Impact of dextran on thermal properties, product quality attributes, and monoclonal antibody stability in freeze-dried formulations

Protecting Lyophilized Escherichia coli Adenylate Kinase

Drying protein-based drugs, usually via lyophilization, can facilitate storage at ambient temperature and improve accessibility but many proteins cannot withstand drying and must be formulated with protective additives called excipients. However, mechanisms of protection are poorly understood, precluding rational formulation design. To better understand dry proteins and their protection, we examine Escherichia coli adenylate kinase (AdK) lyophilized alone and with the additives trehalose, maltose, bovine serum albumin, cytosolic abundant heat soluble protein D, histidine, and arginine. We apply liquid-observed vapor exchange NMR to interrogate the residue-level structure in the presence and absence of additives. We pair these observations with differential scanning calorimetry data of lyophilized samples and AdK activity assays with and without heating. We show that the amino acids do not preserve the native structure as well as sugars or proteins and that after heating the most stable additives protect activity best.

Sweet corn phytoglycogen dendrimers as a lyoprotectant for dry-state protein storage

Protein biotherapeutics typically require expensive cold-chain storage to maintain their fold and function. Packaging proteins in the dry state via lyophilization can reduce these cold-chain requirements. However, formulating proteins for lyophilization often requires extensive optimization of excipients that both maintain the protein folded state during freezing and drying (i.e., "cryoprotection" and "lyoprotection"), and form a cake to carry the dehydrated protein. Here we show that sweet corn phytoglycogens, which are glucose dendrimers, can act as both a protein lyoprotectant and a cake-forming agent. Phytoglycogen (PG) dendrimers from 16 different maize sources (PG1-16) were extracted via ethanol precipitation. PG size was generally consistent at ~70-100 nm for all variants, whereas the colloidal stability in water, protein contaminant level, and maximum density of cytocompatibility varied for PG1-16. 10 mg/mL PG1, 2, 9, 13, 15, and 16 maintained the activity of various proteins, including green fluorescent protein, lysozyme, β-galactosidase, and horseradish peroxidase, over a broad range of concentrations, through multiple rounds of lyophilization. PG13 was identified as the lead excipient candidate as it demonstrated narrow dispersity, colloidal stability in phosphate-buffered saline, low protein contaminants, and cytocompatibility up to 10 mg/mL in NIH3T3 cell cultures. All dry protein-PG13 mixtures had a cake-like appearance and all frozen protein-PG13 mixtures had a Tg' of ~ -26°C. The lyoprotection and cake-forming properties of PG13 were density-dependent, requiring a minimum density of 5 mg/mL for maximum activity. Collectively these data establish PG dendrimers as a new class of excipient to formulate proteins in the dry state.

Comparison of Sucrose and Trehalose for Protein Stabilization Using Differential Scanning Calorimetry

The disaccharide trehalose is generally acknowledged as a superior stabilizer of proteins and other biomolecules in aqueous environments. Despite many theories aiming to explain this, the stabilization mechanism is still far from being fully understood. This study compares the stabilizing properties of trehalose with those of the structurally similar disaccharide sucrose. The stability has been evaluated for the two proteins, lysozyme and myoglobin, at both low and high temperatures by determining the glass transition temperature, Tg, and the denaturation temperature, Tden. The results show that the sucrose-containing samples exhibit higher Tden than the corresponding trehalose-containing samples, particularly at low water contents. The better stabilizing effect of sucrose at high temperatures may be explained by the fact that sucrose, to a greater extent, binds directly to the protein surface compared to trehalose. Both sugars show Tden elevation with an increasing sugar-to-protein ratio, which allows for a more complete sugar shell around the protein molecules. Finally, no synergistic effects were found by combining trehalose and sucrose. Conclusively, the exact mechanism of protein stabilization may vary with the temperature, as influenced by temperature-dependent interactions between the protein, sugar, and water. This variability can make trehalose to a superior stabilizer under some conditions and sucrose under others.

