Instability Challenges and Stabilization Strategies of Pharmaceutical Proteins

Synergistic Prevascularization with Proangiogenic Silica Nanoparticles and VEGF-Mimetic Aptamer in Tailored GelMA Hydrogels

Angiogenesis is a crucial and challenging requirement for the regeneration and repair of damaged tissues, particularly for critical-sized ones. To address this challenge, in this study, we fabricated a cell-communicating gelatin methacryloyl (GelMA) hydrogel using core-shell silica nanoparticles conjugated with roxadustat (FG-4592) and a VEGF-mimetic aptamer (Apt02). This hydrogel promotes tube formation and prevascularization synergistically through both extracellular and intracellular pathways in human umbilical vein endothelial cells (HUVEC), with FG-4592 acting via the extracellular pathway and Apt02 via the intracellular pathway. Fluorophore carbon quantum dot was synthesized and used as a core for constructing core-shell amine-functionalized silica nanoparticles (CQD@MSN-NH2). Using human serum albumin (HSA) as a protein linker, FG-4592 was conjugated on the surface of the nanoparticles to the finalized CQD@MSN@HSA@FG-4592 (CMHF) theranostic proangiogenic nanoparticle. Several techniques were used to characterize structural and cytotoxic properties of CMHF nanoparticles. On the other hand, Apt02 was incorporated into the GelMA hydrogel to induce angiogenesis extracellularly. Results showed that the CMHF nanoparticle and Apt02 are cyto-compatible in periodontal ligament fibroblasts (PDLF) and HUVEC. The HUVEC tube formation assay indicated that 1.0 μM Apt02, 20 μM FG-4592, and 35 μg/mL of CMHF individually induced angiogenesis in HUVEC when 10 ng/mL VEGF was used as a positive control. Western blot and quantitative polymerase chain reaction assays of four genes revealed Apt02 to have an extracellular mechanism of action while FG-4592 increases cellular concentration of the hypoxia-inducible factor-1α (Hif-1α) transcription factor intercellularly and recruits HUVEC to form tube-like vessels both in vitro and ex ovo. In summary, our study introduces an injectable hydrogel containing a blend of 5% GelMA, 1.0 μM Apt02, and 35 μg/mL CMHF nanoparticles, which effectively enhances angiogenesis by activating both extracellular (through VEGFR) and intracellular (by Hif-1α overexpression) pathways and is more effective when targeting only one pathway.

Role of hydrogen bonding and water clusters in deamidation of peptide in glycerol-water solutions

The study is part of investigations on relationships between water content, structure, and rates of chemical reactions in amorphous systems. This paper reports Asn deamidation of a hexapeptide in an amorphous liquid matrix, glycerol with water concentration of 1 to 30 wt%, at 50 °C. Using an amorphous liquid system allows focusing on the chemical and structural features of water effects, by minimizing the "molecular mobility" aspect. High-performance liquid chromatography (HPLC) is used to quantify both the loss of the parent compound and the accumulation of the cyclic succinimide intermediate and the hydrolysis products, Asp and iso-Asp. The rate constants for succinimide formation (k1) and succinimide hydrolysis (k2 and k3) are determined by fitting the HPLC data to specific kinetic models. The apparent pH of the solutions is confirmed to be independent of water content by using two orthogonal approaches. The experimental studies are complemented by molecular dynamics (MD) simulations of the hydrogen-bonding network around the Asn. This work reveals two water-content regions with distinct effects on deamidation. The first region shows a nearly constant k1 for water concentrations up to 8 wt%, whereas a significant increase in k1 with increased water content is observed in the second region above 12 wt% water. The water content threshold for the deamidation rate coincides with the spectroscopically determined thresholds for hydrogen bonding and water clustering in glycerol/water mixtures, as reported previously by a range of techniques including Raman spectroscopy. The study highlights relevance of hydrogen bonding and water clustering pattern for chemical processes including deamidation, and provides a basis for follow-up studies on the role of amorphous structure in deamidation in amorphous freeze-dried peptide and protein formulations.

A review on polysaccharide-based tumor targeted drug nanodelivery systems

The tumor-targeted drug delivery system (TTDNS) uses nanocarriers to transport chemotherapeutic agents to target tumor cells or tissues precisely. This innovative approach considerably increases the effective concentration of these drugs at the tumor site, thereby enhancing their therapeutic efficacy. Many chemotherapeutic agents face challenges, such as low bioavailability, high cytotoxicity, and inadequate drug resistance. To address these obstacles, TTDNS comprising natural polysaccharides have gained increasing popularity in the field of nanotechnology owing to their ability to improve safety, bioavailability, and biocompatibility while reducing toxicity. In addition, it enhances permeability and allows for controlled drug delivery and release. This review focuses on the sources of natural polysaccharides and their direct and indirect mechanisms of anti-tumor activity. We also explored the preparation of various polysaccharide-based nanocarriers, including nanoparticles, nanoemulsions, nanohydrogels, nanoliposomes, nanocapsules, nanomicelles, nanocrystals, and nanofibers. Furthermore, this review delves into the versatile applications of polysaccharide-based nanocarriers, elucidating their capabilities for in vivo targeting, controlled release, and responsiveness to endogenous and exogenous stimuli, such as pH, reactive oxygen species, glutathione, light, ultrasound, and magnetic fields. This sophisticated design substantially enhances the chemotherapeutic efficacy of the encapsulated drugs at tumor sites and provides a basis for preclinical and clinical research. However, the in vivo stability, drug loading, and permeability of these preparations into tumor tissues still need to be improved. Most of the currently developed biomarker-sensitive polysaccharide nanocarriers are still in the laboratory stage, more innovative delivery mechanisms and clinical studies are needed to develop commercial nanocarriers for medical use.

