How sugars protect proteins in the solid state and during drying (review): Mechanisms of stabilization in relation to stress conditions

Rapid identity testing of antibody-based hot targeted radionuclide therapies by bio-layer interferometry

Targeted Radionuclide Therapies (TRT) involve the tailored combination of a therapeutic radionuclide and a targeting molecule, as for instance antibodies or fragments thereof. Despite their short shelf-life, these drug products must meet stringent regulatory standards before use. We introduce a novel, efficient method utilizing Bio-Layer Interferometry (BLI) for rapid identity testing of TRT drug products in less than five minutes. This approach not only reduces radioactive waste but also minimizes operator exposure to radiation. This label-free method has been successfully developed and validated for three different TRT products, ensuring compliance with Good Manufacturing Practices (GMP). Furthermore, we outline our strategic approach to the production and testing of custom biosensors for each product, firmly grounded in Quality-by-Design (QbD) principles.

Leucine as a moisture-protective excipient in spray-dried protein/trehalose formulation

The incorporation of leucine (Leu), a hydrophobic amino acid, into pharmaceutically relevant particles via spray-drying can improve the physicochemical and particulate properties, stability, and ultimately bioavailability of the final product. More specifically, Leu has been proposed to form a shell on the surface of spray-dried (SD) particles. The aim of this study was to explore the potential of Leu in the SD protein/trehalose (Tre) formulation to control the water uptake and moisture-induced recrystallization of amorphous Tre, using lysozyme (LZM) as a model protein. LZM/Tre (1:1, w/w) were dissolved in water with varied amounts of Leu (0 - 40%, w/w) and processed by spray-drying. The solid form, residual moisture content (RMC), hygroscopicity, and morphology of SD LZM/Tre/Leu powders were evaluated, before and after storage under 22°C/55% RH conditions for 90 and 180 days. The X-ray powder diffraction results showed that Leu was in crystalline form when the amount of Leu in the formulation was at least 20% (w/w). Thermo-gravimetric analysis and scanning electron microscopy results showed that 0%, 5%, and 10% Leu formulations led to comparable RMC and raisin-like round particles. In contrast, higher Leu contents resulted in a lower RMC and increased surface corrugation of the SD particles. Dynamic vapor sorption analysis showed that in the 0% Leu formulation, partial recrystallization of amorphous Tre to crystalline Tre·dihydrate occurred, and the addition of as little as 5% Leu could inhibit the recrystallization of amorphous Tre during the water sorption/desorption cycle. In addition, after storage, formulations with higher Leu contents resulted in less water uptake. Rather than recrystallization of amorphous Tre in 0%, 5%, and 10% Leu formulations, recrystallization of amorphous Leu was observed in both 5% and 10% Leu formulations after storage. In summary, our study demonstrated that the addition of Leu has the potential to reduce water uptake and inhibit moisture-induced recrystallization of amorphous Tre in the SD protein/Tre powder system.

Amino acids as stabilizers for lysozyme during the spray-drying process and storage

Amino acids (AAs) have been used as excipients in protein formulations both in solid and liquid state products due to their stabilizing effect. However, the mechanisms by which they can stabilize a protein have not been fully elucidated yet. The purpose of this study was to investigate the effect of AAs with distinct physicochemical properties on the stability of a model protein (lysozyme, LZM) during the spray-drying process and subsequent storage. Molecular descriptor based multivariate data analysis was used to select distinct AAs from the group of 20 natural AAs. Then, LZM and the five selected AAs (1:1 wt ratio) were spray-dried (SD). The solid form, residual moisture content (RMC), hygroscopicity, morphology, secondary/tertiary structure and enzymatic activity of LZM were evaluated before and after storage under 40 °C/75 % RH for 30 days. Arginine (Arg), leucine (Leu), glycine (Gly), tryptophan (Trp), aspartic acid (Asp) were selected because of their distinct properties by using principal component analysis (PCA). The SD LZM powders containing Arg, Trp, or Asp were amorphous, while SD LZM powders containing Leu or Gly were crystalline. Recrystallization of Arg, Trp, Asp and polymorph transition of Gly were observed after the storage under accelerated conditions. The morphologies of the SD particles vary upon the different AAs formulated with LZM, implying different drying kinetics of the five model systems. A tertiary structural change of LZM was observed in the SD powder containing Arg, while a decrease in the enzymatic activity of LZM was observed in the powders containing Arg or Asp after the storage. This can be attributed to the extremely basic and acidic conditions that Arg and Asp create, respectively. This study suggests that when AAs are used as stabilizers instead of traditional disaccharides, not only do classic vitrification theory and water replacement theory play a role, but the microenvironmental pH conditions created by basic or acidic AAs in the starting solution or during the storage of solid matter are also crucial for the stability of SD protein products.

Chromogenic fusion proteins as alternative textiles dyes

The widespread adoption of fast fashion has led to a significant waste problem associated with discarded textiles. Using proteins to color textiles can serve as a sustainable alternative to chemical dyes as well as reduce the demand for new raw materials. Here, we explore the use of chromogenic fusion proteins, consisting of a chromoprotein and a carbohydrate-binding module (CBM), as coloring agents for cellulose-based textiles such as cotton. We examined the color properties of chromoproteins AeBlue, SpisPink and Ultramarine alone and fused to CBM under various conditions. AeBlue, SpisPink and Ultramarine exhibited visible color between pH 4-9 and temperatures ranging from 4 to 45℃. Fusing CBM Clos from Clostridium thermocellum and CBM Ch2 from Trichoderma reesei to the chromoproteins had no effect on the chromoprotein color properties. Furthermore, binding assays showed that chromoprotein fusions did not affect binding of CBMs to cellulosic materials. Cotton samples bound with Ultramarine-Clos exhibited visible purple color that faded progressively over time as the samples dried. Applying 10% 8000 polyethylene glycol to cotton samples markedly preserved the color over extended periods. Overall, this work highlights the potential of chromoprotein-CBM fusions for textile dying which could be applied as a color maintenance technology or for reversible coloring of textiles for events or work wear, contributing to sustainable practices and introducing new creative opportunities for the industry.

Utilizing COVID-19 as a Model for Diagnostics Using an Electrochemical Sensor

This paper reports a rapid and sensitive sensor for the detection and quantification of the COVID-19 N-protein (N-PROT) via an electrochemical mechanism. Single-frequency electrochemical impedance spectroscopy was used as a transduction method for real-time measurement of the N-PROT in an immunosensor system based on gold-conjugate-modified carbon screen-printed electrodes (Cov-Ag-SPE). The system presents high selectivity attained through an optimal stimulation signal composed of a 0.0 V DC potential and 10 mV RMS-1 AC signal at 100 Hz over 300 s. The Cov-Ag-SPE showed a log response toward N-PROT detection at concentrations from 1.0 ng mL-1 to 10.0 μg mL-1, with a 0.977 correlation coefficient for the phase (θ) variation. An ML-based approach could be created using some aspects observed from the positive and negative samples; hence, it was possible to classify 252 samples, reaching 83.0, 96.2 and 91.3% sensitivity, specificity, and accuracy, respectively, with confidence intervals (CI) ranging from 73.0 to 100.0%. Because impedance spectroscopy measurements can be performed with low-cost portable instruments, the immunosensor proposed here can be applied in point-of-care diagnostics for mass testing, even in places with limited resources, as an alternative to the common diagnostics methods.