Effect of Annealing on Visible-Bubble Formation and Stability Profiles of Freeze-Dried High Concentration Omalizumab Formulations

In the clinical application of freeze-dried highly concentrated omalizumab formulations, extensive visible bubbles (VBs) can be generated and remain for a long period of time in the reconstitution process, which greatly reduces the clinical use efficiency. It is necessary to understand the forming and breaking mechanism of VBs in the reconstitution process, which is a key factor for efficient and safe administration of biopharmaceutical injection. The effects of different thermal treatments on the volume of VBs and stability of omalizumab, mAb-1, and mAb-2 were investigated. The internal microvoids of the cake were characterized by scanning electron microscopy and mercury intrusion porosimetry. Electron paramagnetic resonance was applied to obtain the molecular mobility of the protein during annealing. A large number of VBs were generated in the reconstitution process of unannealed omalizumab and remained for a long period of time. When annealing steps were added, the volume of VBs was dramatically reduced. When annealed at an aggressive temperature (i.e., -6 °C), although the volume of VBs decreased, the aggregation and acidic species increased significantly. Thus, our observations highlight the importance of setting an additional annealing step with a suitable temperature, which contributes to reducing the VBs while maintaining the stability of the high concentration freeze-dried protein formulation.

The interplay between trehalose and dextran as spray drying precursors for cationic liposomes

Successful oral delivery of liposomes requires formulations designed to withstand harsh gastrointestinal conditions, e.g., by converting to solid-state followed by loading into gastro-resistant delivery devices. The hypothesis was that the use of dextran-trehalose mixtures for spray drying would improve the rehydration kinetics of dried liposomes. The objectives were to determine the protective capacity of trehalose-dextran dehydration precursors and to increase the concentration of liposomes in the dry formulation volume. The study successfully demonstrated that 8.5% dextran combined with 76.5% trehalose protected CAF®04 liposomes during drying, with the liposome content maintained at 15% of the dry powder. Accordingly, the rehydration kinetics were slightly improved in formulations containing up to 8.5% dextran in the dry powder volume. Additionally, a 2.4-fold increase in lipid concentration (3 mM vs 7.245 mM) was achieved for spray dried CAF®04 liposomes. Ultimately, this study demonstrates the significance of trehalose as a primary carrier during spray drying of CAF®04 liposomes and highlights the advantage of incorporating small amounts of dextran to tune rehydration kinetics of spray-dried liposomes.

Stabilization effects of saccharides in protein formulations: A review of sucrose, trehalose, cyclodextrins and dextrans

Saccharides are a popular group of stabilizers in liquid, frozen and freeze dried protein formulations. The current work reviewed the stabilization mechanisms of three groups of saccharides: (i) Disaccharides, specifically sucrose and trehalose; (ii) cyclodextrins (CDs), a class of cyclic oligosaccharides; and (iii) dextrans, a class of polysaccharides. Compared to sucrose, trehalose exhibits a more pronounced preferential exclusion effect in liquid protein formulations, due to its stronger interaction with water molecules. However, trehalose obtains higher phase separation and crystallization propensity in frozen solutions, resulting in the loss of its stabilization function. In lyophilized formulations, sucrose has a higher crystallization propensity. Besides, its glass matrix is less homogeneous than that of trehalose, thus undermining its lyoprotectant function. Nevertheless, the hygroscopic nature of trehalose may result in high water absorption upon storage. Among all the CDs, the β form is believed to have stronger interactions with proteins than the α- and γ-CDs. However, the stabilization effect, brought about by CD-protein interactions, is case-by-case - in some examples, such interactions can promote protein destabilization. The stabilization effect of hydroxypropyl-β-cyclodextrin (HPβCD) has been extensively studied. Due to its amphiphilic nature, it can act as a surface-active agent in preventing interfacial stresses. Besides, it is a dual functional excipient in freeze dried formulations, acting as an amorphous bulking agent and lyoprotectant. Finally, dextrans, when combined with sucrose or trehalose, can be used to produce stable freeze dried protein formulations. A strong stabilization effect can be realized by low molecular weight dextrans. However, the terminal glucose in dextrans yields protein glycation, which warrants extra caution during formulation development.