Evaluation of stabilizing additives to protect activities of cytochrome P450 enzymes for in vitro drug testing and pharmacogenetic studies: Focus on CYP2D6

In vitro and ex vivo studies on drug metabolism and stability are vital for drug development and pre-clinical safety assessment. Traditional in vitro models, such as liver enzyme (S9) fractions and microsomes, often fail to account for individual variability. Personalized models, including 3D cell models and organoids, offer promising alternatives but may not fully replicate physiological processes, especially for Cytochrome P450 (CYP) families involved in extrahepatic metabolism. A major challenge in these studies is the low stability and expression of CYP enzymes. This study aimed to stabilize native CYP activity in vitro by developing an optimized buffer formulation. Initial experiments using recombinant CYP supersomes and liver microsomes identified 45 μM cysteine, 4 mM dithiothreitol (DTT), and 300 μM phosphocholine (PC) as the most effective stabilizers. The applicability of these stabilizers was subsequently confirmed in primary human brain tissue, where they enabled the successful determination of CYP2D6 activity. This highlights the stabilizing buffer's utility for enhancing CYP functionality in diverse tissue types, including the brain, which plays a critical role in cerebral detoxification and drug metabolism. These findings suggest that specific enzyme stabilization can enable comprehensive evaluations of CYP function in ex vivo tissue samples, advancing the development of organoid human tissue models and supporting drug metabolism research.

Development of Complex Generics and Similar Biological Products: An Industrial Perspective of Reverse Engineering

Generic drugs are developed to be bioequivalent to innovator formulation, matching them in dosage form, safety, strength, quality and efficacy. Known as "interchangeable multi-source pharmaceutical products," generics play a crucial role in reducing therapeutic costs and enhancing patient compliance. Over the past decade, generics have accounted for more than 90% of prescriptions in the U.S., which has driven down the average price of these drugs to nearly match production costs once market competition grows. Simple generics of small-molecule drugs are often produced through trial and error based on existing data, but complex generics require advanced techniques like reverse engineering to replicate the brand drug's release profile. These complex generics include sophisticated drug delivery forms that ensure the therapeutic agent is released gradually, maximizing effectiveness. Conversely, similar biological products highly similar to approved biologics-undergo rigorous analytical and clinical evaluations due to their complexity and the nature of biologic production. The increased demand for similar biological products is driven by expiring biologic patents, economic incentives, and regulatory advancements, with the market expected to grow significantly by 2026. The Biologic Price Competition and Innovation Act (BPCIA) enable abbreviated approvals for similar biological products, promoting affordability. Despite minor differences from original biologics, similar biological products undergo extensive testing to ensure safety and efficacy, following global regulatory guidelines that emphasize strict quality standards. This framework is essential for expanding patient access to effective therapies for conditions like cancer and autoimmune diseases while supporting healthcare sustainability.

Stability and Fibrillation of Lysozyme in the Mixtures of Ionic Liquids with Varying Hydrophobicity

Combinatorial effects of small molecules provide newer avenues to improve protein stability. The combined effect of two different classes of ILs on the stability and fibrillation propensity of lysozyme (Lyz) was investigated. Imidazolium-ILs (an aromatic moiety) with varying alkyl chains, methyl (MIC), butyl (BMIC) and hexyl (HMIC), and pyrrolidinium-IL (alicyclic moiety) with butyl substitution (BPyroBr) were chosen. The fibrillation was delayed by the addition of any of the IL. While added as a mixture with varying molar ratios, the presence of HMIC with MIC or BMIC at the ratio of 2:1 increased the fibrillation time synergistically by increasing lag time and reducing elongation rate. The protein stability was significantly reduced in these conditions compared to lower molar ratios of HMIC with MIC or BMIC. Molecular dynamics simulation studies indicated that upon adding Im-ILs water molecules were reduced around Lyz, whereas BPyroBr slightly increased the water around Lyz. Preferential interaction studies suggest that the preferential binding of HMIC with the protein was the most favored and it synergistically facilitated the preferential binding of MIC. Though BMIC was preferentially binding to the protein, it disfavoured the interaction of MIC. BMIC and BPyroBr had a competitive binding on the surface of Lyz. The results suggested that the mixture of ILs containing the longer alkyl chain destabilizes the protein and delays the fibril formation to a larger extent than the shorter alkyl chain ILs. Further, the effect of aromatic ILs could be greater than alicyclic ILs having the same alkyl chain length.

The role of Gln269Leu mutation on the thermostability and structure of uricase from Aspergillus flavus

Aspergillus flavus Urate oxidase (AFUOX) is promising for potential therapeutic applications, particularly in gout treatment. However, the enzyme's low thermostability and solubility limit its efficacy. A targeted mutation, substituting Gln with Leu at position 269 (Q269L) has been proposed to enhance its stability. The turnover number, catalytic efficiency, and specific activity of Q269L were 3.7 (s-1), 53.2 (mM-1. s-1), and 3.926 U/mg, respectively. In comparison, for the wild type, these were 3.1 (S-1), 35.1 (mM-1. s-1), and 4.018 U/mg, respectively. Notably, the wild type exhibited maximum activity at pH 9 and 25 °C, whereas the activity of Q269L was obtained at pH 9.5 and 30 °C. Furthermore, the half-life of Q269L at 40 °C is significantly longer (85.55 min) compared to the wild-type (49.85 min). The thermodynamic parameters ΔH≠, ΔS≠, and ΔG≠ at 40 °C for Q269L were 60.9 kJ.mol-1, -276 J.mol-1, and 147.3 kJ.mol-1, respectively. Intrinsic fluorescence reductions and ANS fluorescence increases suggest that tryptophan resides in a polar environment with augmented hydrophobic pockets. FTIR analysis of Q269L reveals a decrease in β-sheet and an increase in α-helix structures, supporting molecular dynamics simulations. Collectively, MD and experimental results underscore Q269L's enhanced thermostability and localized structural alterations, advancing AFUOX's therapeutic potential.

