Impact of the Design of Different Infusion Containers on the Dosing Accuracy of a Therapeutic Drug Product

Residual volumes of infusion solutions vary greatly due to container and dimensional variances. Manufacturers use overfill to compensate, but the exact amounts vary significantly. This variability in overfill - when carrier solutions are used to dilute other parenteral preparations - may lead to variable concentrations and dosing, hence, potential risk for patients. We analyzed the overfill and residual volume of 22 pre-filled infusion containers and evaluated the impact on the (simulated) dosing accuracy of a therapeutic drug product for different handling scenarios. In addition, compendial properties of the diluents (i.e. sub-visible particles, pH, color and opalescence) were assessed. The overfill and residual volume between different containers for the same diluent varied. As container size increased, the relative volume of overfill decreased while the residual volume remained constant. The design and material of the containers (e.g. port systems) defined the residual volume. Different handling scenarios led to differences in dosing accuracy. As a result, no universal approach applicable for all containers can be defined. To ensure the right dose, it is recommended to pre-select the preferred diluent, evaluate fill volumes of carrier solutions, and assess in-use compatibility of the product solution with its diluent in terms of concentration and volume.

A Survey on Handling and Administration of Therapeutic Protein Products in German and Swiss Hospitals

Protein products in hospitals often have to be compounded before administration to the patient. This may comprise reconstitution of lyophilizates, dilution, storage, and transport. However, the operations for compounding and administration in the hospital may lead to changes in product quality and possibly even impact patient safety. We surveyed healthcare practitioners from three clinical units using a questionnaire and open dialogue to document common procedures and their justification and to document differences in handling procedures. The survey covered dose compounding, transportation, storage and administration. One key observation was that drug vial optimization procedures were used for some products, e.g., use of one single-use vial for several patients. This included the use of spikes and needles or closed system transfer devices (CSTDs). Filters or light protection aids were used only when specified by the manufacturer. A further observation was a different handling of the overfill in pre-filled infusion containers, possibly impacting total dose. Lastly, we documented the complexity of infusion administration setups for administration of multiple drugs. In this case, flushing procedures or the placement and use of filters in the setup vary. Our study has revealed important differences in handling and administration practice. We propose that drug developers and hospitals should collaborate to establish unified handling procedures.

The Development of a Novel Aflibercept Formulation for Ocular Delivery

Aflibercept is a recombinant fusion protein that is commercially available for several ocular diseases impacting millions of people worldwide. Here, we use a case study approach to examine alternative liquid formulations for aflibercept for ocular delivery, utilizing different stabilizers, buffering agents, and surfactants with the goal of improving the thermostability to allow for limited storage outside the cold chain. The formulations were developed by studying the effects of pH changes, substituting amino acids for sucrose and salt, and using polysorbate 80 or poloxamer 188 instead of polysorbate 20. A formulation containing acetate, proline, and poloxamer 188 had lower rates of aggregate formation at 4, 30, and 40°C when compared to the marketed commercial formulation containing phosphate, sucrose, sodium chloride, and polysorbate 20. Further studies examining subvisible particles after exposure to a transport stress and long-term stability at 4°C, post-translational modifications by multi-attribute method, purity by reduced and non-reduced capillary electrophoresis, and potency by cell proliferation also demonstrated a comparable or improved stability for the enhanced formulation of acetate, proline, and poloxamer 188. This enhanced stability could enable limited storage outside of the cold chain, allowing for easier distribution in low to middle income countries.

Impact of Closed System Transfer Device (CSTD) Handling Procedure for Low-Transfer-Volume Dose Preparation of Biologic Drug Products

Many challenges have been identified for ensuring compatibility of closed system transfer devices (CSTDs) with biologic drug products. One challenge is large hold-up volumes (HUVs) of CSTD components, which can be especially problematic with early-stage biologics when low transfer volumes smaller than the nominal fill volume may be used to achieve a wide range of doses with a single drug product configuration. Here, we identified possible CSTD handling techniques during dose preparation of a drug product requiring small volume transfers during reconstitution, intermediate dilution, and dilution in an IV bag, and systematically evaluated the impact of these handling procedures on the ability to deliver an accurate dose to the next step. We show that small changes to CSTD procedures can have a major impact on dose accuracy, depending on both CSTD HUVs and drug product-specific transfer volumes. We demonstrate that it is possible to craft CSTD instructions for use to mitigate these issues, and that the dose accuracy for specific drug product/CSTD combinations can be estimated using theoretical equations. Finally, we explored potential downsides of these mitigations. Our results emphasize key factors for consideration by both drug and CSTD manufacturers when assessing compatibility and providing CSTD instructions for use with biologics requiring low transfer volumes during dose preparation.