Nanodiamonds and natural deep eutectic solvents as potential carriers for lipase

This study investigates the use of nanodiamonds (ND) as a promising carrier for enzyme immobilization and compares the effectiveness of immobilized and native enzymes. Three different enzyme types were tested, of which Rhizopus niveus lipase (RNL) exhibited the highest relative activity, up to 350 %. Under optimized conditions (1 h, pH 7.0, 40 °C), the immobilized ND-RNL showed a maximum specific activity of 0.765 U mg-1, significantly higher than native RNL (0.505 U mg-1). This study highlights a notable enhancement in immobilized lipase; furthermore, the enzyme can be recycled in the presence of a natural deep eutectic solvent (NADES), retaining 76 % of its initial activity. This aids in preserving the native conformation of the protein throughout the reusability process. A test on brine shrimp revealed that even at low concentrations, ND-RNL had minimal toxicity, indicating its low cytotoxicity. The in silico molecular dynamics simulations performed in this study offer valuable insights into the mechanism of interactions between RNL and ND, demonstrating that RNL immobilization onto NDs enhances its efficiency and stability. All told, these findings highlight the immense potential of ND-immobilized RNL as an excellent candidate for biological applications and showcase the promise of further research in this field.

Uniform trehalose nanogels for glucagon stabilization

Glucagon is a peptide hormone that acts via receptor-mediated signaling predominantly in the liver to raise glucose levels by hepatic glycogen breakdown or conversion of noncarbohydrate, 3 carbon precursors to glucose by gluconeogenesis. Glucagon is administered to reverse severe hypoglycemia, a clinical complication associated with type 1 diabetes. However, due to low stability and solubility at neutral pH, there are limitations in the current formulations of glucagon. Trehalose methacrylate-based nanoparticles were utilized as the stabilizing and solubilizing moiety in the system reported herein. Glucagon was site-selectively modified to contain a cysteine at amino acid number 24 to covalently attach to the methacrylate-based polymer containing pyridyl disulfide side chains. PEG2000 dithiol was employed as the crosslinker to form uniform nanoparticles. Glucagon nanogels were monitored in Dulbecco's phosphate-buffered saline (DPBS) pH 7.4 at various temperatures to determine its long-term stability in solution. Glucagon nanogels were stable up to at least 5 months by size uniformity when stored at -20 °C and 4 °C, up to 5 days at 25 °C, and less than 12 hours at 37 °C. When glucagon stability was studied by either HPLC or thioflavin T assays, the glucagon was intact for at least 5 months at -20 °C and 4 °C within the nanoparticles at -20 °C and 4 °C and up to 2 days at 25 °C. Additionally, the glucagon nanogels were studied for toxicity and efficacy using various assays in vitro. The findings indicate that the nanogels were nontoxic to fibroblast cells and nonhemolytic to red blood cells. The glucagon in the nanogels was as active as glucagon alone. These results demonstrate the utility of trehalose nanogels towards a glucagon formulation with improved stability and solubility in aqueous solutions, particularly useful for storage at cold temperatures.

Phage formulations and delivery strategies: Unleashing the potential against antibiotic-resistant bacteria

Bacterial control promoted by bacteriophages (phages) is an attractive tool in the face of the antibiotic crisis triggered by the exacerbated use of these drugs. Despite the growing interest in using these viruses, some gaps still need answers, such as the protection and delivery of phages. Some limitation points involve the degradation of phage proteins by enzymes or inactivation in low-pH environments. In this review, a literature search using keywords related to the field of virus delivery formulations was done to understand the current scenario of using delivery techniques and phage formulations. A total of 2096 raw results were obtained, which resulted in 140 publications after refinement. These studies were analyzed for main application techniques and areas, keywords, and countries. Of the total, 57% of the publications occurred in the last five years, and the encapsulation technique was the most used among the articles analyzed. As excipient agents, lactose, trehalose, mannitol, PEG, and Leucine stand out. The development of phage formulations, protection approaches, their delivery routes, and the knowledge about the best application strategy enables the use of these organisms in several sectors. It can act as a powerful tool against antibiotic-resistant bacteria.

How spray drying processing and solution composition can affect the mAbs stability in reconstituted solutions for subcutaneous injections. Part II: Exploring each protein stabilizer effect

Despite extensive research in spray drying of biopharmaceuticals, identifying the optimal formulation composition and process conditions to minimize the various stresses a biopharmaceutical undergoes during this drying process. The current study extends previous research on investigating how spray drying processing and solution composition can affect the stability of monoclonal antibodies (mAbs) in reconstituted solutions for subcutaneous injections. The decoupling process stresses on a model mAb (mAb-A) compared to the effect of coupled spray-drying stresses revealed that excipients and protein concentration had a more pronounced effect on stabilizing mAb-A against shear and thermal/dehydration stresses than spray drying operating conditions. These results prompted the continuation of the study, with the aim to investigate in greater depth the effect of mAb-A concentration in the formulation designated to spray-drying and then the effect of type and the concentration of individual excipients (sugars, amino acids and surfactants). The outcomes of this investigation suggest that a general increase in the concentration of excipients, particularly surfactants, correlates with a reduction in aggregation and turbidity observed in the reconstituted spray-dried mAb-A powders. These results, contribute to the identification of a suitable composition for a spray-dried mAb-A powder that ensures robust stability of the protein in reconstituted solutions intended for subcutaneous injection. This valuable insight has important implications for advancing the development of pharmaceutical formulations with enhanced stability and efficacy.

How spray drying processing and solution composition can affect the mAbs stability in reconstituted solutions for subcutaneous injections. Part I: Contribution of processing stresses against composition

Spray drying is increasingly being applied to process biopharmaceuticals, particularly monoclonal antibodies (mAbs). However, due to their protein nature, mAbs are susceptible to degradation when subjected to various stresses during a drying process. Despite extensive research in this domain, identifying the appropriate formulation composition and spray drying conditions remains a complex challenge, requiring further studies to enhance the understanding on how process and formulation parameters impact mAb stability in reconstituted solutions. This research aims to explore spray drying as technique for producing pharmaceutical mAbs-based powders intended for reconstitution and subcutaneous injection. In the initial phase of this study, using a model mAb (mAb-A), the influence of dissociated and coupled process stresses on protein stability after solution reconstitution was investigated. The findings revealed a detrimental interplay of mechanical, interfacial, and thermal/dehydration stresses on mAb-A stability, notably characterized by an increase in protein aggregation. Subsequently, in a second phase, the study delved into the impact of spray drying processing conditions, the level of excipients, and protein concentration on mAb-A aggregation in reconstituted solutions. The obtained results highlighted the critical role of formulation composition as a parameter deserving further study, specifically concerning the selection of type and concentration of stabilizers to be added in the liquid mAb-A solution to be dried.