Therapeutic Potential of Artemisia campestris Essential Oil: Antioxidant, Anti-Inflammatory, and Anticancer Insights From In Silico Analysis

Artemisia campestris subsp. campestris (tuguft) is a medicinal plant traditionally used in Algerian medicine. This study investigates the chemical composition and bioactivity of its essential oil (ACEO). Gas chromatography-mass spectrometry (GC-MS) analysis identified key compounds, including linalyl acetate (2.92%), geranyl acetate (2.45%), and eucalyptol (1.38%). ACEO demonstrated significant antioxidant activity, with IC50 values of 11.09 μg/mL (DPPH), 15.81 μg/mL (FRAP), and 22.70 μg/mL (β-carotene). It also enhanced peroxidase activity by 82.67 U/g. The anti-inflammatory effects were confirmed with an IC50 of 18.87 μg/mL. Notably, in silico molecular docking revealed that 3-cyclopentyl-N-(2-(3,4-dimethoxyphenyl)ethyl) exhibits strong binding affinity to phosphoinositide 3-kinase gamma, a target for pancreatic cancer therapy, suggesting potential anticancer activity. These findings underscore the therapeutic potential of ACEO, highlighting its antioxidant, anti-inflammatory, and anticancer properties.

Regulatory Guidelines for the Analysis of Therapeutic Peptides and Proteins

Peptides and proteins have become increasingly important in the treatment of various diseases, including infections, metabolic disorders, and cancers. Over the past decades, the number of approved peptide- and protein-based drugs has grown significantly, now accounting for about 25% of the global pharmaceutical market. This increase has been recorded since the introduction of the first therapeutic peptide, insulin, in 1921. Therapeutic peptides and proteins offer several advantages over small molecule drugs, including high specificity, potency, and safety; however, they also face challenges related to instability in liquid formulations. To address this issue, numerous formulation techniques have been developed to enhance their stability. In either state, physical and chemical characterization of the peptide or protein of interest is crucial for ensuring the identity, purity, and activity of these therapeutic agents. Regulatory bodies such as the FDA, ICH, and EMA have established guidelines for the analysis, stability testing, and quality control of peptides and biologics to ensure the safety and effectiveness of these drugs. In the present review, these guidelines and the consequences thereof are summarized and provided to support the notion of developing tailored bioanalytical workflows for each peptide or protein drug.

Protein-Based Degraders: From Chemical Biology Tools to Neo-Therapeutics

The nascent field of targeted protein degradation (TPD) could revolutionize biomedicine due to the ability of degrader molecules to selectively modulate disease-relevant proteins. A key limitation to the broad application of TPD is its dependence on small-molecule ligands to target proteins of interest. This leaves unstructured proteins or those lacking defined cavities for small-molecule binding out of the scope of many TPD technologies. The use of proteins, peptides, and nucleic acids (otherwise known as "biologics") as the protein-targeting moieties in degraders addresses this limitation. In the following sections, we provide a comprehensive and critical review of studies that have used proteins and peptides to mediate the degradation and hence the functional control of otherwise challenging disease-relevant protein targets. We describe existing platforms for protein/peptide-based ligand identification and the drug delivery systems that might be exploited for the delivery of biologic-based degraders. Throughout the Review, we underscore the successes, challenges, and opportunities of using protein-based degraders as chemical biology tools to spur discoveries, elucidate mechanisms, and act as a new therapeutic modality.

Effect of formulation composition on trastuzumab stability

For monoclonal antibody drug products as for other biologics, while the innovator drug products first becomes commercially available, they are often followed by one or more biosimilar products. These biosimilars often differ from the innovator product, as well as from each other, in their formulation composition. However, the impact of the formulation composition on the stability of the active pharmaceutical ingredient subjected to different 'stresses' is still not understood. We have evaluated the effect of different formulations on structural stability and aggregation behavior of a monoclonal antibody, trastuzumab (both the drug substance and the final drug product), against three most common stresses encountered during production, storage, and formulation into a lyophilized product - freeze-thaw, freeze-drying, and agitation. Irrespective of the stabilizer used, the formulations exhibited good conformational stability against all three stresses. However, the freeze-drying process caused a significant increase in the number of soluble aggregates, but only in sucrose containing formulations. On the other hand, agitation in sorbitol containing formulation led to a significant increase in insoluble aggregates. This effect could also be attributed to the absence of surfactant in this formulation composition. The stabilizing effect of trehalose appeared to be independent of its concentration. Therefore, the effect of formulation composition is more pronounced for aggregation of trastuzumab than for its conformational stability. Our findings suggest that formulation design warrants consideration of both conformational stability and aggregation behavior of the active ingredient.

Kinetics of human insulin degradation in the solid-state: An investigation of the effects of temperature and humidity

With the increasing development of oral peptide dosage forms, a comprehensive understanding of factors affecting peptide drug stability in the solid-state is critical. This study used human insulin, as a model peptide, to examine the individual and interactive effects of temperature and humidity on its solid-state stability. Insulin was stored at temperature (25 °C, 40 °C, and 6 °C) and humidity (1 %, 33 % and 75 %) over 6 months. Primary degradation pathways were deamidation and covalent aggregation. Degradation product formation rates were determined empirically and modelled using the humidity-corrected Arrhenius equation. Temperature had a major impact on deamidation and covalent aggregation rates, with the reaction rates increasing with temperature. The effect of humidity was temperature dependent. Moisture induced degradation was minimal at 25 °C and 40 °C, but an important factor at 60 °C. Dynamic vapour sorption analysed determined a clear differences in insulin moisture sorption characteristics at 60 °C relative to 25 °C and 40 °C. The findings suggest that the effect of moisture on insulin deamidation and covalent aggregation rates was not a function of water content but the nature of the insulin moisture interaction.