Comparison of the Protective Effect of Polysorbates, Poloxamer and Brij on Antibody Stability Against Different Interfaces

Therapeutic proteins and antibodies are exposed to a variety of interfaces during their lifecycle, which can compromise their stability. Formulations, including surfactants, must be carefully optimized to improve interfacial stability against all types of surfaces. Here we apply a nanoparticle-based approach to evaluate the instability of four antibody drugs against different solid-liquid interfaces characterized by different degrees of hydrophobicity. We considered a model hydrophobic material as well as cycloolefin-copolymer (COC) and cellulose, which represent some of the common solid-liquid interfaces encountered during drug production, storage, and delivery. We assess the protective effect of polysorbate 20, polysorbate 80, Poloxamer 188 and Brij 35 in our assay and in a traditional agitation study. While all nonionic surfactants stabilize antibodies against the air-water interface, none of them can protect against hydrophilic charged cellulose. Polysorbates and Brij increase antibody stability in the presence of COC and the model hydrophobic interface, although to a lesser extent compared to the air-water interface, while Poloxamer 188 has a negligible stabilizing effect against these interfaces. These results highlight the challenge of fully protecting antibodies against all types of solid-liquid interfaces with traditional surfactants. In this context, our high-throughput nanoparticle-based approach can complement traditional shaking assays and assist in formulation design to ensure protein stability not only at air-water interfaces, but also at relevant solid-liquid interfaces encountered during the product lifecycle.

Interfacial Adsorption Controls Particle Formation in Antibody Formulations Subjected to Extensional Flows and Hydrodynamic Shear

During their manufacturing and delivery to patients, therapeutic proteins are commonly exposed to various interfaces and to hydrodynamic shear forces. Although adsorption of proteins to solid-liquid interfaces is known to foster formation of protein aggregates and particles, the impact of shear remains controversial, in part because of experimental challenges in separating the effects of shear from those caused by simultaneous exposure to interfaces. Extensional flows (occurring when solutions flow through sudden contractions) exert localized elongational forces that have been suspected to be damaging to proteins. In this work, we measured aggregation and particle formation in formulations of polyclonal and monoclonal antibodies subjected to extensional flow, high shear (105 s-1) and exposure to stainless-steel/water interfaces. Modification of the surface charge at the stainless steel/water interface changed protein adsorption characteristics without altering shear profiles, enabling shear and interfacial interactions to be separated. Even under conditions where antibodies were subjected to high hydrodynamic shear and extensional flow, production of subvisible particles could be inhibited by modifying the stainless-steel surface charge to minimize antibody adsorption. Digital images of particles recorded by flow imaging microscopy (FIM) and analyzed with machine learning algorithms were consistent with a particle formation mechanism by which antibodies adsorb and aggregate at the stainless-steel/water interface and subsequently form particles when shear displaces the interfacial aggregates, transporting them into the bulk solution. Topographical differences measured using atomic force microscopy (AFM) supported the proposed mechanism by showing reduced levels of protein adsorption on surface-charge-modified stainless-steel.

Predicting Formulation Conditions During Ultrafiltration and Dilution to Drug Substance Using a Donnan Model with Homology-Model Based Protein Charge

