RESUMO
In the clinical application of freeze-dried highly concentrated omalizumab formulations, extensive visible bubbles (VBs) can be generated and remain for a long period of time in the reconstitution process, which greatly reduces the clinical use efficiency. It is necessary to understand the forming and breaking mechanism of VBs in the reconstitution process, which is a key factor for efficient and safe administration of biopharmaceutical injection. The effects of different thermal treatments on the volume of VBs and stability of omalizumab, mAb-1, and mAb-2 were investigated. The internal microvoids of the cake were characterized by scanning electron microscopy and mercury intrusion porosimetry. Electron paramagnetic resonance was applied to obtain the molecular mobility of the protein during annealing. A large number of VBs were generated in the reconstitution process of unannealed omalizumab and remained for a long period of time. When annealing steps were added, the volume of VBs was dramatically reduced. When annealed at an aggressive temperature (i.e., -6 °C), although the volume of VBs decreased, the aggregation and acidic species increased significantly. Thus, our observations highlight the importance of setting an additional annealing step with a suitable temperature, which contributes to reducing the VBs while maintaining the stability of the high concentration freeze-dried protein formulation.
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Omalizumab , Proteínas , Temperatura , Liofilização , Estabilidade de MedicamentosRESUMO
PURPOSES: Highly concentrated monoclonal antibody (mAb) formulations for subcutaneous administration are becoming increasingly preferred within the biopharmaceutical industry for ease of use and improved patient compliance. A common phenomenon observed in the industry is that osmolality detected via freezing-point depression (FPD) in high-concentration mAb formulations is much higher than the theoretical concentrations, yet the occurrence of this phenomenon and its possible safety issues have been rarely reported. METHODS: The current study summarized theoretical osmolality of U.S. Food and Drug Administration approved high-concentration mAb formulations and evaluated effects of high osmolality on safety using hemolysis experiments for the first time. Two mAbs formulated at 150 mg/mL were used as models and configured into two isotonic solutions: a, a theoretically calculated molarity in the isotonic range (H) and b, an osmolality value measured via the FPD in the isotonic range (I). The H and I formulations of each mAb were individually subjected to hemolysis experiments, and the hemolysis rates of the two formulations of the same mAb were compared. Besides, the effect of mAb concentration on osmolality detected by FPD was explored as well. RESULTS: The results indicated that the hemolysis rates were similar between the H and I formulations of mAbs at the same sample addition volume, and the osmolality values increased approximately linearly with the increase in mAb concentration. CONCLUSIONS: High osmolality for high-concentration mAb formulations would not affect product safety and the excipients could be added at relatively high levels to maintain product stability, especially for labile products.
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Anticorpos Monoclonais , Hemólise , Humanos , Composição de Medicamentos , Excipientes , Concentração OsmolarRESUMO
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.
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Anticorpos Monoclonais , Química Farmacêutica , Anticorpos Monoclonais/química , Química Farmacêutica/métodos , Excipientes/química , Liofilização/métodos , Manitol , Água , Estabilidade de MedicamentosRESUMO
BACKGROUND: In recent years, road traffic safety has become a prominent issue due to the worldwide proliferation of vehicles on roads. The challenge of driver fatigue detection involves balancing the efficiency and accuracy of the detection process. While various detection methods are available, electroencephalography (EEG) is considered the gold standard due to its high precision in terms of detecting fatigue. However, deep learning models for EEG-based fatigue detection are limited by their large numbers of parameters and low computational efficiency levels, making it difficult to implement them on mobile devices. METHODS: To overcome this challenge, an attention-based Ghost-LSTM neural network (AGL-Net) is proposed for EEG-based fatigue detection in this paper. AGL-Net utilizes an attention mechanism to focus on relevant features and incorporates Ghost bottlenecks to efficiently extract spatial EEG fatigue information. Temporal EEG fatigue features are extracted using a long short-term memory (LSTM) network. We establish two types of models: regression and classification models. In the regression model, we use linear regression to obtain regression values. In the classification model, we classify features based on the predicted values obtained from regression. RESULTS: AGL-Net exhibits improved computational efficiency and a more lightweight design than existing deep learning models, as evidenced by its floating-point operations per second (FLOPs) and Params values of 2.67 M and 103,530, respectively. Furthermore, AGL-Net achieves an average accuracy of approximately 87.3% and an average root mean square error (RMSE) of approximately 0.0864 with the Shanghai Jiao Tong University (SJTU) Emotion EEG Dataset (SEED)-VIG fatigued driving dataset, indicating its advanced performance capabilities. CONCLUSIONS: The experiments conducted with the SEED-VIG dataset demonstrate the feasibility and advanced performance of the proposed fatigue detection method. The effectiveness of each AGL-Net module is verified through thorough ablation experiments. Additionally, the implementation of the Ghost bottleneck module greatly enhances the computational efficiency of the model. Overall, the proposed method has higher accuracy and computational efficiency than prior fatigue detection methods, demonstrating its considerable practical application value.