Biopharmaceutical drug delivery and phototherapy using protein crystals

Biopharmaceutical drugs, including proteins, peptides, and antibodies, are renowned for their high specificity and efficacy, fundamentally transforming disease treatment paradigms. However, their structural complexity presents challenges for their formulation and delivery. Protein crystals, characterized by high purity, high stability and a porous structure for biopharmaceutical drug encapsulation, providing a potential avenue for formulating and delivering biopharmaceutical drugs. There is increasing interest in engineering protein crystals to delivery biopharmaceutical drugs for biomedical applications. This review summarizes the recent advances in biopharmaceutical drug delivery and phototherapy using protein crystals. First, we evaluate the advantages of using protein crystals for biopharmaceutical drugs delivery. Next, we outline the strategies for in vitro and in vivo crystallization to prepare protein crystals. Importantly, the review highlights the advanced applications of protein crystals in biopharmaceutical drug delivery, tumor phototherapy, and other optical fields. Finally, it provides insights into future perspectives of biopharmaceutical drug delivery using protein crystals. This comprehensive review aims to provide effective insights into design of protein crystals to simplify biopharmaceutical drug delivery and improve disease treatment.

Real-time monitoring by interferometric light microscopy of phage suspensions for personalised phage therapy

Phage therapy uses viruses (phages) against antibiotic resistance. Tailoring treatments to specific patient strains requires stocks of various highly concentrated purified phages. It, therefore, faces challenges: titration duration and specificity to a phage/bacteria couple; purification affecting stability; and highly concentrated suspensions tending to aggregate. To address these challenges, interferometric light microscopy (ILM), characterising particles (size, concentration, and visual homogeneity) within minutes, was applied herein to anti-Staphylococcus aureus myovirus phage suspensions. Particle concentration was linearly correlated with phage infectious titre (R2 > 0.97, slope: 3 particles/plaque forming units (PFU)) at various degrees of purification, allowing to approximate the infectious titre for suspensions ≥ 3 × 108 PFU/mL, thereby encompassing most therapeutic doses. Purification narrowed and homogenised particle distribution while maintaining therapeutic concentrations. When compared to dynamic light scattering, electrophoretic mobility, and UV/Visible-spectroscopy, ILM best detected aggregates according to our homemade scoring. Although ILM has certain limitations, such as the inability to detect podoviruses (hydrodynamic diameter < 80 nm), or to measure particles in low-concentrated suspensions (< 108 particles/mL), the present proof-of-concept positions this technique as a valuable quality control tool, as a complement to titration rather than a replacement for this technique, for phage suspensions, paving the way for further investigations.

Advances in conjugate drug delivery System: Opportunities and challenges

Ideal drug delivery system is designed to accurately deliver the drug to its intended site. The development of conjugate drug delivery system introduces a novel pathway to precise drug delivery with advantages over traditional methods. The core of a conjugate drug delivery system comprises a molecule with two functional components, bounded by a linker structure. One component is responsible for delivering or stabilizing the conjugate, while the other is used to provide the therapeutic or diagnostic effects of the bioactivity. Conjugate drug delivery system improves patient health by maintaining the structural stability of drugs in molecular form, delivering therapeutics or diagnostic material to the target site, minimising off-target accumulation and promoting patient compliance. This system includes various types of drug conjugates that modulate drug pharmacokinetics, stability, absorption, and exposure in lesions and healthy tissues. In this review, we focus on the key characteristics and recent advances of various conjugate drug delivery systems and explore their mechanisms. We also point out the current challenges faced by conjugate drug delivery system and look forward to the future prospects.

Exploring the antimicrobial potential of crude peptide extracts from Allium sativum and Allium oschaninii against antibiotic-resistant bacterial strains

CONTEXT

Plant peptides garner attention for their potential antimicrobial properties amid the rising concern over antibiotic-resistant bacteria.

OBJECTIVE

This study investigates the antibacterial potential of crude peptide extracts from 27 Thai plants collected locally.

MATERIALS AND METHODS

Peptide extracts from 34 plant parts, derived from 27 Thai plants, were tested for their antimicrobial efficacy against four highly resistant bacterial strains: Streptococcus aureus MRSA, Pseudomonas aeruginosa, Acinetobacter baumannii, and Escherichia coli. The stability of these peptide extracts was examined at different temperatures, and the synergistic effects of two selected plant peptide extracts were investigated. Additionally, the time-kill kinetics of the individual extracts and their combination were determined against the tested pathogens.

RESULTS

Peptides from Allium sativum L. and Allium oschaninii O. Fedtsch (Amaryllidaceae) were particularly potent, inhibiting bacterial growth with MICs ranging from 1.43 to 86.50 µg/mL. The consistent MICs and MBCs of these extracts across various extraction time points highlight their reliability. Stability tests reveal that these peptides maintain their antimicrobial activity at -20 °C for over a month, emphasizing their durability for future exploration and potential applications in addressing antibiotic resistance. Time-kill assays elucidate the time and concentration-dependent nature of these antimicrobial effects, underscoring their potent initial activity and sustained efficacy over time.

DISCUSSION AND CONCLUSIONS

This study highlights the antimicrobial potential of Allium-derived peptides, endorsing them for combating antibiotic resistance and prompting further investigation into their mechanisms.

Direct Detection of Bound Water in Hydrated Powders of Lysozyme by Differential Scanning Calorimetry

While exploring the behavior of lysozyme powders at different percentages of rehydration by differential scanning calorimetry, we noticed a small peak persistently on the left of the melting point of bulk water, which, when heating up the system, was always around -10 °C. The intensity of the transition was maximal at 160% rehydration and disappeared at higher values. By comparing the premelting peak properties in H2O and D2O, we attributed it to freezable water bound on the protein surface. This is the first time that such an observation has been reported.