In the manufacturing of therapeutic monoclonal antibodies (mAbs), the final steps of the purification process are typically ultrafiltration/diafiltration (UF/DF), dilution, and conditioning. These steps are developed such that the final drug substance (DS) is formulated to the desired mAb, buffer, and excipient concentrations. To develop these processes, process and formulation development scientists often perform experiments to account for the Gibbs-Donnan and volume-exclusion effects during UF/DF, which affect the output pH and buffer concentration of the UF/DF process. This work describes the development of an in silico model for predicting the DS pH and buffer concentration after accounting for the Gibbs-Donnan and volume-exclusion effects during the UF/DF operation and the subsequent dilution and conditioning steps. The model was validated using statistical analysis to compare model predictions against experimental results for nine molecules of varying protein concentrations and formulations. In addition, our results showed that the structure-based in silico approach used to calculate the protein charge was more accurate than a sequence-based approach. Finally, we used the model to gain fundamental insights about the Gibbs-Donnan effect by highlighting the role of the protein charge concentration (the protein concentration multiplied with protein charge at the formulation pH) on the Gibbs-Donnan effect. Overall, this work demonstrates that the Gibbs-Donnan and volume-exclusions effects can be predicted using an in silico model, potentially alleviating the need for experiments.

Insights into the Stabilization of Interferon Alpha by Two Surfactants Revealed by STD-NMR Spectroscopy

Surfactants are commonly used in biopharmaceutical formulations to stabilize proteins against aggregation. However, the choice of a suitable surfactant for a particular protein is decided mostly empirically, and their mechanism of action on molecular level is largely unknown. Here we show that a straightforward label-free method, saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy, can be used to detect protein-surfactant interactions in formulations of a model protein, interferon alpha. We find that polysorbate 20 binds with its fatty acid to interferon, and that the binding is stronger at pH closer to the isoelectric point of the protein. In contrast, we did not detect interactions between poloxamer 407 and interferon alpha. Neither of the two surfactants affected the tertiary structure and the thermal stability of the protein as evident from circular dichroism and nanoDSF measurements. Interestingly, both surfactants inhibited the formation of subvisible particles during long-term storage, but only polysorbate 20 reduced the amount of small soluble aggregates detected by size-exclusion chromatography. This proof-of-principle study demonstrates how STD-NMR can be employed to quickly assess surfactant-protein interactions and support the choice of surfactant in protein formulation.

Characterization of Recombinantly-Expressed Hydrolytic Enzymes from Chinese Hamster Ovary Cells: Identification of Host Cell Proteins that Degrade Polysorbate

Enzymatic hydrolysis of polysorbate in drug products is a major challenge for the biopharmaceutical industry. Polysorbate hydrolysis caused by host cell proteins (HCPs) co-purified during bioprocessing can reduce the protective effects of the surfactant for the active pharmaceutical ingredient and cause the accumulation of low-solubility degradation products over the long-term storage. The identities of such HCPs are elusive due to their extremely low concentrations after the efficient purification processes of most biopharmaceuticals. In this work, 20 enzymes-selected for their known or putative hydrolytic activity and potential to degrade polysorbate-were recombinantly expressed, purified, and characterized via orthogonal methods. First, these recombinant HCPs were assessed for hydrolytic activity against a fluorogenic esterase substrate in a recently-developed, high-throughput assay. Second, these HCPs were screened for hydrolytic activity against polysorbate in a representative mAb formulation. Third, HCPs that displayed hydrolytic activities in the first two assays were subjected to more detailed characterization of their enzyme kinetics against polysorbates. Finally, these HCPs were evaluated for substrate specificity towards different sub-species of polysorbates. This work provides critical new insights for targeted LC-MS/MS approaches for identification of relevant polysorbate-degrading enzymes and supports improvements to remove such HCPs, including knockouts or targeted removal during purification.

Protein-Surfactant and Protein-Protein Interactions During Freeze and Thaw: A Small-Angle Neutron Scattering Study of Lysozyme Solutions with Polysorbate and Poloxamer

Protein structural changes during freezing and subsequent thawing are of great importance to a variety of biopharmaceutical applications. In this work, we studied the influence of non-ionic surfactants (polysorbate 20 and poloxamer 188) on protein structural changes during freeze and thaw using lysozyme as a model protein. Small-angle neutron scattering was employed to characterize protein structures in both liquid and frozen solution states. The results show minimal impact of polysorbate 20 on lysozyme structures during freeze and thaw using practically relevant concentrations. Polysorbate 20 used at 0.04% (w/w) completely prevents freeze-induced aggregation of lysozyme. Poloxamer 188 seems to interact with lysozyme; when applied at high concentrations (10% w/w), such interaction prevents protein crowding or close packing typically associated with freeze concentration. Despite such interactions, lysozyme aggregation is observed with 10% (w/w) of poloxamer 188 during freezing, although the aggregation is reversed upon thawing.