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Emoções , Redes Neurais de Computação , Humanos , China , Eletroencefalografia/métodos , Modelos LinearesRESUMO
Capillary electrophoresis with sodium dodecyl sulfate (CE-SDS) is a common analytical technique for investigating the purity and molecular size heterogeneity of monoclonal antibody (mAb) drugs. In reducing CE-SDS analysis of mAb-A, the light chain (LC) peak exhibited severe tailing, seriously affecting the purity analysis. The purposes of this investigation are to clarify the source of tailing and develop a more appropriate CE-SDS method to eliminate LC tailing. The degree of LC tailing was closely related to the mAb concentration, SDS concentration, and injection amount, and more hydrophobic detergents, such as sodium hexadecyl sulfate (SHS) and sodium tetradecyl sulfate (STS), could be used instead of SDS to obtain better peak shapes. The results also indicated that the tailing was caused by the binding problem associated with SDS, and SHS/STS could provide a more stable and uniform complexation for the LC. In summary, the method we developed successfully eliminated the LC tailing and provided a robust characterization of mAb-A in reducing CE-SDS analysis.
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Anticorpos Monoclonais , Tetradecilsulfato de Sódio , Anticorpos Monoclonais/análise , Detergentes , Eletroforese Capilar/métodos , Sódio , Dodecilsulfato de Sódio/química , SulfatosRESUMO
This manuscript describes the formation of an artifact shoulder peak with a slightly larger retention time than the main peak under the standard non-reduced capillary electrophoresis with sodium dodecyl sulfate (nrCE-SDS) analysis of a therapeutic recombinant protein X, and clarifies the formation mechanism of the artifact caused by N-ethylmaleimide (NEM) during the sample preparation procedure. A design of experiment (DoE) approach was used to investigate the impact of the factors on the formation of the impurity. Additionally, orthogonal analytical experiments were performed to study the root cause of this phenomenon. The results consistently suggested that the Michael addition reaction between NEM and lysine residues in protein X, and decreased electrophoretic mobility due to increased molecular weight, was the root cause for the artifact, which could be partially inhibited by modifications of incubation conditions. Thus, before performing the nrCE-SDS method, the effects of alkylation reagents and sample preparation procedure on analytical results need to be considered seriously.
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Artefatos , Eletroforese Capilar , Alquilação , Eletroforese Capilar/métodos , Eletroforese em Gel de Poliacrilamida , Etilmaleimida , Indicadores e Reagentes , Dodecilsulfato de Sódio/químicaRESUMO
PURPOSES: This article describes an interesting phenomenon in which optimized freeze-dried (FD) biopharmaceutical formulations are generally more prone to degradation than their liquid counterparts during dropping and proposes an underlying cause for this surprising phenomenon. METHODS: Two monoclonal antibodies (mAbs) and a fusion protein (FP) were used as model biopharmaceuticals. The stability after dropping stress was determined by ultraviolet-visible (UV-Vis), size exclusion high-performance liquid chromatography (SE-HPLC), micro-flow imaging (MFI), and dynamic light scattering (DLS). RESULTS: Contrary to what we would normally assume, the FD formulations of the three biopharmaceuticals studied here generally showed much higher amounts of protein sub-visible particles (SbVPs) than liquid formulations after applying the same dropping stress as determined by MFI and DLS. Traditional techniques, such as UV-Vis and SE-HPLC, could hardly detect such degradation. CONCLUSIONS: We propose that the higher temperature caused by dropping for the FD powders than the liquid formulations was probably one of the root causes for the higher amount of particles formed for the FD powders. We also recommend that dropping stress should be included for early-stage screening and choosing liquid versus FD biopharmaceutical formulations.