Exploring the Inhibitory Potential of Phytosterols β-Sitosterol, Stigmasterol, and Campesterol on 5-Alpha Reductase Activity in the Human Prostate: An In Vitro and In Silico Approach

Steroidal 5α-reductase type 2 (S5αR2) is a key enzyme involved in the conversion of testosterone (TST) to dihydrotestosterone (DHT), a crucial process in the development of benign prostatic hyperplasia (BPH). Phytosterols (PSs), natural plant-derived compounds, have been proposed as potential inhibitors of S5αR2, but studies on their efficacy are limited. This study evaluates the inhibitory effects of three PSs (β-sitosterol, stigmasterol, and campesterol) on S5αR2 activity using a combined in vitro and in silico approach. The inhibitory activity of the respective PSs was assessed in vitro, by measuring TST and DHT, while molecular docking and dynamics explored PS interactions with S5αR2's active site. The in vitro tests indicated significantly higher IC50 values (β-sitosterol, 3.24 ± 0.32 µM; stigmasterol, 31.89 ± 4.26 µM; and campesterol, 15.75 ± 5.56 µM) for PSs compared to dutasteride (4.88 × 10-3 ± 0.33 µM), suggesting a lower efficiency in inhibiting S5αR2. The in silico studies confirmed these observations, explained by the lower binding affinity identified for PSs to the enzyme's active site in the molecular docking studies and the reduced stability of the interactions with the active site of the enzyme during the molecular dynamics simulations compared to dutasteride. The results suggest that PSs exhibit low-to-negligible inhibitory activity against S5αR2 (µM range) compared to the synthetic inhibitor dutasteride (nM range). Among the three PSs studied, β-sitosterol showed the highest inhibitory activity and the best stability in its interaction with S5αR2, when compared with stigmasterol and campesterol.

Nano- and Micro-Platforms in Therapeutic Proteins Delivery for Cancer Therapy: Materials and Strategies

Proteins have emerged as promising therapeutics in oncology due to their great specificity. Many treatment strategies are developed based on protein biologics, such as immunotherapy, starvation therapy, and pro-apoptosis therapy, while some protein biologics have entered the clinics. However, clinical translation is severely impeded by instability, short circulation time, poor transmembrane transportation, and immunogenicity. Micro- and nano-particles-based drug delivery platforms are designed to solve those problems and enhance protein therapeutic efficacy. This review first summarizes the different types of therapeutic proteins in clinical and research stages, highlighting their administration limitations. Next, various types of micro- and nano-particles are described to demonstrate how they can overcome those limitations. The potential of micro- and nano-particles are then explored to enhance the therapeutic efficacy of proteins by combinational therapies. Finally, the challenges and future directions of protein biologics carriers are discussed for optimized protein delivery.

Chaperone/Polymer Complexation of Protein-Based Fluorescent Nanoclusters against Silica Encapsulation-Induced Physicochemical Stresses

Silica encapsulation under ambient conditions is commonly used to shield protein-based nanosystems from chemical stress. However, encapsulation-induced photo- and structural instabilities at elevated temperatures have been overlooked. Using bovine serum albumin-capped fluorescent gold nanoclusters (BSA-AuNCs) as a model, we demonstrated that chaperone/polymer layer-by-layer complexation can stabilize the template to resist encapsulation-induced fragmentation/reorganization and emission increases at 37 °C or higher temperatures. We first wrapped BSA-AuNCs with α-crystallin chaperones (α-Crys) to gain the highest thermal stability at a 1:50 molar ratio and then enfolded BSA-AuNC/α-Crys with thermoresponsive poly-N-isopropylacrylamide (PNIPAM) at 60 °C to shield silica interaction and increase the chaperone-client protein accessibility. The resulting BSA-AuNC/α-Crys/PNIPAM (BαP) was encapsulated by a sol-gel process to yield BαP-Si (∼80 ± 4.5 nm), which exhibited excellent structural integrity and photostability against chemical and thermal stresses. Moreover, targeted BαP-Si demonstrated prolonged fluorescence stability for cancer cell imaging. This template stabilization strategy for silica encapsulation is biocompatible and applicable to other protein-based nanosystems.

Assessment of the antibacterial and antioxidant activities of seaweed-derived extracts

In swine farming, animals develop diseases that require the use of antibiotics. In-feed antibiotics as growth promoters have been banned due to the increasing concern of antimicrobial resistance. Seaweeds offer bioactive molecules with antibacterial and antioxidant properties. The aim was to estimate the in vitro properties of seaweed extracts: Ascophyllum nodosum (AN), Palmaria palmata (PP), Ulva lactuca (UL), and 1:1 mixes (ANPP, ANUL, PPUL). Escherichia coli strains were used to test for growth inhibitory activity, and chemical-based assays were performed for antioxidant properties. The treatments were 2 (with/without Escherichia coli) × 2 (F4 + and F18 +) × 5 doses (0, 1.44, 2.87, 5.75, 11.50, and 23.0 mg/mL). Bacteria were supplemented with seaweed extracts, and growth was monitored. The antioxidant activity was assessed with 6 doses (0, 1, 50, 100, 200, 500, and 600 mg/mL) × 6 compounds using two chemical assays. Data were evaluated through SAS. The results showed that AN and UL significantly inhibited (p < 0.05) the growth of F4 + and F18 +. PP and mixes did not display an inhibition of the bacteria growth. AN, PP, UL extracts, and mixes exhibited antioxidant activities, with AN showing the strongest dose-response. Thus, AN and UL seaweed extracts reveal promising antibacterial and antioxidant effects and may be candidates for in-feed additives.