Exploring the Protein Stabilizing Capability of Surfactants Against Agitation Stress and the Underlying Mechanisms

The application of surfactants in liquid protein formulation is a common practice to protect proteins from liquid-air interface-induced protein aggregation. Typically, Polysorbate 20 or 80 are used, but degradation of these surfactants can result in particle formation and/or protein degradation. The purpose of the current study was to directly compare three alternative protein stabilizing molecules - Poloxamer 188, hydroxypropyl-cyclodextrin and a trehalose-based surfactant - to Polysorbate 80 for their capacities to reduce agitation-induced protein aggregation and particle formation; and furthermore, investigate their underlying protein stabilizing mechanisms. To this end, a small-volume, rapid agitation stress approach was used to quantify the molecules' abilities to stabilize two model proteins. This assay was presented to be a powerful tool to screen the protein stabilizing capability of surfactants using minimum of material and time. SEC, turbidity measurements and particle analysis showed an efficient protein stabilization of all tested surfactants as well as cyclodextrin. STD-NMR and dynamic surface tension measurements indicated the competitive surface adsorption to be the main protein stabilizing mechanism of the three surfactants tested. It might also play a role to some extent in the protein stabilization by HPβCD. However, additional mechanisms might also contribute to protein stabilization leaving room for further investigations.

A Systematic Approach to Evaluating Closed System Drug-Transfer Devices during Drug Product Development

The use of Closed System Drug-Transfer Devices (CSTDs) has increased significantly in recent years due to NIOSH and USP recommendations to use them during preparation of hazardous drugs. Mechanistic and material differences between CSTDs and traditional in-use components warrant an assessment of their impact on product quality and dosing accuracy. Using a combination of prevalent CSTDs with biologic molecules, we performed an extensive assessment of the effect of using CSTDs for dose preparation and observed no negative impact on product quality attributes. Additionally, we found that the CSTD hold-up volume is 2 to 4-fold higher than conventional in-use components and exhibited a strong dependence on the CSTD brand used. We also found that the CSTD brand and dosing volume have a major influence on dosing accuracy with suboptimal protein recovery at very low dosing volumes. We identified entrapment of product in the CSTD spike as the root cause for this sub-optimal recovery and found that flushing the CSTD spike with a brand-new syringe and not the dosing syringe aided in complete protein recovery. Taken together we present a systematic approach to evaluate the risks and impact of CSTD to drug product quality, dose preparation, and dosing accuracy.

Particles in Biopharmaceutical Formulations, Part 2: An Update on Analytical Techniques and Applications for Therapeutic Proteins, Viruses, Vaccines and Cells

Particles in biopharmaceutical formulations remain a hot topic in drug product development. With new product classes emerging it is crucial to discriminate particulate active pharmaceutical ingredients from particulate impurities. Technical improvements, new analytical developments and emerging tools (e.g., machine learning tools) increase the amount of information generated for particles. For a proper interpretation and judgment of the generated data a thorough understanding of the measurement principle, suitable application fields and potential limitations and pitfalls is required. Our review provides a comprehensive overview of novel particle analysis techniques emerging in the last decade for particulate impurities in therapeutic protein formulations (protein-related, excipient-related and primary packaging material-related), as well as particulate biopharmaceutical formulations (virus particles, virus-like particles, lipid nanoparticles and cell-based medicinal products). In addition, we review the literature on applications, describe specific analytical approaches and illustrate advantages and drawbacks of currently available techniques for particulate biopharmaceutical formulations.