Combinations of arginine and pullulan reveal the selective effect of stabilization mechanisms on different lyophilized proteins

The stability of lactate dehydrogenase (LDH) and β-galactosidase (β-gal), incorporated in arginine/pullulan (A/P) mixtures at various weight ratios by lyophilization, was determined. The physicochemical characteristics of various A/P mixtures were assessed. With decreasing A/P ratios, the glass transition temperature of the formulations increased. Furthermore, arginine crystallization due to high relative humidity (RH) exposure was prevented at an A/P weight ratio of 4/6 or less. When stored at 0 % RH / 60 °C for 4 weeks, arginine was superior to pullulan as stabilizer. During storage at 43 % RH / 30 ℃ for 4 weeks, the enzymatic activity of LDH was best retained at an A/P weight ratio of 2/8, while β-gal activity was relatively well-retained at A/P weight ratios of both 8/2 and 2/8. LDH seemed to be more prone to degradation in the rubbery state. In the glassy state, β-gal degraded faster than LDH. Solid-state nuclear magnetic resonance spectroscopy showed that (labeled) arginine experienced a different interaction in the two protein samples, reflecting a modulation of long-range correlations of the arginine side chain nitrogen atoms (Nε, Nη). In summary, LDH stabilization in the A/P matrix requires vitrification. Further stabilization difference between LDH and β-gal may be dependent on the interaction with arginine.

Stability Comparison Between Microglassification and Lyophilization Using a Monoclonal Antibody

Producing solid-state formulations of biologics remains a daunting task despite the prevalent use of lyophilization and spray drying technologies in the biopharmaceutical industry. The challenges include protein stability (temperature stresses), high capital costs, particle design/controllability, shortened processing times and manufacturing considerations (scalability, yield improvements, aseptic operation, etc.). Thus, scientists/engineers are constantly working to improve existing methodologies and exploring novel dehydration/powder-forming technologies. Microglassification™ is a dehydration technology that uses solvent extraction to rapidly dehydrate protein formulations at ambient temperatures, eliminating the temperature stress experienced by biologics in traditional lyophilization and spray drying methods. The process results in microparticles that are spherical, dense, and chemically stable. In this study, we compared the molecular stability of a monoclonal antibody formulation processed by lyophilization to the same formulation processed using Microglassification™. Both powders were placed on stability for 3 months at 40 °C and 6 months at 25 °C. Both dehydration methods showed similar chemical stability, including percent monomer, charge variants, and antigen binding. These results show that Microglassification™ is viable for the production of stable solid-state monoclonal antibody formulations.

Advances in protein-based microcapsules and their applications: A review

Due to their excellent emulsification, biocompatibility, and biological activity, proteins are widely used as microcapsule wall materials for encapsulating drugs, natural bioactive substances, essential oils, probiotics, etc. In this review, we summarize the protein-based microcapsules, discussing the types of proteins utilized in microcapsule wall materials, the preparation process, and the main factors that influence their properties. Additionally, we conclude with examples of the vital role of protein-based microcapsules in advancing the food industry from primary processing to deep processing and their potential applications in the biomedical, chemical, and textile industries. However, the low stability and controllability of protein wall materials lead to degraded performance and quality of microcapsules. Protein complexes with polysaccharides or modifications to proteins are often used to improve the thermal instability, pH sensitivity, encapsulation efficiency and antioxidant capacity of microcapsules. In addition, factors such as wall material composition, wall material ratio, the ratio of core to wall material, pH, and preparation method all play critical roles in the preparation and performance of microcapsules. The application area and scope of protein-based microcapsules can be further expanded by optimizing the preparation process and studying the microcapsule release mechanism and control strategy.

Lyophilization for bacteria preservation: a promising approach for Yersinia pestis strains from an unique collection in Brazil (Fiocruz-CYP)

Yersinia pestis, the causative agent of plague, is a highly virulent bacterium that poses a significant threat to human health. Preserving this bacterium in a viable state is crucial for research and diagnostic purposes. This paper presents and evaluates a simple lyophilization protocol for the long-term storage of Y. pestis strains from Fiocruz-CYP, aiming to explore its impact on viability and long-term stability, while replacing the currently used methodologies. The lyophilization tests were conducted using the non-virulent Y. pestis strain EV76, subjected to the lyophilization process under vacuum conditions. Viability assessment was performed to evaluate the effects of lyophilization and storage conditions on Y. pestis under multiple temperature conditions (- 80 °C, - 20 °C, 4-8 °C and room temperature). The lyophilization protocol employed in this study consistently demonstrated its efficacy in maintaining high viability rates for Y. pestis samples in a up to one year follow-up. The storage temperature that consistently exhibited the highest recovery rates was - 80 °C, followed by - 20 °C and 4-8 °C. Microscopic analysis of the post-lyophilized cultures revealed preserved morphological features, consistent with viable bacteria. The high viability rates observed in the preserved samples indicate the successful preservation of Y. pestis using this protocol. Overall, the presented lyophilization protocol provides a valuable tool for the long-term storage of Y. pestis, offering stability, viability, and functionality. By refining the currently used methods of lyophilization, this protocol can improve long-term preservation for Y. pestis strains collections, facilitating research efforts, diagnostic procedures, and the development of preventive and therapeutic strategies against plague.

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.

PHB production by Bacillus megaterium strain MNSH1-9K-1 using low-cost media

Plastics are widely used for diverse applications due to their versatility. However, their negative impact on ecosystems is undeniable due to their long-term degradation. Thus, there is a rising need for developing eco-friendlier alternatives to substitute fossil-based plastics, like biopolymers. PHA are synthesized intracellularly by microorganisms under stressful conditions of growth and have similar characteristics to conventional polymers, like their melting point, transition temperatures, crystallinity, and flexibility. Although it is feasible to use biopolymers for diverse industrial applications, their elevated production cost due to the supplies needed for microbiological procedures and the low productivity yields obtained have been the main limiting factors for their commercial success. The present study assessed the ability of Bacillus megaterium strain MNSH1-9K-1 to produce biopolymers using low-cost media from different kinds of fruit-peel residues. The results show that MNSH1-9K-1 can produce up to 58 g/L of PHB when grown in a medium prepared from orange-peel residues. The data obtained provide information to enhance the scalability of these kinds of biotechnological processes.

Lyoprotectant Constituents Suited for Lyophilization and Reconstitution of Stem-Cell-Derived Extracellular Vesicles

Stem-cell-derived extracellular vesicles (EVs) are emerging as an alternative approach to stem cell therapy. Successful lyophilization of EVs could enable convenient storage and distribution of EV medicinal products at room temperature for long periods, thus considerably increasing the accessibility of EV therapeutics to patients. In this study, we aimed to identify an appropriate lyoprotectant composition for the lyophilization and reconstitution of stem-cell-derived EVs. MSC-derived EVs were lyophilized using different lyoprotectants, such as dimethyl sulfoxide, mannitol, trehalose, and sucrose, at varying concentrations. Our results revealed that a mixture of trehalose and sucrose at high concentrations could support the formation of amorphous ice by enriching the amorphous phase of the solution, which successfully inhibited the acceleration of buffer component crystallization during lyophilization. Lyophilized and reconstituted EVs were thoroughly evaluated for concentration and size, morphology, and protein and RNA content. The therapeutic effects of the reconstituted EVs were examined using a tube formation assay with human umbilical vein endothelial cells. After rehydration of the lyophilized EVs, most of their generic characteristics were well-maintained, and their therapeutic capacity recovered to levels similar to those of freshly collected EVs. The concentrations and morphologies of the lyophilized EVs were similar to the initial features of the fresh EV group until day 30 at room temperature, although their therapeutic capacity appeared to decrease after 7 days. Our study suggests an appropriate composition of lyoprotectants, particularly for EV lyophilization, which could encourage the applications of stem-cell-derived EV therapeutics in the health industry.