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Produtos Biológicos , Anticorpos Monoclonais/química , Estabilidade de Medicamentos , Liofilização , PósRESUMO
PURPOSES: The primary objectives of this study were to investigate the degradation mechanisms of freeze-dried monoclonal antibody (mAb) formulations under mechanical grinding, assess the sensitivity and suitability of various particle analysis techniques, analyze the structure of the collected subvisible particles (SbVPs), and analyze the antioxidant mechanism of methionine (Met) under degradation process to gain a thorough understanding of the phenomenon. METHODS: The freeze-dried mAb-X formulations underwent grinding, and the resultant SbVPs were characterized through visual inspection, flow imaging microscopy, dynamic light scattering, ultraviolet-visible spectroscopy, and size-exclusion high-performance liquid chromatography. We further evaluated the effect of different temperatures and the free radical scavenger Met on SbVP formation. The produced free radicals were detected using electron paramagnetic resonance, and Met S-oxide formation was detected using liquid chromatography-mass spectrometry. In addition, we analyzed the obtained SbVPs using capillary electrophoresis sodium dodecyl sulfate and Fourier transform infrared spectroscopy. RESULTS: Grinding leads to SbVP formation under high temperature and free radical formation. Free radicals produced during grinding require the participation of a macromolecule. Met could then bind to the produced free radicals, thus partially protecting mAb-X from degradation while itself undergoing oxidation to form Met(O). Sensitivity differences between different particle analysis techniques were evaluated, and the obtained SbVPs showed significant changes in secondary structure and the formation of covalent aggregates and fragments. CONCLUSIONS: Met plays the role of an antioxidant in protecting macromolecules by quenching the free radicals produced during grinding. To thoroughly characterize SbVPs, multiple and orthogonal particle analysis techniques should be used, and if necessary, SbVPs should be processed by enrichment to accurately analyze primary and high order structures.
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Anticorpos Monoclonais/química , Sequestradores de Radicais Livres/química , Radicais Livres/metabolismo , Liofilização , Metionina/química , Composição de Medicamentos , Estabilidade de Medicamentos , Estabilidade Proteica , Fatores de TempoRESUMO
PURPOSES: In reducing capillary electrophoresis sodium dodecyl sulfate (CE-SDS) analysis of a monoclonal antibody (mAb-1), the peak area ratio of heavy chain (HC) to light chain (LC) was out of balance, while multiple artifact peaks were observed following the migration of HC. The main purposes of this study were to describe the techniques utilized to eliminate this artifact and clarify the root cause for this interesting phenomenon. METHODS: We optimized the CE-SDS analysis of mAb-1 by a vairety of techniques including changing the concentration of protein or replacing SDS with a more hydrophobic surfactant (i.e., sodium hexadecyl sulfate (SHS) or sodium tetradecyl sulfate (STS) instead of SDS) in sample and/or the sieving gel buffer. Dynamic light scattering (DLS) and reversed phase high-performance liquid chromatography (RP-HPLC) were used to study the protein-surfactant complex. RESULTS: The artifact could be partially mitigated by reducing the protein concentration and replacing SDS with SHS or STS in the sample and/or the sieving gel buffer solutions. Due to replacing a more hydrophobic surfactant, the HC-surfactant complex formed was more resistant to dissociation, preventing additional hydrophobic HC-HC interaction and aggregation, thus eliminating the artifact problem. CONCLUSIONS: DLS and RP-HPLC are powerful supplementary techniques in characterizing the protein-surfactant complex, and hydrophobic surfactants such as SHS and STS could afford more normal electropherograms during the analysis of mAbs.