Plate Reader-Based Analytical Method for the Size Distribution of Submicron-Sized Protein Aggregates Using Three-Dimensional Homodyne Light Detection

The assessment of aggregates is essential in biopharmaceutical development. Although submicron-sized aggregates are considered to have a potential immunogenicity risk, analytical techniques are limited. In this study, we present a new analytical technique using three-dimensional homodyne light detection (3D-HLD). In this system, submicron-sized particles are quantified by combining the reflected light detection of each particle by high-speed 3D scan and then enhancing the amplitude of the reflected light using HLD. The particle concentrations and size distributions of human tetanus immune globulin (TIG) aggregates generated by stirring were measured using 3D-HLD. Both concentrations and distributions were comparable to those obtained via resonant mass measurement (RMM), a technique commonly used for submicron-sized particle measurement. Aiming at feasibility assessment of 3D-HLD for the high-through-put formulation development, 30 formulations of TIG and rituximab under agitation stress were analyzed by 3D-HLD. The results showed that 3D-HLD can automatically and simultaneously assess the aggregate concentrations and size distributions of at least 90 samples. This study demonstrates that 3D-HLD can be used for submicron-sized aggregate analysis as an orthogonal method to RMM and also as a screening tool during formulation development.

Identification and Characterization of Polysorbate-Degrading Enzymes in a Monoclonal Antibody Formulation

Degradation of polysorbate (PS) by hydrolytically active host cell proteins (HCPs) in drug products may impair the protein-stabilizing properties of PS and lead to the formation of particles due to the accumulation of poorly soluble free fatty acids upon long-term storage. The identification of the causative enzymes is challenging due to their low-abundance even when using state-of-the-art instrumentation and workflows. To overcome these challenges, we developed a rigorous enrichment strategy for HCPs, utilizing both Protein A and anti-HCP affinity chromatography, which facilitated the in-depth characterization of the HCP population in a monoclonal antibody formulation prone to PS hydrolysis. Based on the HCPs identified by liquid chromatography coupled to tandem mass spectrometry, a number of enzymes annotated as hydrolases were recombinantly expressed and characterized in terms of polysorbate degradation. Among the selected candidates, Lipoprotein Lipase, Lysosomal Acid Lipase (LIPA) and Palmitoyl-Protein Thioesterase 1 (PPT1) exhibited notable activity towards PS. To our knowledge, this is the first report to identify LIPA and PPT1 as residual HCPs that can contribute to PS degradation in a biological product.

Stability of antibody drug conjugate formulations evaluated using solid-state hydrogen-deuterium exchange mass spectrometry

Antibody drug conjugates (ADCs) have been at the forefront in cancer therapy due to their target specificity. All the FDA approved ADCs are developed in lyophilized form to minimize instability associated with the linker that connects the cytotoxic drug and the antibody during shipping and storage. We present here solid-state hydrogen-deuterium exchange with mass spectrometric analysis (ssHDX-MS) as a tool to analyze protein structure and matrix interactions for formulations of an ADC with and without commonly used excipients. We compared results of the ssHDX-MS with accelerated stability results using size-exclusion chromatography and determined that the former technique was able to successfully identify the destabilizing effects of mannitol and polysorbate 80. In comparison, Fourier-transform infrared spectroscopy results were inconclusive. The agreement between ssHDX-MS and stressed stability studies supports the potential of ssHDX-MS as a method of predicting relative stability of different formulations.

Blinding Approaches for Large Clinical Trials Involving Sub-Cutaneous Administration of Biologicals - A CMC Perspective

A well-controlled clinical trial is one of the critical steps to evaluate the efficacy and safety of novel medicaments. The use of a placebo is employed in several types of clinical trials in order to set a baseline against which the efficacy of the investigational drug is evaluated. An ideal placebo should match the final formulation as close as possible such that the patient/health care providers are unable to identify any difference. This is difficult for high concentration biologic intended for subcutaneous administration, mainly because of their color and viscosity. Currently, the challenge is overcome by using opaque labels or by unblinded pharmacists, both solutions are expensive. The present study provides an efficient alternative where a protein excipient (recombinant albumin) is used to prepare a placebo for biologicals. We have demonstrated that the use of recombinant albumin can match the color of the active when used in the right quantity. The evaluated solution is highly flexible and has the potential to match the color of different biopharmaceuticals at different concentrations/formulations.