VARPA: In Silico Additive Screening for Protein-Based Lighting Devices

Protein optoelectronics is an emerging field facing implementation and stabilization challenges of proteins in harsh non-natural environments, such as dry polymers, inorganic materials, etc., operating at high temperatures/irradiations. In this context, additives promoting structural and functional protein stabilization are paramount to realize highly performing devices. On one hand, trial-error experimental assays based on previous knowledge of classical additives in aqueous solutions are effort/time-consuming, while their translation to water-less matrices is uncertain. On the other hand, computational simulations (molecular dynamics, electronic structure methods, etc.) are limited by the system size and time. Herein, ligand-binding affinity and atomic perturbations to create a day-fast computational method combining Vina And Rosetta for Protein Additives (VARPA) to simulate the stabilization effect of sugars for the archetypal enhanced green fluorescent protein embedded in a standard dry polymer color-converting filter for bio-hybrid light-emitting diodes is merged. The VARPA's sugar additive prediction trend for protein stabilization is nicely validated by thermal and photophysical studies as well as lighting device analysis. The device stability followed the predicted enhanced stability trend, reaching a 40-fold improvement compared to reference devices. Overall, VARPA can be adapted to a myriad of additives and proteins, driving first-step experimental efforts toward highly performing protein devices.

Understanding the impact of mannitol on physical stability and aerosolization of spray-dried protein powders for inhalation

Pulmonary delivery of protein-based therapeutics, including antibodies, is a promising option for treating respiratory diseases. Spray drying is a widely used method for producing dry powder formulations with mannitol being a commonly used excipient for these inhalation formulations. There is limited research available concerning the utilization of mannitol as an excipient in the spray drying of proteins and its impact on aerosol performance. This study highlights the importance to understand mannitol's potential role and impact in this context. To investigate the impact of mannitol on physical stability and aerosolization of spray-dried protein formulations, bovine serum albumin (BSA) was employed as a model protein and formulated with different concentrations of mannitol via spray drying. The spray-dried solids were characterized for their particle size using Malvern mastersizer and aerodynamic particle size using next generation impactor (NGI). Additionally, the solids were characterized with solid-state Fourier-transform infrared spectroscopy (ssFTIR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and solid-state nuclear magnetic resonance spectroscopy (ssNMR) to analyze the change in their secondary structure, crystallinity, particle morphology, and protein-excipient interaction, respectively. Size exclusion chromatography (SEC) was used to investigate changes in monomer content resulting from storage under stressed condition of 40 °C. Protein formulations containing more than 33 % mannitol by weight showed crystallization tendencies, causing an increase in monomer loss over time. ssNMR data also showed mixing heterogeneity of BSA and mannitol in the formulations with high mannitol contents. Futhermore, fine particle fraction (FPF) was found to decrease over time for the formulations containing BSA: Mannitol in the ratios of 2:1, 1:2, and 1:5, due to particle agglomeration induced by crystallization of mannitol. This study underscores the significant influence of excipients such as mannitol on the aerosol performance and storage stability of spray-dried protein formulations.

Long-acting inhaled medicines: Present and future

Inhaled medicines continue to be an essential part of treatment for respiratory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. In addition, inhalation technology, which is an active area of research and innovation to deliver medications via the lung to the bloodstream, offers potential advantages such as rapid onset of action, enhanced bioavailability, and reduced side effects for local treatments. Certain inhaled macromolecules and particles can also end up in different organs via lymphatic transport from the respiratory epithelium. While the majority of research on inhaled medicines is focused on the delivery technology, particle engineering, combination therapies, innovations in inhaler devices, and digital health technologies, researchers are also exploring new pharmaceutical technologies and strategies to prolong the duration of action of inhaled drugs. This is because, in contrast to most inhaled medicines that exert a rapid onset and short duration of action, long-acting inhaled medicines (LAIM) improve not only the patient compliance by reducing the dosing frequency, but also the effectiveness and convenience of inhaled therapies to better manage patients' conditions. This paper reviews the advances in LAIM, the pharmaceutical technologies and strategies for developing LAIM, and emerging new inhaled modalities that possess a long-acting nature and potential in the treatment and prevention of various diseases. The challenges in the development of the future LAIM are also discussed where active research and innovations are taking place.

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.

Freeze-Drying of Encapsulated Bacteriophage T4 to Obtain Shelf-Stable Dry Preparations for Oral Application

Therapeutic application of bacterial viruses (phage therapy) has in recent years been rediscovered by many scientists, as a method which may potentially replace conventional antibacterial strategies. However, one of the main problems related to phage application is the stability of bacterial viruses. Though many techniques have been used to sustain phage activity, novel tools are needed to allow long-term phage storage and application in versatile forms. In this study, we combined two well-known methods for bacteriophage immobilization. First, encapsulated phages were obtained by means of extrusion-ionic gelation, and then alginate microspheres were dried using the lyophilization process (freeze-drying). To overcome the risk of phage instability upon dehydration, the microspheres were prepared with the addition of 0.3 M mannitol. Bacteriophage-loaded microspheres were stored at room temperature for 30 days and subsequently exposed to simulated gastric fluid (SGF). The survival of encapsulated phages after drying was significantly higher in the presence of mannitol. The highest number of viable bacteriophages exceeding 4.8 log10 pfu/mL in SGF were recovered from encapsulated and freeze-dried microspheres, while phages in lyophilized lysate were completely inactivated. Although the method requires optimization, it may be a promising approach for the immobilization of bacteriophages in terms of practical application.

Stability of Naked Nucleic Acids under Physical Treatment and Powder Formation: Suitability for Development as Dry Powder Formulations for Inhalation

A number of functional nucleic acids, including plasmid DNA (pDNA) and small interfering RNA (siRNA), have been attracting increasing attention as new therapeutic modalities worldwide. Dry pDNA and siRNA powder formulations for inhalation are considered practical in clinical applications for respiratory diseases. However, physical stresses in the powder-forming process may destabilize nucleic acids, particularly when vectors with stabilizing effects are not used. We herein compare the stability of naked pDNA and siRNA through various physical treatments and two powder-forming processes. The structural and functional integrities of pDNA were markedly reduced via sonication, heating, and atomization, whereas those of siRNA were preserved throughout all of the physical treatments investigated. Spray-dried and spray-freeze-dried powders of siRNA maintained their structural and functional integrities, whereas those of pDNA did not. These results demonstrate that siRNA is more suitable for powder formation in the naked state than pDNA due to its higher stability under physical treatments. Furthermore, a spray-freeze-dried powder with a high content of naked siRNA (12% of the powder) was successfully produced that preserved its structural and functional integrities, achieving high aerosol performance with a fine particle fraction of approximately 40%.

Stabilization challenges and aggregation in protein-based therapeutics in the pharmaceutical industry

Protein-based therapeutics have revolutionized the pharmaceutical industry and become vital components in the development of future therapeutics. They offer several advantages over traditional small molecule drugs, including high affinity, potency and specificity, while demonstrating low toxicity and minimal adverse effects. However, the development and manufacturing processes of protein-based therapeutics presents challenges related to protein folding, purification, stability and immunogenicity that should be addressed. These proteins, like other biological molecules, are prone to chemical and physical instabilities. The stability of protein-based drugs throughout the entire manufacturing, storage and delivery process is essential. The occurrence of structural instability resulting from misfolding, unfolding, and modifications, as well as aggregation, poses a significant risk to the efficacy of these drugs, overshadowing their promising attributes. Gaining insight into structural alterations caused by aggregation and their impact on immunogenicity is vital for the advancement and refinement of protein therapeutics. Hence, in this review, we have discussed some features of protein aggregation during production, formulation and storage as well as stabilization strategies in protein engineering and computational methods to prevent aggregation.