Integrating Computational Design and Experimental Approaches for Next-Generation Biologics

Therapeutic protein engineering has revolutionized medicine by enabling the development of highly specific and potent treatments for a wide range of diseases. This review examines recent advances in computational and experimental approaches for engineering improved protein therapeutics. Key areas of focus include antibody engineering, enzyme replacement therapies, and cytokine-based drugs. Computational methods like structure-based design, machine learning integration, and protein language models have dramatically enhanced our ability to predict protein properties and guide engineering efforts. Experimental techniques such as directed evolution and rational design approaches continue to evolve, with high-throughput methods accelerating the discovery process. Applications of these methods have led to breakthroughs in affinity maturation, bispecific antibodies, enzyme stability enhancement, and the development of conditionally active cytokines. Emerging approaches like intracellular protein delivery, stimulus-responsive proteins, and de novo designed therapeutic proteins offer exciting new possibilities. However, challenges remain in predicting in vivo behavior, scalable manufacturing, immunogenicity mitigation, and targeted delivery. Addressing these challenges will require continued integration of computational and experimental methods, as well as a deeper understanding of protein behavior in complex physiological environments. As the field advances, we can anticipate increasingly sophisticated and effective protein therapeutics for treating human diseases.

Enhancing protein stability under stress: osmolyte-based deep eutectic solvents as a biocompatible and robust stabilizing medium for lysozyme under heat and cold shock

In biomedical and biotechnological domains, liquid protein formulations are vital tools, offering versatility across various fields. However, maintaining protein stability in a liquid form presents challenges due to environmental factors, driving research to refine formulations for broader applications. In our recent study, we investigated the relationship between deep eutectic solvents (DESs) and the natural presence of osmolytes in specific combinations, showcasing the effectiveness of a bioinspired osmolyte-based DES in stabilizing a model protein. Recognizing the need for a more nuanced understanding of osmolyte-based DES stabilization capabilities under different storage conditions, here we broadened the scope of our osmolyte-based DES experimental screening, and delved deeper into structural changes in the enzyme under these conditions. We subjected lysozyme solutions in DESs based on various kosmotropic osmolytes (TMAO, betaine, sarcosine, DMSP, ectoine, GPC, proline, sorbitol and taurine) paired either with another kosmotropic (glycerol) or with chaotropic osmolyte urea to rigorous conditions: heat shock (at 80 °C) and repetitive freeze-thaw cycles (at -20 and -80 °C). Changes in enzyme activity, colloidal stability, and conformational alterations were then monitored using bioassays, aggregation tests, and spectroscopic techniques (FT-IR and CD). Our results demonstrate the remarkable effectiveness of osmolyte-based DES in stabilizing lysozyme under stress conditions, with sarcosine- and betaine-based DESs containing glycerol as a hydrogen bond donor showing the highest efficacy, even at high enzyme loadings up to 200 mg ml-1. Investigation of the individual and combined effects of the DES components on enzyme stability confirmed the synergistic behavior of the kosmotrope-urea mixtures and the cumulative effects in kosmotrope-glycerol mixtures. Additionally, we have shown that the interplay between the enzyme's active and stable (but inactive) states is highly influenced by the water content in DESs. Finally, toxicity assessments of osmolyte-based DESs using cell lines (Caco-2, HaCaT, and HeLa) revealed no risks to human health.

Stability of Protein Pharmaceuticals: Recent Advances

There have been significant advances in the formulation and stabilization of proteins in the liquid state over the past years since our previous review. Our mechanistic understanding of protein-excipient interactions has increased, allowing one to develop formulations in a more rational fashion. The field has moved towards more complex and challenging formulations, such as high concentration formulations to allow for subcutaneous administration and co-formulation. While much of the published work has focused on mAbs, the principles appear to apply to any therapeutic protein, although mAbs clearly have some distinctive features. In this review, we first discuss chemical degradation reactions. This is followed by a section on physical instability issues. Then, more specific topics are addressed: instability induced by interactions with interfaces, predictive methods for physical stability and interplay between chemical and physical instability. The final parts are devoted to discussions how all the above impacts (co-)formulation strategies, in particular for high protein concentration solutions.'

Chitosan/Alginate-Based Nanoparticles for Antibacterial Agents Delivery

Nanoparticle systems integrating alginate and chitosan emerge as a promising avenue to tackle challenges in leveraging the potency of pharmacological active agents. Owing to their intrinsic properties as polysaccharides, alginate and chitosan, exhibit remarkable biocompatibility, rendering them conducive to bodily integration. By downsizing drug particles to the nano-scale, the system enhances drug solubility in aqueous environments by augmenting surface area. Additionally, the system orchestrates extended drug release kinetics, aligning well with the exigencies of chronic drug release requisite for antibacterial therapeutics. A thorough scrutiny of existing literature underscores a wealth of evidence supporting the utilization of the alginate-chitosan nanoparticle system for antibacterial agent delivery. Literature reviews present abundant evidence of the utilization of nanoparticle systems based on a combination of alginate and chitosan for antibacterial agent delivery. Various experiments demonstrate enhanced antibacterial efficacy, including an increase in the inhibitory zone diameter, improvement in the minimum inhibitory concentration, and an enhancement in the bacterial reduction rate. This enhancement in efficacy occurs due to mechanisms involving increased solubility resulting from particle size reduction, prolonged release effects, and enhanced selectivity towards bacterial cell walls, stemming from ionic interactions between positively charged particles and teichoic acid on bacterial cell walls. However, clinical studies remain limited, and there are currently no marketed antibacterial drugs utilizing this system. Hence, expediting clinical efficacy validation is crucial to maximize its benefits promptly.

Biomaterials for Protein Delivery: Opportunities and Challenges to Clinical Translation

The development of biomaterials for protein delivery is an emerging field that spans materials science, bioengineering, and medicine. In this review, we highlight the immense potential of protein-delivering biomaterials as therapeutic options and discuss the multifaceted challenges inherent to the field. We address current advancements and approaches in protein delivery that leverage stimuli-responsive materials, harness advanced fabrication techniques like 3D printing, and integrate nanotechnologies for greater targeting and improved stability, efficacy, and tolerability profiles. We also discuss the demand for highly complex delivery systems to maintain structural integrity and functionality of the protein payload. Finally, we discuss barriers to clinical translation, such as biocompatibility, immunogenicity, achieving reliable controlled release, efficient and targeted delivery, stability issues, scalability of production, and navigating the regulatory landscape for such materials. Overall, this review summarizes insights from a survey of the current literature and sheds light on the interplay between innovation and the practical implementation of biomaterials for protein delivery.