A Rapid, Small-Volume Approach to Evaluate Protein Aggregation at Air-Water Interfaces

Non-native protein aggregation is a common concern for biopharmaceuticals. A given protein may aggregate through a variety of mechanisms that depend on solution and physico-chemical stress conditions. A thorough evaluation of aggregation behavior for a protein under all conditions of interest is necessary to ensure drug safety and efficacy. This work introduces a rapid, small-volume approach to evaluate protein aggregation propensity upon exposure to air-water interfaces (AWI). A microtensiometer apparatus is used to aerate a small volume of a protein solution with microbubbles for short periods of time (≤10 s). Sub-visible particles that form are captured and analyzed using backgrounded membrane imaging. This allows one to capture all particles in the solution while being sample sparing. The surface-mediated aggregation of two model monoclonal antibodies (MAbs) and a globular protein (aCgn) was tested as a function of pH and temperature. Temperature had a negligible effect under the rapid interface turnover time scales with this technique. Electrostatic protein-protein interactions, mediated by pH changes, were more influential for particle formation via AWI. Nonionic surfactants substantially reduced particle formation for all MAb solutions, but not aCgn. The results are contrasted with expectations when exposing samples to much larger air-water interfacial stress.

An Industry Perspective on Compatibility Assessment of Closed System Drug-Transfer Devices for Biologics

The Formulation Workstream of the BioPhorum Development Group (BPDG), an industry-wide consortium, has identified the increased use of closed system drug-transfer devices (CSTDs) with biologics, without an associated compatibility assessment, to be of significant concern. The use of CSTDs has increased significantly in recent years due to the recommendations by NIOSH and USP that they be used during preparation and administration of hazardous drugs. While CSTDs are valuable in the healthcare setting to reduce occupational exposure to hazardous compounds, these devices may present particular risks that must be adequately assessed prior to use to ensure their compatibility with specific types of drug products, such as biologic drugs, which may be sensitive. The responsibility of ensuring quality of biologic products through preparation and administration to the patient lies with the drug product sponsor. Due to the significant number of marketed CSTD systems, and the large variety of components offered for each system, a strategic, risk-based approach to assessing compatibility is recommended herein. In addition to traditional material compatibility, assessment of CSTD compatibility with biologics should consider additional parameters to address specific CSTD-related risks. The BPDG Formulation Workstream has proposed a systematic risk-based evaluation approach as well as a mitigation strategy for establishing suitability of CSTDs for use.

Application of a High Throughput and Automated Workflow to Therapeutic Protein Formulation Development

Rapid and efficient formulation development is critical to successfully bringing therapeutic protein drug products into a competitive market under increasingly aggressive timelines. Conventional application of high throughput techniques for formulation development have been limited to lower protein concentrations, which are not applicable to late stage development of high concentration therapeutics. In this work, we present a high throughput (HT) formulation workflow that enables screening at representative concentrations via integration of a micro-buffer exchange system with automated analytical instruments. The operational recommendations associated with the use of such HT systems as well as the efficiencies gained (reduction in hands-on time and run time by over 70% and 30%, respectively), which enable practical characterization of an expanded formulation design space, are discussed. To demonstrate that the workflow is fit for purpose, the formulation properties and stability profiles (SEC and CEX) from samples generated by the HT workflow were compared to those processed by ultrafiltration/diafiltration, and the results were shown to be in good agreement. This approach was further applied to two case studies, one focused on a formulation screen that studied the effects of pH and excipient on viscosity and stability, and the other focused on selection of an appropriate viscosity mimic solution for a protein product.

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

The use of monoclonal antibodies (mAbs) for the treatment of a variety of diseases is rapidly growing each year. Many mAbs are administered intravenously using i.v. bags containing 0.9% NaCl (normal saline). We studied the aggregation propensity of these antibody solutions in saline and compared it with a low ionic strength formulation buffer. The mAb studied in this work is prone to aggregate, and is known to form a viscoelastic network at the air-solution interface. We observed that this interfacial elasticity increased when formulated in saline. In the bulk, the mAbs exhibited a tendency to self-associate that was higher in saline. We also studied the aggregation of the mAbs in the presence of polysorbate-20, typically added to formulations to mitigate interfacial aggregation. We observed that with surfactants, the presence of salt in the buffer led to a greater mAb adsorption at the interface and resulted in the formation of more particulate aggregates. Our results show that the addition of salt to the buffer led to differences in the interfacial aggregation in mAb formulations, showing that stress studies used to screen for mAb aggregation intended for i.v. administration should be performed in conditions representative of their intended route of administration.