Solidification and oral delivery of biologics to the colon- A review

The oral delivery of biologics such as therapeutic proteins, peptides and oligonucleotides for the treatment of colon related diseases has been the focus of increasing attention over the last years. However, the major disadvantage of these macromolecules is their degradation propensity in liquid state which can lead to the undesirable and complete loss of function. Therefore, to increase the stability of the biologic and reduce their degradation propensity, formulation techniques such as solidification can be performed to obtain a stable solid dosage form for oral administration. Due to their fragility, stress exerted on the biologic during solidification has to be reduced with the incorporation of stabilizing excipients into the formulation. This review focuses on the state-of-the-art solidification techniques required to obtain a solid dosage form for the oral delivery of biologics to the colon and the use of suitable excipients for adequate stabilization upon solidification. The solidifying processes discussed within this review are spray drying, freeze drying, bead coating and also other techniques such as spray freeze drying, electro spraying, vacuum- and supercritical fluid drying. Further, the colon as site of absorption in both healthy and diseased state is critically reviewed and possible oral delivery systems for biologics are discussed.

Phage therapy: a revolutionary shift in the management of bacterial infections, pioneering new horizons in clinical practice, and reimagining the arsenal against microbial pathogens

The recent approval of experimental phage therapies by the FDA and other regulatory bodies with expanded access in cases in the United States and other nations caught the attention of the media and the general public, generating enthusiasm for phage therapy. It started to alter the situation so that more medical professionals are willing to use phage therapies with conventional antibiotics. However, more study is required to fully comprehend phage therapy's potential advantages and restrictions, which is still a relatively new field in medicine. It shows promise, nevertheless, as a secure and prosperous substitute for antibiotics when treating bacterial illnesses in animals and humans. Because of their uniqueness, phage disinfection is excellent for ready-to-eat (RTE) foods like milk, vegetables, and meat products. The traditional farm-to-fork method can be used throughout the food chain to employ bacteriophages to prevent food infections at all production stages. Phage therapy improves clinical outcomes in animal models and lowers bacterial burdens in numerous preclinical investigations. The potential of phage resistance and the need to make sure that enough phages are delivered to the infection site are obstacles to employing phages in vivo. However, according to preclinical studies, phages appear to be a promising alternative to antibiotics for treating bacterial infections in vivo. Phage therapy used with compassion (a profound understanding of and empathy for another's suffering) has recently grown with many case reports of supposedly treated patients and clinical trials. This review summarizes the knowledge on the uses of phages in various fields, such as the food industry, preclinical research, and clinical settings. It also includes a list of FDA-approved bacteriophage-based products, commercial phage products, and a global list of companies that use phages for therapeutic purposes.

Use of Trehalose as an Additive to Bacteriophage Vb_Pd_PDCC-1: Long-Term Preservation Analysis and Its Biocontrol Against Vibrio diabolicus Infection

Phage therapy is a promising alternative to control bacterial diseases and the increasing problem of antibiotic resistance. In this sense, this research evaluates the viability of lyophilized vibrio phage vB_Pd_PDCC-1 using trehalose as a preservative excipient at different concentrations (4, 2, 1, and 0.5% w/v) and its potential for phage therapy application against a pathogenic bacteria Vibrio diabolicus in brine shrimp nauplii (Artemia franciscana). The lyophilized phages were stored at 4 and 23 °C and rehydrated using biological sterile saline solution to test their viability at days 1, 15, and 60 post-lyophilization. The results showed that trehalose is beneficial in maintaining the viability of post-lyophilization phages (without titer losses) at 4 °C and even at room temperature (23 °C). When lyophilized phages with 4% w/v trehalose concentration were stored at 23 °C, they had not titer losses among the trials; viability and titer concentration were maintained up to 60 days at log 7. The use of lyophilized phage PDCC-1 increased brine shrimp survival and reduced Vibrio concentrations. The present study has identified trehalose as a promising lyophilization excipient to effectively preserve lyophilized bacteriophages for biotechnological applications and long-term storage.

From cell factories to patients: Stability challenges in biopharmaceuticals manufacturing and administration with mitigation strategies

Active ingredients of biopharmaceuticals consist of a wide array of biomolecular structures, including those of enzymes, monoclonal antibodies, nucleic acids, and recombinant proteins. Recently, these molecules have dominated the pharmaceutical industry owing to their safety and efficacy. However, their manufacturing is hindered by high cost, inadequate batch-to-batch equivalence, inherent instability, and other quality issues. This article is an up-to-date review of the challenges encountered during different stages of biopharmaceutical production and mitigation of problems arising during their development, formulation, manufacturing, and administration. It is a broad overview discussion of stability issues encountered during product life cycle i.e., upstream processing (aggregation, solubility, host cell proteins, color change), downstream bioprocessing (aggregation, fragmentation), formulation, manufacturing, and delivery to patients.

Enhanced powder dispersion of dual-excipient spray-dried powder formulations of a monoclonal antibody and its fragment for local treatment of severe asthma

The advent of biologics has brought renewed hope for patients with severe asthma, a condition notorious for being hampered by poor response to conventional therapies and adverse drug reactions owing to corticosteroid dependence. However, biologics are administered as injections, thereby precluding the benefits inhalation therapy could offer such as increased bioavailability at the site of action, minimal systemic side effects, non-invasiveness, and self-administration. Here, 2-hydroxypropyl-beta-cyclodextrin and ʟ-leucine were co-spray-dried, as protein stabiliser and dispersion enhancer, respectively, at various weight ratios to produce a series of formulation platforms. Powder aerosolisation characteristics and particle morphology were assessed for suitability for pulmonary delivery. The selected platform with the best aerosol performance, a 1:1 ratio of the excipients, was then incorporated with a monoclonal antibody directed against IL-4 receptor alpha or its antigen-binding fragment. The dual-excipient antibody formulations exhibited emitted fraction of at least 80% and fine particle fraction exceeding 60% in cascade impactor study, while the residual moisture content was within a desirable range between 1% and 3%. The in vitro antigen-binding ability and inhibitory potency of the spray-dried antibody were satisfactorily preserved. The results from this study corroborate the viability of inhaled solid-state biomacromolecules as a promising treatment approach for asthma.

Bio-Inspired Nanomaterials for Micro/Nanodevices: A New Era in Biomedical Applications

Exploring bio-inspired nanomaterials (BINMs) and incorporating them into micro/nanodevices represent a significant development in biomedical applications. Nanomaterials, engineered to imitate biological structures and processes, exhibit distinctive attributes such as exceptional biocompatibility, multifunctionality, and unparalleled versatility. The utilization of BINMs demonstrates significant potential in diverse domains of biomedical micro/nanodevices, encompassing biosensors, targeted drug delivery systems, and advanced tissue engineering constructs. This article thoroughly examines the development and distinctive attributes of various BINMs, including those originating from proteins, DNA, and biomimetic polymers. Significant attention is directed toward incorporating these entities into micro/nanodevices and the subsequent biomedical ramifications that arise. This review explores biomimicry's structure-function correlations. Synthesis mosaics include bioprocesses, biomolecules, and natural structures. These nanomaterials' interfaces use biomimetic functionalization and geometric adaptations, transforming drug delivery, nanobiosensing, bio-inspired organ-on-chip systems, cancer-on-chip models, wound healing dressing mats, and antimicrobial surfaces. It provides an in-depth analysis of the existing challenges and proposes prospective strategies to improve the efficiency, performance, and reliability of these devices. Furthermore, this study offers a forward-thinking viewpoint highlighting potential avenues for future exploration and advancement. The objective is to effectively utilize and maximize the application of BINMs in the progression of biomedical micro/nanodevices, thereby propelling this rapidly developing field toward its promising future.