Biophysical and biochemical characterization of a recombinant Lyme disease vaccine antigen, CspZ-YA

Lyme disease, caused by Lyme Borrelia spirochetes, is the most common vector-borne illness in the United States. Despite its global significance, with an estimated 14.5 % seroprevalence, there is currently no licensed vaccine. Previously, we demonstrated that CspZ-YA protein conferred protection against Lyme Borrelia infection, making it a promising vaccine candidate. However, such a protein was tagged with hexahistidine, and thus not preferred for vaccine development; furthermore, the formulation to stabilize the protein was understudied. In this work, we developed a two-step purification process for tag-free E. coli-expressed recombinant CspZ-YA. We further utilized various bioassays to analyze the protein and determine the suitable buffer system for long-term storage and formulation as a vaccine immunogen. The results indicated that a buffer with a pH between 6.5 and 8.5 stabilized CspZ-YA by reducing its surface hydrophobicity and colloidal interactions. Additionally, low pH values induced a change in local spatial conformation and resulted in a decrease in α-helix content. Lastly, an optimal salinity of 22-400 mM at pH 7.5 was found to be important for its stability. Collectively, this study provides a fundamental biochemical and biophysical understanding and insights into the ideal stabilizing conditions to produce CspZ-YA recombinant protein for use in vaccine formulation and development.

Removal of plant endogenous proteins from tobacco leaf extract by freeze-thaw treatment for purification of recombinant proteins

Plants are useful as a low-cost source for producing biopharmaceutical proteins. A significant hurdle in the production of recombinant proteins in plants, however, is the complicated process of removing plant-derived components. Removing endogenous plant proteins, including ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), a major photosynthetic plant enzyme that catalyzes photosynthesis through carboxylation and oxygenation, is important for the purification of recombinant plant proteins. In particular, RuBisCO accounts for 50% of the soluble leaf protein; thus, the removal of RuBisCO is critical for the purification of recombinant proteins from plant materials. An effective conventional method, known as freeze-thaw treatment, was developed for the removal of RuBisCO from Nicotiana benthamiana, which expresses recombinant green fluorescent protein (GFP). Crude extracts or supernatants were frozen at - 30 °C. Upon thawing, most of the RuBisCO was precipitated by centrifugation without significant inactivation and/or yield reduction of GFP. Based on the proteomics analysis, using this method, RuBisCO large and small subunits were reduced to approximately 10% and 20% of those of the unfrozen supernatant solutions, respectively, without the need for specific reagents or equipment. The proteomic analysis also revealed that many ribosomal proteins were removed from the extracts. This method improves the purification process of recombinant proteins from plant materials. Prolonged freezing damaged recombinant β-glucuronidase (GUS), suggesting that the applicability of this treatment should be carefully considered for each recombinant protein.

Roadmap for Drug Product Development and Manufacturing of Biologics

Therapeutic biology encompasses different modalities, and their manufacturing processes may be vastly different. However, there are many similarities that run across the different modalities during the drug product (DP) development process and manufacturing. Similarities include the need for Quality Target Product Profile (QTTP), analytical development, formulation development, container/closure studies, drug product process development, manufacturing and technical requirements set out by numerous regulatory documents such as the FDA, EMA, and ICH for pharmaceuticals for human use and other country specific requirements. While there is a plethora of knowledge on studies needed for development of a drug product, there is no specific guidance set out in a phase dependent manner delineating what studies should be completed in alignment with the different phases of clinical development from pre-clinical through commercialization. Because of this reason, we assembled a high-level drug product development and manufacturing roadmap. The roadmap is applicable across the different modalities with the intention of providing a unified framework from early phase development to commercialization of biologic drug products.

The Effects of Excipients on Freeze-dried Monoclonal Antibody Formulation Degradation and Sub-Visible Particle Formation during Shaking

PURPOSES

We previously reported an unexpected phenomenon that shaking stress could cause more protein degradation in freeze-dried monoclonal antibody (mAb) formulations than liquid ones (J Pharm Sci, 2022, 2134). The main purposes of the present study were to investigate the effects of shaking stress on protein degradation and sub-visible particle (SbVP) formation in freeze-dried mAb formulations, and to analyze the factors influencing protein degradation during production and transportation.

METHODS

The aggregation behavior of mAb-X formulations during production and transportation was simulated by shaking at a rate of 300 rpm at 25°C for 24 h. The contents of particles and monomers were analyzed by micro-flow imaging, dynamic light scattering, size exclusion chromatography, and ultraviolet - visible (UV-Vis) spectroscopy to compare the protective effects of excipients on the aggregation of mAb-X.

RESULTS

Shaking stress could cause protein degradation in freeze-dried mAb-X formulations, while surfactant, appropriate pH, polyol mannitol, and high protein concentration could impact SbVP generation. Water content had little effect on freeze-dried protein degradation during shaking, as far as the water content was controlled in the acceptable range as recommended by mainstream pharmacopoeias (i.e., less than 3%).

CONCLUSIONS

Shaking stress can reduce the physical stability of freeze-dried mAb formulations, and the addition of surfactants, polyol mannitol, and a high protein concentration have protective effects against the degradation of model mAb formulations induced by shaking stress. The experimental results provide new insight for the development of freeze-dried mAb formulations.