Glass Leachables as a Nucleation Factor for Free Fatty Acid Particle Formation in Biopharmaceutical Formulations

Surfactants are essential components in protein formulations protecting them against interfacial stress. One of the current industry-wide challenges is enzymatic degradation of parenteral surfactants such as polysorbate 20 (PS20) and polysorbate 80, which leads to the accumulation of free fatty acids (FFAs) potentially forming visible particles over the drug product shelf-life. While the concentration of FFAs can be quantified, the time point of particle formation remains unpredictable. In this work, we studied the influence of glass leachables as nucleation factors for FFA particle formation. We demonstrate the feasibility of nucleation of FFA particles in the presence of inorganic salts like NaAlO₂ and CaCl₂ simulating relevant glass leachables. We further demonstrate FFA particle formation depending on relevant aluminum concentrations. FFA particle formation was subsequently confirmed with lauric/myristic acid in the presence of different quantities and compositions of glass leachables obtained by several sterilization cycles using different types of glass vials. We further verified the formation of particles in aged protein formulation containing degraded PS20 through the spiking of glass leachables. Particles were characterized as a complex of glass leachables, such as aluminum and FFAs. Based on our findings, we propose a likely pathway for FFA particle formation that considers specific nucleation factors.

Comparison of Strategies in Development and Manufacturing of Low Viscosity, Ultra-High Concentration Formulation for IgG1 Antibody

Monoclonal antibodies requiring higher doses for exerting therapeutic effect but having lower stability, are administered as dilute infusions, or as two (low concentration) injections both resulting in reduced patient compliance. Present research summarizes impact of manufacturing conditions on ultra-high concentration (≥150 mg/mL) IgG1 formulation, which can be administered as one subcutaneous injection. IgG1 was concentrated to ~200 mg/mL using tangential flow filtration (TFF). Alternatively, spray dried (SPD) and spray freeze dried (SFD) IgG1, was reconstituted in 30%v/v propylene glycol to form ultra-high concentration (~200 mg/mL) injectable formulation. Reconstituted, SPD and SFD IgG1 formulations, increased viscosity beyond an acceptable range for subcutaneous injections (<20 cP). Formulations developed by reconstitution of SPD IgG1, demonstrated increase in high and low molecular weight impurities, at accelerated and stressed conditions. Whereas, the stability data suggested reconstituted SFD IgG1 was comparable to control IgG1 formulation concentrated by TFF. Also, formulation of IgG1 diafiltered with proline using TFF, reduce viscosity from ~21.9 cP to ~11 cP at 25 °C and had better stability. Thus, conventional TFF technique stands to be one of the preferred methods for manufacturing of ultra-high concentration IgG1 formulations. Additionally, SFD could be an alternative method for long term storage of IgG1 in a dry powder state.

Protein-protein interactions and water activity coefficients can be used to aid a first excipient choice in protein formulations

With respect to all biopharmaceuticals marketed to date, monoclonal antibodies represent the largest fraction with more than 48% market share (2012). However, the development of biopharmaceutical formulations is a challenging task, and time-consuming and cost-intensive high-throughput screenings are still state-of-the-art in formulation design. These screening techniques are almost exclusively based on heuristic decisions thus the benefit in terms of mechanistic understanding is often unclear. It requires novel, physical-sound methods to enhance/optimize future formulation development, ideally by understanding molecular interactions in these complex solutions. A suitable and evaluated measure-of-choice to characterize protein-protein interactions in aqueous protein solutions is the second osmotic virial coefficient B₂₂ which can be measured using static light scattering techniques. Furthermore B₂₂ can be modeled/predicted via the extended mxDLVO model for protein-protein interactions in the presence of single excipients and excipient-mixtures. Building up on this approach, giving an additional insight into water-water and water-excipient interactions, the thermodynamic equation-of-state ePC-SAFT is used to calculate water activity coefficients in the presence of excipient-mixtures. Immunoglobulin G (IgG) was chosen as a model protein to predict B₂₂-values for IgG in the presence of model excipient-mixtures (trehalose-NaCl, l-histidine-trehalose, l-histidine-NaCl). The combination of water activity coefficients and B₂₂ allows to quickly identify a first guess on suitable formulation conditions that then can be further evaluated with existing methods/knowledge.