Development of Solid-State Storage for Cell-Free Expression Systems

The fragility of biological systems during storage, transport, and utilization necessitates reliable cold-chain infrastructure and limits the potential of biotechnological applications. In order to unlock the broad applications of existing and emerging biological technologies, we report the development of a novel solid-state storage platform for complex biologics. The resulting solid-state biologics (SSB) platform meets four key requirements: facile rehydration of solid materials, activation of biochemical activity, ability to support complex downstream applications and functionalities, and compatibility for deployment in a variety of reaction formats and environments. As a model system of biochemical complexity, we utilized crudeEscherichia colicell extracts that retain active cellular metabolism and support robust levels of in vitro transcription and translation. We demonstrate broad versatility and utility of SSB through proof-of-concepts for on-demand in vitro biomanufacturing of proteins at a milliliter scale, the activation of downstream CRISPR activity, as well as deployment on paper-based devices. SSBs unlock a breadth of applications in biomanufacturing, discovery, diagnostics, and education in resource-limited environments on Earth and in space.

Listeria monocytogenes in food businesses: From persistence strategies to intervention/prevention strategies-A review

In 2023, Listeria monocytogenes persistence remains a problem in the food business. A profound understanding of how this pathogen persists may lead to better aimed intervention/prevention strategies. The lack of a uniform definition of persistence makes the comparison between studies complex. Harborage sites offer protection against adverse environmental conditions and form the ideal habitat for the formation of biofilms, one of the major persistence strategies. A retarded growth rate, disinfectant resistance/tolerance, desiccation resistance/tolerance, and protozoan protection complete the list of persistence strategies for Listeria monocytogenes and can occur on themselves or in combination with biofilms. Based on the discussed persistence strategies, intervention strategies are proposed. By enhancing the focus on four precaution principles (cleaning and disinfection, infrastructure/hygienic design, technical maintenance, and work methodology) as mentioned in Regulation (EC) No. 852/2004, the risk of persistence can be decreased. All of the intervention strategies result in obtaining and maintaining a good general hygiene status throughout the establishment at all levels ranging from separate equipment to the entire building.

Spectroscopic analysis of recombinant human growth hormone in the presence of sucrose and trehalose

Recombinant human growth hormone (rhGH) is a therapeutic protein, associated with various human diseases, such as growth hormone deficiency. One of the interesting issues in the formulation of therapeutic proteins is excipients like disaccharides. In the current study, we try to compare the effect of sucrose and trehalose on the structure of rhGH in the liquid state at 25°C and 55°C. We use spectroscopic techniques including intrinsic and extrinsic fluorescence, Fourier-transform infrared (FTIR), circular dichroism (CD), dynamic light scattering (DLS), and time-resolved fluorescence. FTIR shows a slight change in the secondary structure of rhGH in presence of the sugars as sucrose is more effective than trehalose. Fluorescence investigations also confirm the enhancements of folding of rhGH and fluorescein isothiocyanate (FITC)-rhGH in presence of sucrose (1.5-fold more than trehalose). Also, we studied sucrose's effect on the rete of aggregation of rhGH using spectroscopy of Congo red, and fluorescence imaging of thioflavin T (ThT)-treated samples. It can be suggested that sucrose facilitates the amyloid formation of rhGH during 20 days of incubation at 37°C. This study will help to understand the growth hormone structural behavior in the liquid state in the presence of sucrose and trehalose in vitro.

Stability of Monoclonal Antibodies as Solid Formulation for Auto-Injectors: A Pilot Study

Drug adherence is a significant medical issue, often responsible for sub-optimal outcomes during the treatment of chronic diseases such as rheumatoid or psoriatic arthritis. Monoclonal antibodies (which are exclusively given parenterally) have been proven to be an effective treatment in these cases. The use of auto-injectors is an effective strategy to improve drug adherence in parenteral treatments since these pen-like devices offer less discomfort and increased user-friendliness over conventional syringe-based delivery. This study aims to investigate the feasibility of including a monoclonal antibody as a solid formulation inside an auto-injector pen. Specifically, the objective was to evaluate the drug stability after a concentration (to reduce the amount of solvent and space needed) and freeze-drying procedure. A preliminary screening of excipients to improve stability was also performed. The nano-DSC results showed that mannitol improved the stability of the concentrated, freeze-dried antibody in comparison to its counterpart without it. However, a small instability of the CH2 domain was still found for mannitol samples, which will warrant further investigation. The present results serve as a stepping stone towards advancing future drug delivery systems that will ultimately improve the patient experience and associated drug adherence.

Placental-Derived Biomaterials and Their Application to Wound Healing: A Review

Chronic wounds are associated with considerable patient morbidity and present a significant economic burden to the healthcare system. Often, chronic wounds are in a state of persistent inflammation and unable to progress to the next phase of wound healing. Placental-derived biomaterials are recognized for their biocompatibility, biodegradability, angiogenic, anti-inflammatory, antimicrobial, antifibrotic, immunomodulatory, and immune privileged properties. As such, placental-derived biomaterials have been used in wound management for more than a century. Placental-derived scaffolds are composed of extracellular matrix (ECM) that can mimic the native tissue, creating a reparative environment to promote ECM remodeling, cell migration, proliferation, and differentiation. Reliable evidence exists throughout the literature to support the safety and effectiveness of placental-derived biomaterials in wound healing. However, differences in source (i.e., anatomical regions of the placenta), preservation techniques, decellularization status, design, and clinical application have not been fully evaluated. This review provides an overview of wound healing and placental-derived biomaterials, summarizes the clinical results of placental-derived scaffolds in wound healing, and suggests directions for future work.

Effect of Buffer Salts on Physical Stability of Lyophilized and Spray-Dried Protein Formulations Containing Bovine Serum Albumin and Trehalose

This study examined the effect of buffer salts on the physical stability of spray-dried and lyophilized formulations of a model protein, bovine serum albumin (BSA). BSA formulations with various buffers were dried by either lyophilization or spray drying. The protein powders were then characterized using solid-state Fourier transform infrared spectroscopy (ssFTIR), powder X-ray diffraction (PXRD), size exclusion chromatography (SEC), solid-state hydrogen/deuterium exchange with mass spectrometry (ssHDX-MS), and solid-state nuclear magnetic resonance spectroscopy (ssNMR). Particle characterizations such as Brunauer-Emmett-Teller (BET) surface area, particle size distribution, and particle morphology were also performed. Results from conventional techniques such as ssFTIR did not exhibit correlations with the physical stability of studied formulations. Deconvoluted peak areas of deuterated samples from the ssHDX-MS study showed a satisfactory correlation with the loss of the monomeric peak area measured by SEC (R2 of 0.8722 for spray-dried formulations and 0.8428 for lyophilized formulations) in the 90-day accelerated stability study conducted at 40°C. mDSC and PXRD was unable to measure phase separation in the samples right after drying. In contrast, ssNMR successfully detected the occurrence of phase separation between the succinic buffer component and protein in the lyophilized formulation, which results in a distribution of microenvironmental acidity and the subsequent loss of long-term stability. Moreover, our results suggested that buffer salts have less impact on physical stability for the spray-dried formulations than the lyophilized solids.

