antibodies in intravenous infusion bags. Intravenous immunoglobulin (IVIG) and Avastin® were selected as model drugs and plastic syringes with and without silicone oil (SO) were used to transfer the drugs into the bags (0.9% saline or 5% dextrose). Antibodies exposed to SO had significantly increased levels of microparticles in both diluents, suggesting SO accelerates particle formation, especially at a higher antibody concentration. Even before the drop stress, their count exceeded the USP guideline. Dropping the bags in the presence of SO produced larger microparticles. Meanwhile, air bubbles were retained longer in saline suggesting more protein film formation on its air-water interface. Overall, both drugs were conformationally stable and produced less particles in dextrose than in saline.

Stability study over time of clinical solutions of ziv-aflibercept prepared in infusion bags using a proper combination of physicochemical and functional strategies

A range of biopharmaceutical products are used to target Vascular Endothelial Growth Factor (VEGF), including Eylea® (aflibercept, AFL) and Zaltrap® (ziv-aflibercept, ziv-AFL). The first is indicated for ophthalmological diseases such as neovascular (wet) age-related macular degeneration, while the second is used in the treatment of metastatic colorectal cancer. The stability of AFL in prefilled syringes has been widely studied; however, no research has yet been done on the stability of ziv-AFL in polyolefin infusion bags. Therefore, the purpose of the present research is to evaluate the stability of ziv-AFL (Zaltrap®) clinical solutions prepared under aseptic conditions in polyolefin infusion bags at two different concentrations, i.e. 4.0 and 0.6 mg/mL, and stored refrigerated in darkness at 2-8 °C for 14 days. With that aim, the ziv-AFL clinical solutions were assessed by analysing changes in its physicochemical and functional properties. The distribution of the particulates was studied over a range of 0.001-10 μm by Dynamic Light Scattering (DLS); oligomers were analysed by Size-Exclusion High-Performance Chromatography with Diode Array Detection (SE/HLPC-DAD); the secondary structure of the protein was studied by far UV Circular Dichroism (CD) and the tertiary structure by Intrinsic Tryptophan Fluorescence (IT-F) and Intrinsic Protein Fluorescence (IP-F); charge variants were assessed by Strong Cation Exchange Ultra-High-Performance Chromatography with UV detection (SCX/UHPLC-UV); functionality was evaluated by ELISA by measuring the biological activity as manifested in the extension of the immunological reaction of the ziv-AFL with its antigen (VEGF). Neither aggregation nor oligomerization were detected by the techniques mentioned above. Secondary and tertiary structures remained unchanged over the 14-day period, as did charge variants. The functionality observed initially was maintained along time. Therefore, it could be proposed that the ziv-AFL clinical solutions studied showed great physicochemical and functional stability over a period of two weeks, regardless of the concentration, i.e. 4 or 0.6 mg/mL.

A Comprehensive Assessment of All-Oleate Polysorbate 80: Free Fatty Acid Particle Formation, Interfacial Protection and Oxidative Degradation

PURPOSE

Enzymatic polysorbate (PS) degradation and resulting free fatty acid (FFA) particles are detrimental to biopharmaceutical drug product (DP) stability. Different types and grades of polysorbate have varying propensity to form FFA particles. This work evaluates the homogenous all-oleate (AO) PS80 alongside heterogeneous PS20 and PS80 grades in terms its propensity to form FFA particles and other important attributes like interfacial protection and oxidation susceptibility.

METHODS

FFA particle formation rates were compared by degrading PS using non-immobilized hydrolases and fast degrading DP formulations. Interfacial protection of monoclonal antibodies (mAbs) was assessed by agitation studies in saline using non-degraded and degraded PS. Several antioxidants were assessed for their ability to mitigate AO PS80 oxidation and subsequent mAb oxidation by a 40°C placebo stability study and a 2, 2'-Azobis (2-amidinopropane) dihydrochloride stress model, respectively.

RESULTS

Visible and subvisible particles were significantly delayed in AO PS80 formulations compared with heterogeneous PS20 and PS80 formulations. Non-degraded AO PS80 was less protective of mAbs against the air-water interface compared with heterogeneous PS20. Interfacial protection by AO PS80 improved upon degradation owing to high surface activity of FFAs. Diethylenetriaminepentaacetic acid (DTPA) completely mitigated AO PS80 oxidation unlike L-methionine and N-Acetyl-DL-Tryptophan. However, DTPA did not mitigate radical mediated mAb oxidation.

CONCLUSION

AO PS80 is a promising alternative to reduce FFA particle formation compared with other PS types and grades. However, limitations observed here---such as lower protection against interfacial stresses and higher propensity for oxidation---need to be considered in assessing the risk/benefit ratio in using AO PS80.

Adsorption and Aggregation of Monoclonal Antibodies at Silicone Oil-Water Interfaces

Monoclonal antibody (mAb) therapies are rapidly growing for the treatment of various diseases like cancer and autoimmune disorders. Many mAb drug products are sold as prefilled syringes and vials with liquid formulations. Typically, the walls of prefilled syringes are coated with silicone oil to lubricate the surfaces during use. MAbs are surface-active and adsorb to these silicone oil-solution interfaces, which is a potential source of aggregation. We studied formulations containing two different antibodies, mAb1 and mAb2, where mAb1 aggregated more when agitated in the presence of an oil-water interface. This directly correlated with differences in surface activity of the mAbs, studied with interfacial tension, surface mass adsorption, and interfacial rheology. The difference in interfacial properties between the mAbs was further reinforced in the coalescence behavior of oil droplets laden with mAbs. We also looked at the efficacy of surfactants, typically added to stabilize mAb formulations, in lowering adsorption and aggregation of mAbs at oil-water interfaces. We showed the differences between poloxamer-188 and polysorbate-20 in competing with mAbs for adsorption to interfaces and in lowering particulate and overall aggregation. Our results establish a direct correspondence between the adsorption of mAbs at oil-water interfaces and aggregation and the effect of surfactants in lowering aggregation by competitively adsorbing to these interfaces.