Thermal stability of exenatide encapsulated in stratified dissolving microneedles during storage

As low-temperature storage and transportation of peptides require high costs, improving the dosage form of peptides can reduce costs. We developed a thermostable and fast-releasing stratified dissolving microneedle (SDMN) system for delivering exenatide (EXT) to patients with type 2 diabetes. Among the tested polymers, dextran and polyvinyl alcohol (PVA) were the best at stabilizing EXT under high-temperature storage for 9 weeks. The two polymers possess a relatively high glass transition temperature (T_g) and weak hydrogen bonding between PVA and EXT. Additionally, zinc sulfate (ZnSO₄) had a stabilizing effect on EXT among the selected stabilizers, suggesting that EXT formed a dimer after coordination with zinc ions (Zn²⁺). In addition, the denaturation temperature (T_m) of EXT was increased by adding ZnSO₄, thus stabilizing EXT. Accordingly, SDMNs consisting of a tip layer (dextran encapsulating the Zn²⁺-EXT complex) and a base layer (PVA) were fabricated. Within 2 min of implantation, the EXT loaded on the patch was quickly released into the skin. Transdermal pharmacokinetics studies showed that manufactured SDMNs generated comparable efficacy to subcutaneous injection. Significantly, the remaining EXT amount was not significantly different under storage at 40 °C and -20 °C for 3 months, supporting that the SDMN system had excellent delivery efficiency and stability, thus reducing the dependence on the cold chain.

Recent progress in drying technologies for improving the stability and delivery efficiency of biopharmaceuticals

Background

Most biopharmaceuticals are developed in liquid dosage forms that are less stable than solid forms. To ensure the stability of biopharmaceuticals, it is critical to use an effective drying technique in the presence of an appropriate stabilizing excipient. Various drying techniques are available for this purpose, such as freeze drying or lyophilization, spray drying, spray freeze-drying, supercritical fluid drying, particle replication in nonwetting templates, and fluidized bed drying.

Area covered

In this review, we discuss drying technologies and their applications in the production of stable solid-state biopharmaceuticals, providing examples of commercially available products or clinical trial formulations. Alongside this, we also review how different analytical methods may be utilized in the evaluation of aerosol performance and powder characteristics of dried protein powders. Finally, we assess the protein integrity in terms of conformational and physicochemical stability and biological activity.

Expert opinion

With the aim of treating either infectious respiratory diseases or systemic disorders, inhaled biopharmaceuticals reduce both therapeutic dose and cost of therapy. Drying methods in the presence of optimized protein/stabilizer combinations, produce solid dosage forms of proteins with greater stability. A suitable drying method was chosen, and the process parameters were optimized based on the route of protein administration. With the ongoing trend of addressing deficiencies in biopharmaceutical production, developing new methods to replace conventional drying methods, and investigating novel excipients for more efficient stabilizing effects, these products have the potential to dominate the pharmaceutical industry in the future.

Stabilizing vaccines via drying: Quality by design considerations

Pandemics and epidemics are continually challenging human beings' health and imposing major stresses on the societies particularly over the last few decades, when their frequency has increased significantly. Protecting humans from multiple diseases is best achieved through vaccination. However, vaccines thermal instability has always been a hurdle in their widespread application, especially in less developed countries. Furthermore, insufficient vaccine processing capacity is also a major challenge for global vaccination programs. Continuous drying of vaccine formulations is one of the potential solutions to these challenges. This review highlights the challenges on implementing the continuous drying techniques for drying vaccines. The conventional drying methods, emerging technologies and their adaptation by biopharmaceutical industry are investigated considering the patented technologies for drying of vaccines. Moreover, the current progress in applying Quality by Design (QbD) in each of the drying techniques considering the critical quality attributes (CQAs), critical process parameters (CPPs) are comprehensively reviewed. An expert advice is presented on the required actions to be taken within the biopharmaceutical industry to move towards continuous stabilization of vaccines in the realm of QbD.