Impact of Controlled Ice Nucleation and Lyoprotectants on Nanoparticle Stability during Freeze-drying and upon Storage

The freezing step of the lyophilization process can impact nanoparticle stability due to increased particle concentration in the freeze-concentrate. Controlled ice nucleation is a technique to achieve uniform ice crystal formation between vials in the same batch and has attracted increasing attention in pharmaceutical industry. We investigated the impact of controlled ice nucleation on three types of nanoparticles: solid lipid nanoparticles (SLNs), polymeric nanoparticles (PNs), and liposomes. Freezing conditions with different ice nucleation temperatures or freezing rates were employed for freeze-drying all formulations. Both in-process stability and storage stability up to 6 months of all formulations were assessed. Compared with spontaneous ice nucleation, controlled ice nucleation did not cause significant differences in residual moisture and particle size of freeze-dried nanoparticles. The residence time in the freeze-concentrate was a more critical factor influencing the stability of nanoparticles than the ice nucleation temperature. Liposomes freeze-dried with sucrose showed particle size increase during storage regardless of freezing conditions. By replacing sucrose with trehalose, or adding trehalose as a second lyoprotectant, both the physical and chemical stability of freeze-dried liposomes improved. Trehalose was a preferable lyoprotectant than sucrose to better maintain the long-term stability of freeze-dried nanoparticles at room temperature or 40°C.

Impact of ZIF-8, ArgHCl, and Ionic Liquid-Based Formulations on the Conformational and Colloidal Stability of Antibodies

Various formulations consisting of biomaterials zirconium imidazolate framework-8 (ZIF-8), choline acetate ([Ch][Ac]), and arginine hydrochloride (argHCl) are optimized to study the stability of antibody, Immunoglobulin G (IgG). We have performed several instrumentations including UV-visible spectroscopy, dynamic light scattering (DLS), circular dichroism (far UV CD), and atomic force microscopy (AFM) in the presence of all the formulations to investigate the conformational and colloidal stability of the antibodies. Alongside, the packing efficiency of all the formulations was also explored by storing IgG at 4 °C for 3 months. We have tried to investigate the interactions between biomaterials and antibodies with the motive of designing aggregation-resistant formulations. The overall stability of IgG was improved in the presence of [Ch][Ac]; however, ZIF-8 and argHCl cause relatively more aggregation, although the structure was retained in all the formulations. The key aspect of this study is that the presence of [Ch][Ac] increases ZIF-8@IgG's thermal stability and resistance to IgG-argHCl aggregation. All over, for the first time, with different experimental approaches, the impact of each biomaterial individually and in combination is explored to study their effect on the stability of antibodies. Thus, better efficient formulations can be designed for the storage/packaging of IgG-based drugs which ultimately will have more applicability in pharmaceuticals.

Internal microstructure of spray dried particles affects viral vector activity in dry vaccines

To maintain the activity of sensitive biologics during encapsulation by spray drying, a better understanding of deactivation pathways in dried particles is necessary. The effect of solid-air interfaces within dried particles on viral deactivation was examined with three binary excipient blends, mannitol/dextran (MD), xylitol/dextran (XD), and lactose/trehalose (LT). Particles encapsulating human serotype 5 adenovirus viral vector (AdHu5) were produced via both spray drying and acoustic levitation. The particles' internal microstructure was directly visualized, and the location of a viral vector analogue was spatially mapped within the particles by volume imaging using focused ion beam sectioning and scanning electron microscopy. The majority of the viral vector analogue was found at, or near, the solid-air interfaces. Peclet number and crystallization kinetics governed the internal microstructure of the particles: XD particles with minimal internal voids retained the highest viral activity, followed by MD particles with a few large voids, and finally LT particles with numerous internal voids exhibited the lowest viral activity. Overall, AdHu5 activity decreased as the total solid-air interfacial area increased (as quantified by nitrogen sorption). Along with processing losses, this work highlights the importance of surface area within particles as an indicator of activity losses for dried biologics.

Inactivation and aggregation of R-specific 1-(4-hydroxyphenyl)-ethanol dehydrogenase from Aromatoleum aromaticum

R-specific 1-(4-hydroxyphenyl)-ethanol dehydrogenase (R-HPED) is a promising biotool for stereoselective synthesis of chiral aromatic alcohols. This work focused on the evaluation of its stability under storage and in-process conditions in the pH range from 5.5 to 8.5. The relationship between the dynamics of aggregation and activity loss under various pH conditions and in the presence of glucose, serving as a stabilizer, was analysed using spectrophotometric techniques and dynamic light scattering. pH 8.5 was indicated as a representative environment in which the enzyme, despite relatively low activity, shows high stability and the highest total product yield. Based on a series of inactivation experiments, the mechanism of thermal inactivation at pH 8.5 was modelled. The irreversible first-order mechanism of R-HPED inactivation in the temperature range of 47.5-60 °C was verified by isothermal and multi-temperature evaluation of data, confirming that in the alkaline pH 8.5, R-HPED aggregation is the secondary process occurring at already inactivated protein molecules. The rate constants were from 0.029 min^-1 to 0.380 min^-1 for a buffer solution but they decreased to 0.011 min^-1 and 0.161 min^-1, respectively, when 1.5 M glucose was added as a stabilizer. The activation energy was however about 200 kJ mol^-1 in both cases.

The Effect of Erythritol on the Physicochemical Properties of Reformulated, High-Protein, and Sugar-Free Macarons Produced from Whey Protein Isolate Intended for Diabetics, Athletes, and Physically Active People

This study reports the possibility of obtaining sugar-free WPI-based macarons with erythritol addition. The whey protein isolate (WPI) solution (20%, w/v) was whipped, and erythritol was added to the foam at concentrations of 20, 40, and 60 g, with 125 g of almond flour. The rheological properties (τ, G', G″, and tan (δ)) and stability of the macaron batters before baking were evaluated. In order to produce the macarons, the batters were solidified at 147 °C for 12 min. The textural and surface properties (roughness and color), as well as the microstructures and water activities, were determined for the macarons. It was feasible to produce macarons over the entire range of the tested erythritol content. Even the smallest amount of erythritol (20 g) facilitated the preservation of the macaron structure. The medium erythritol concentration (40 g) improved the stability of the batters and their rheology and was the most effective for air pocket stabilization during baking; however, its largest addition (60 g) resulted in an increase in the final macaron volume. The increased erythritol addition improved mechanical properties and shelf life, producing a smoothing effect on the macaron surfaces and having a significant effect on their color co-ordinates.