Modular and tunable alternative surfactants for biopharmaceuticals provide insights into Surfactant's Structure-Function relationship

Surface-induced aggregation of protein therapeutics is opposed by employing surfactants, which are ubiquitously used in drug product development, with polysorbates being the gold standard. Since poloxamer 188 is currently the only generally accepted polysorbate alternative, but cannot be ubiquitously applied, there is a strong need to develop surfactant alternatives for protein biologics that would complement and possibly overcome known drawbacks of existing surfactants. Yet, a severe lack of structure-function relationship knowledge complicates the development of new surfactants. Herein, we perform a systematic analysis of the structure-function relationship of three classes of novel alternative surfactants. Firstly, the mode of action is thoroughly characterized through tensiometry, calorimetry and MD simulations. Secondly, the safety profiles are evaluated through cell-based in vitro assays. Ultimately, we could conclude that the alternative surfactants investigated possess a mode of action and safety profile comparable to polysorbates. Moreover, the biophysical patterns elucidated here can be exploited to precisely tune the features of future surfactant designs.

Streamlined construction of robust heteroprotein complexes by self-induced in-cell disulfide pairing

Biomolecules and their functional subdomains are essential building blocks in the creation of multifunctional nanocomplexes. Methyl-binding domain protein 2 (MBD2) and p66α stand out as small α-helical motifs with an ability to self-assemble into a heterodimeric coiled-coil, making them promising building units. Yet, their practical use is hindered by rapid dissociation upon dilution. In this study, novel fusion tags, MBD2 and p66α variants, were developed to covalently link during co-expression in E. coli SHuffle. Through strategic placement of cysteine at each α-helix's terminus, intracellular crosslinking occurred with high specificity and yield, facilitated by preserved α-helical interactions. This instant disulfide bonding in the oxidative cytoplasm of E. coli SHuffle efficiently overcame the need for inefficient in vitro oxidation and protein extraction prone to creating non-specific adducts and suboptimal bioprocesses. In contrast to their wild-type counterparts, the GFP-mCherry protein complex cross-linked by the fusion tags maintained the heterodimeric state even under extensive dilution. The fusion tags, when combined with the E. coli SHuffle system, allowed for the streamlined co-expression of a stable protein complex through self-induced intracellular cysteine coupling. The approach demonstrated herein holds great promise for producing multifunctional and robust heteroprotein complexes.

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.

Site-Specific Structural Changes in Long-Term-Stressed Monoclonal Antibody Revealed with DEPC Covalent-Labeling and Quantitative Mass Spectrometry

Studies of structural changes in mAbs under forced stress and storage conditions are essential for the recognition of degradation hotspots, which can be further remodeled to improve the stability of the respective protein. Herein, we used diethyl pyrocarbonate (DEPC)-based covalent labeling mass spectrometry (CL-MS) to assess structural changes in a model mAb (SILuMAb). Structural changes in the heat-stressed mAb samples were confirmed at specific amino acid positions from the DEPC label mass seen in the fragment ion mass spectrum. The degree of structural change was also quantified by increased or decreased DEPC labeling at specific sites; an increase or decrease indicated an unfolded or aggregated state of the mAb, respectively. Strikingly, for heat-stressed SILuMAb samples, an aggregation-prone area was identified in the CDR region. In the case of longterm stress, the structural consequences for SILuMAb samples stored for up to two years at 2-8 °C were studied with SEC-UV and DEPC-based CL-MS. While SEC-UV analysis only indicated fragmentation of SILuMAb, DEPC-based CL-MS analysis further pinpointed the finding to structural disturbances of disulfide bonds at specific cysteines. This emphasized the utility of DEPC CL-MS for studying disulfide rearrangement. Taken together, our data suggests that DEPC CL-MS can complement more technically challenging methods in the evaluation of the structural stability of mAbs.

Exploring non-equilibrium processes and spatio-temporal scaling laws in heated egg yolk using coherent X-rays

The soft-grainy microstructure of cooked egg yolk is the result of a series of out-of-equilibrium processes of its protein-lipid contents; however, it is unclear how egg yolk constituents contribute to these processes to create the desired microstructure. By employing X-ray photon correlation spectroscopy, we investigate the functional contribution of egg yolk constituents: proteins, low-density lipoproteins (LDLs), and yolk-granules to the development of grainy-gel microstructure and microscopic dynamics during cooking. We find that the viscosity of the heated egg yolk is solely determined by the degree of protein gelation, whereas the grainy-gel microstructure is controlled by the extent of LDL aggregation. Overall, protein denaturation-aggregation-gelation and LDL-aggregation follows Arrhenius-type time-temperature superposition (TTS), indicating an identical mechanism with a temperature-dependent reaction rate. However, above 75 °C TTS breaks down and temperature-independent gelation dynamics is observed, demonstrating that the temperature can no longer accelerate certain non-equilibrium processes above a threshold value.

The role of peptides in reversing chemoresistance of breast cancer: current facts and future prospects

Breast cancer is the first malignant tumor in women, and its incidence is also increasing year by year. Chemotherapy is one of the standard therapies for breast cancer, but the resistance of breast cancer cells to chemotherapy drugs is a huge challenge for the effective treatment of breast cancer. At present, in the study of reversing the drug resistance of solid tumors such as breast cancer, peptides have the advantages of high selectivity, high tissue penetration, and good biocompatibility. Some of the peptides that have been studied can overcome the resistance of tumor cells to chemotherapeutic drugs in the experiment, and effectively control the growth and metastasis of breast cancer cells. Here, we describe the mechanism of different peptides in reversing breast cancer resistance, including promoting cancer cell apoptosis; promoting non-apoptotic regulatory cell death of cancer cells; inhibiting the DNA repair mechanism of cancer cells; improving the tumor microenvironment; inhibiting drug efflux mechanism; and enhancing drug uptake. This review focuses on the different mechanisms of peptides in reversing breast cancer drug resistance, and these peptides are also expected to create clinical breakthroughs in promoting the therapeutic effect of chemotherapy drugs in breast cancer patients and improving the survival rate of patients.