Effect of polymer addition on the physical properties of freeze-dried soup solid

The effect of polymers (gelatin, starch, and maltodextrin) on the physical properties of freeze-dried model soup (sodium chloride, sucrose, and monosodium glutamate) was investigated. The polymers were added to the soup solution at 1 or 3% (w/v), which was then freeze-dried at 25 or 50 °C. Gelatin and maltodextrin prevented crystallization of sodium chloride to a greater extent than starch under freezing. Freeze-drying was conducted above the freeze-concentrated glass transition temperature. Polymer addition prolonged drying time, but prevented structural deformation. Gelatin enhanced the physical strength of the freeze-dried solid more than starch and maltodextrin because of its gel-network. In a dissolution test, 1% gelatin, and 1 and 3% maltodextrin exhibited greater dissolution than the other samples. The drying rate was lower at 50 °C, with minor modifications to the other properties. From these results, it was concluded that 1% gelatin was useful as a physical stabilizer for freeze-dried soup.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05161-x.

Optimization of Heat-Resistance Technology for a Duck Hepatitis Lyophilized Live Vaccine

In this study, to improve the quality of a live attenuated vaccine for duck viral hepatitis (DHV), the lyophilization of a heat-resistant duck hepatitis virus vaccine was optimized. The optimized heat protectors were made of 10% sucrose, 1.2% pullulan, 0.5% PVP, and 1% arginine, etc., with a titer freeze-drying loss of ≤0.50 Lg. The vaccine product’s valence measurements demonstrated the following: the vaccine could be stored at 2–8 °C for 18 months with a virus titer loss ≤0.91 Lg; at 37 °C for 10 days with a virus valence loss ≤0.89 Lg; and at 45 °C for 3 days with a virus titer loss ≤0.90 Lg. Regarding safety, no deaths occurred in two-day-old ducklings immunized with a 10 times dose vaccine; their energy, diet, and weight gain were all normal, demonstrating that the DHV heat-resistant vaccines were safe for ducklings and did not cause any immune side effects. Duck viral hepatitis freeze-dried vaccine began to produce antibodies at 7 d after immunization, reached above 5.0 on 14 d, and reached above 7.0 on 21 d, showing a continuous upward trend. This indicates that duck viral hepatitis vaccine has a good immunogen level. The optimization of the freeze-drying process saves costs and also improves the quality of the freeze-drying products, which provides important theoretical and technical support for the further study of vaccine products.

Chitosan-dipotassium orthophosphate lyophilizate: a novel in situ thermogel carrier system of allogeneic platelet lysate growth factors

The clinical success of platelet-rich plasma (PRP) is constrained by its limited mechanical strength, rapid disintegration by lytic enzymes, and the consequent short-term release of bioactive growth factors (GFs). Recently, attempts to formulate PRP and other hemoderivatives, such as platelet lysate (PL) have been underway. The current study aimed to formulate allogeneic freeze-dried human platelet lysate (HPL) onto lyophilized chitosan - dipotassium hydrogen orthophosphate (CS/DHO) thermo-sensitive scaffolds. A systemic approach was employed to optimize freeze-drying (FD) procedures targeting predefined critical quality attributes (CQAs). Thermal behavior, vibrational spectroscopy, morphological and moisture content analyses were used to detect possible protein destabilization during formulation and suboptimal cake properties. The effect of CS/DHO concentrations on thermo-responsiveness and release kinetics were investigated. Finally, six-months stability and cytotoxicity studies were carried out. An optimized lyophilizate was attainable with residual moisture of less than 5% and thermoresponsive to 33 °C in less than 3 min. HPL proteins were sustainedly released over five days in a pH-sensitive manner. The stability study indicated plausible physical and biochemical stability. Cell viability testing supported the cytocompatibility of the system. Finally, the lyophilizate variant of CS/DHO thermogel overcomes limited storage stability previously posed as a challenge in freshly prepared thermogels. The developed system overcomes the drawbacks of currently used PRP treatment and provides a novel GF-rich scaffold for wound repair.