LB, Endo H, Itaka K, Tachibana K. Efficient mRNA Delivery with Lyophilized Human Serum Albumin-Based Nanobubbles

In this study, we developed an efficient mRNA delivery vehicle by optimizing a lyophilization method for preserving human serum albumin-based nanobubbles (HSA-NBs), bypassing the need for artificial stabilizers. The morphology of the lyophilized material was verified using scanning electron microscopy, and the concentration, size, and mass of regenerated HSA-NBs were verified using flow cytometry, nanoparticle tracking analysis, and resonance mass measurements, and compared to those before lyophilization. The study also evaluated the response of HSA-NBs to 1 MHz ultrasound irradiation and their ultrasound (US) contrast effect. The functionality of the regenerated HSA-NBs was confirmed by an increased expression of intracellularly transferred Gluc mRNA, with increasing intensity of US irradiation. The results indicated that HSA-NBs retained their structural and functional integrity markedly, post-lyophilization. These findings support the potential of lyophilized HSA-NBs, as efficient imaging, and drug delivery systems for various medical applications.

Impact of Different Saccharides on the In-Process Stability of a Protein Drug During Evaporative Drying: From Sessile Droplet Drying to Lab-Scale Spray Drying

OBJECTIVES

Solid biopharmaceutical products can circumvent lower temperature storage and transport and increase remote access with lower carbon emissions and energy consumption. Saccharides are known stabilizers in a solid protein produced via lyophilization and spray drying (SD). Thus, it is essential to understand the interactions between saccharides and proteins and the stabilization mechanism.

METHODS

A miniaturized single droplet drying (MD) method was developed to understand how different saccharides stabilize proteins during drying. We applied our MD to different aqueous saccharide-protein systems and transferred our findings to SD.

RESULTS

The poly- and oligosaccharides tend to destabilize the protein during drying. The oligosaccharide, Hydroxypropyl β-cyclodextrin (HPβCD) shows high aggregation at a high saccharide-to-protein molar ratio (S/P ratio) during MD, and the finding is supported by nanoDSF results. The polysaccharide, Dextran (DEX) leads to larger particles, whereas HPBCD leads to smaller particles. Furthermore, DEX is not able to stabilize the protein at higher S/P ratios either. In contrast, the disaccharide Trehalose Dihydrate (TD) does not increase or induce protein aggregation during the drying of the formulation. It can preserve the protein's secondary structure during drying, already at low concentrations.

CONCLUSION

During the drying of S/P formulations containing the saccharides TD and DEX, the MD approach could anticipate the in-process (in) stability of protein X at laboratory-scale SD. In contrast, for the systems with HPβCD, the results obtained by SD were contradictory to MD. This underlines that depending on the drying operation, careful consideration needs to be applied to the selection of saccharides and their ratios.

How Sugars Protect Dry Protein Structure

Extremotolerant organisms and industry exploit sugars as desiccation protectants, with trehalose being widely used by both. How sugars, in general, and the hydrolytically stable sugar trehalose, in particular, protect proteins is poorly understood, which hinders the rational design of new excipients and implementation of novel formulations for preserving lifesaving protein drugs and industrial enzymes. We employed liquid-observed vapor exchange nuclear magnetic resonance (LOVE NMR), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA) to show how trehalose and other sugars protect two model proteins: the B1 domain of streptococcal protein G (GB1) and truncated barley chymotrypsin inhibitor 2 (CI2). Residues with intramolecular H-bonds are most protected. The LOVE NMR and DSC data indicate that vitrification may be protective. Combining LOVE NMR and TGA data shows that water retention is not important. Our data suggest that sugars protect protein structure as they dry by strengthening intraprotein H-bonds and water replacement and that trehalose is the stress-tolerance sugar of choice because of its covalent stability.

Whey protein hydrolysates as prebiotic and protective agent regulate growth and survival of Lactobacillus rhamnosus CICC22152 during spray/freeze-drying, storage and gastrointestinal digestion

BACKGROUND

Probiotic products are receiving increasing attention because of their tremendous beneficial health effects. However, it is still a great challenge to preserve probiotic viability during processing, storage and gastrointestinal digestion. Encapsulation is a widely known technology for enhancing bacterial viability and product stability. Hence highly hydrolyzed whey protein hydrolysate (HWPH) and moderately hydrolyzed whey protein hydrolysate (MWPH) used as a one-step culture medium and wall material for Lactobacillus rhamnosus were investigated.

RESULTS

H/MWPH-substitutive medium for the growth of Lactobacillus rhamnosus presented double the biomass production compared to other media. The H/MWPH-substitutive medium in combination with freeze drying also led to the highest survival ratio (97.13 ± 9.16%) and cell viability (10.62 log CFU g^-1 ). The highest survival rate of spray-dried cells was 85.56 ± 7.4%. In addition, the cell viability of spray-dried Lactobacillus rhamnosus with MWPH as culture and dry medium was 0.79 log CFU g^-1 higher than that of HWPH. Images confirmed that spray-dried Lactobacillus rhamnosus in MWPH provided better protection and it showed greater sustained viability after gastrointestinal digestion.

CONCLUSION

Overall, WPH just as carrier provides better thermal protection and MWPH is a preferable two-in-one medium for probiotics. © 2022 Society of Chemical Industry.

Freeze Drying of Polymer Nanoparticles and Liposomes Exploiting Different Saccharide-Based Approaches

Biodegradable nanocarriers represent promising tools for controlled drug delivery. However, one major drawback related to their use is the long-term stability, which is largely influenced by the presence of water in the formulations, so to solve this problem, freeze-drying with cryoprotectants has been proposed. In the present study, the influence of the freeze-drying procedure on the storage stability of poly(lactide-co-glycolide) (PLGA) nanoparticles and liposomes was evaluated. In particular, conventional cryoprotectants were added to PLGA nanoparticle and liposome formulations in various conditions. Additionally, hyaluronic acid (HA), known for its ability to target the CD44 receptor, was assessed as a cryoprotective excipient: it was added to the nanocarriers as either a free molecule or conjugated to a phospholipid to increase the interaction with the polymer or lipid matrix while exposing HA on the nanocarrier surface. The formulations were resuspended and characterized for size, polydispersity index, zeta potential and morphology. It was demonstrated that only the highest percentages of cryoprotectants allowed the resuspension of stable nanocarriers. Moreover, unlike free HA, HA-phospholipid conjugates were able to maintain the particle mean size after the reconstitution of lyophilized nanoparticles and liposomes. This study paves the way for the use of HA-phospholipids to achieve, at the same time, nanocarrier cryoprotection and active targeting.

On the Physical Stability of Leucine-Containing Spray-Dried Powders for Respiratory Drug Delivery

Carrier-free spray-dried dispersions for pulmonary delivery, for which the demand is growing, frequently require the incorporation of dispersibility-enhancing excipients into the formulations to improve the efficacy of the dosage form. One of the most promising of such excipients, L-leucine, is expected to be approved for inhalation soon and has been studied exhaustively. However, during stability, small fibers protruding from the particles of leucine-containing powders have occasionally been observed. To clarify the origin of these fibers and assess their potential influence on the performance of the powders, three different classes of spray-dried leucine-containing formulation systems were studied over an 8-month accelerated stability program. These systems consisted of a large molecule biologic (bevacizumab) in conjunction with a glass former (trehalose), an amorphous small-molecular mass active (moxidectin), and a crystallizing active (mannitol). It was determined that the appearance of the fibers was due to the presence of small quantities of leucine in higher energy states, either because these were amorphous or present as a less stable crystalline polymorph. It was further shown that the growth of these leucine fibers caused no significant physicochemical instability in the powders. Nor, more importantly, did it decrease their aerosol performance in a dry powder inhaler or reduce the concentration of their active pharmaceutical ingredients.