Calorimetric Investigation of the Relaxation Phenomena in Amorphous Lyophilized Solids

Studying the thermal history and relaxation of solid amorphous drug product matrices by calorimetry is a well-known approach, particularly in the context of correlating the matrix parameters with the long-term stability of freeze-dried protein drug products. Such calorimetric investigations are even more relevant today, as the application of new process techniques in freeze-drying (which strongly influence the thermal history of the products) has recently gained more interest. To revive the application of calorimetric methods, the widely scattered knowledge on this matter is condensed into a review and completed with new experimental data. The calorimetric methods are applied to recent techniques in lyophilization, such as controlled nucleation and aggressive/collapse drying. Phenomena such as pre-Tg events in differential scanning calorimetry and aging shoulders in isothermal microcalorimetry are critically reviewed and supplemented with data of freeze-dried products that have not been characterized with these methods before.

Comparing freeze drying and spray drying of interleukins using model protein CXCL8 and its variants

Spray-dried products, such as synthetic peptides and hormones, have already been approved by the U.S. Food and Drug Agency and the European Medicines Agency, while spray-dried antibodies or interleukins, are not yet available on the market. Concerning the latter group, knowledge on whether and how spray-drying (SD) can be performed without adversely affecting their biological activity is lacking. Accordingly, this study aimed at establishing a SD process (Büchi B-90 spray dryer) using three Interleukin-8 based proteins (7-74 kDa) that were dispersed in phosphate buffered saline to maintain their stability. A Box-Behnken Design of Experiments was conducted to identify the appropriate process parameters taking into account the thermal stability of interleukin-8. In parallel, a FD process was developed. Both powders were stored for up to 12 weeks. Powder characterization included residual moisture evaluation and the mean particle size of the SD powder was investigated with Laser Diffraction Analysis. The hydrodynamic volume was measured via size exclusion chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The secondary structure of the model proteins in the solid state was assessed with Fourier-transformation infrared spectroscopy for detecting the protein folding patterns and reconstituted with Circular Dichroism Spectroscopy. Finally, the binding affinity was studied with Surface Plasmon Resonance and Isothermal Fluorescence Titration, the protein stability with Chaotropic Unfolding, and the activity studies were carried out with the chemotaxis assay. The results showed that SD and FD powders with a residual moisture of less than 5 wt% were obtained. The interleukins showed no unfolding upon processing, neither in solid state nor reconstituted. Oligomerization was observed for FD, but not for SD interleukins. However, the unfolding, binding affinity and activity of all interleukins examined did not decrease in neither SD nor FD powders, even after 12 weeks of storage. Thus, it can be concluded that SD of interleukin formulations at outlet temperatures close to ambient temperature is a promising process for transferring them into a stable powder.

Stabilizers and their interaction with formulation components in frozen and freeze-dried protein formulations

This review aims to provide an overview of the current knowledge on protein stabilization during freezing and freeze-drying in relation to stress conditions commonly encountered during these processes. The traditional as well as refined mechanisms by which excipients may stabilize proteins are presented. These stabilizers encompass a wide variety of compounds including sugars, sugar alcohols, amino acids, surfactants, buffers and polymers. The rational selection of excipients for use in frozen and freeze-dried protein formulations is presented. Lyophilized protein formulations are generally multicomponent systems, providing numerous possibilities of excipient-excipient and protein-excipient interactions. The interplay of different formulation components on the protein stability and excipient functionality in the frozen and freeze-dried systems are reviewed, with discussion of representative examples of such interactions.

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.

Comparison of Techniques to Control Ice Nucleation during Lyophilization

Controlling ice nucleation during lyophilization of parenteral drug products increases the homogeneity of critical quality attributes, such as residual moisture, across drug product batches and shortens lyophilization cycle time. In the present study, we compare three mechanistically different techniques to control ice nucleation during the freezing step of lyophilization, which are referred to as “depressurization”, “partial vacuum”, and “ice fog” techniques. The techniques are compared with respect to their operational limitations and challenges. Installation considerations are also discussed. Using the aforementioned nucleation techniques, we investigated a monoclonal antibody formulation and an enzyme formulation at different protein concentrations using feasible nucleation temperatures and different vial formats and fill volumes. Samples were compared for solid state properties and other critical quality attributes on stability. When nucleated at the same temperature, the three techniques produced products with the same quality attributes and stability behavior. Under conditions resulting in micro-collapse, stability behavior can be different. We found that each technology had considerations for achieving robust nucleation. The present comparison may serve as guidance in selecting a nucleation method.