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Anticorpos Monoclonais , Artefatos , Anticorpos Monoclonais/química , Cromatografia Líquida de Alta Pressão/métodos , Difusão Dinâmica da Luz , Eletroforese Capilar/métodos , Dodecilsulfato de Sódio/química , TensoativosRESUMO
PURPOSES: Liquid protein-based biopharmaceutical formulations have been reported to form aggregation and protein sub-visible particles (SbVPs) during dropping (Randolph et al., J Pharm Sci 2015, 104, 602). However, effects of secondary package on liquid biopharmaceutical formulation stability during dropping are overlooked and have not been reported so far. This study reports the first real-world evaluation on effects of secondary package on liquid biopharmaceutical formulation stability during dropping, using two monoclonal antibodies (mAb-1 and mAb-2) and one fusion protein (FP-1) as model biopharmaceuticals. METHODS: The potential protective effects of secondary package and formulation composition on liquid biopharmaceutical formulations during dropping were evaluated with micro-flow imaging (MFI) and dynamic light scattering (DLS). RESULTS: The dropping-induced degradation could be detected with the two sensitive particle analyzing techniques MFI and DLS. Formulation compositions have dramatic impact on biopharmaceutical stability during dropping. Surprisingly, unlike the primary packages that have been reported to impact liquid biopharmaceutical stability, the secondary packaging system as described in our current preliminary design has little or no protective effect during dropping. CONCLUSIONS: Our study is the first real-world data showing that the secondary package system has little to no effect on the liquid biopharmaceutical formulation quality during dropping. On the contrary, the stability of liquid biopharmaceutical formulations during dropping is more relevant to formulation compositions and primary packages.
Assuntos
Produtos Biológicos/química , Embalagem de Medicamentos , Anticorpos Monoclonais/química , Composição de Medicamentos , Estabilidade de Medicamentos , Difusão Dinâmica da LuzRESUMO
PURPOSES: The main purposes of this article are to describe an unprecedented phenomenon in which significant amount of a shoulder peak impurity was observed during normal non-reducing capillary electrophoresis-sodium dodecyl sulfate (CE-SDS) analysis of a recombinant fusion protein X, and to evaluate the root cause for this phenomenon. METHODS: A series of experiments were conducted to study the nature of this degradation. Effects of iodoacetamide (IAM), heating temperature, duration, and SDS on the formation of this specific impurity were evaluated using a variety of characterization techniques. RESULTS: The formation of the impurity as observed in CE-SDS was actually due to alkylation of lysine and serine residues with IAM, as confirmed by peptide mapping and LC-MS/MS, which increased the molecular weight and therefore decreased the electrophoretic mobility. The amount of impurity was also strongly dependent on sample preparation conditions including the presence or absence of SDS. CONCLUSIONS: Our study clearly suggested that even though IAM has been used extensively as an alkylation reagent in the traditional non-reducing CE-SDS analysis of monoclonal antibodies and other proteins, alkylation with IAM could potentially lead to additional impurity peak, and therefore complicating analysis. Therefore, before performing CE-SDS and other analyses, the effects of sample preparation procedures on analytical results must be evaluated. For protein X, IAM should be excluded for CE-SDS analysis.
Assuntos
Proteínas Recombinantes/química , Dodecilsulfato de Sódio/química , Anticorpos Monoclonais/química , Cromatografia Líquida/métodos , Eletroforese Capilar/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Espectrometria de Massas em Tandem/métodosRESUMO
PURPOSE: The main purposes of this manuscript are to report a surprising and interesting degradation reaction of glucagon from a specific vendor in which glucagon underwent cleavage among several peptide bonds quickly under near neutral to basic conditions, and to propose the root cause of mechanism for the degradation reaction. METHODS: The degradation reaction was monitored by HPLC and the fragment structures were confirmed by LC-MS. Possible impurities responsible for the degradation were either confirmed or excluded by a variety of techniques such as addition of chelator EDTA and transitional metal ions or separation by ultrafiltration. RESULTS: This type of degradation was rarely reported in literature, especially considering its extreme cleavage efficiency. Contamination by a thermostable high molecular impurity (such as a peptidase with molecular weight between 10 and 30 KDa) during the manufacturing process was the main reason for this interesting phenomenon. CONCLUSIONS: The degradation phenomenon described here could be used as an excellent example showing that products ordered from vendors meeting the rudimentary quality standards might contain impurities which could cause significant degradation. We suggest that a simple solution, i.e. additional tests of stability under real or accelerated conditions by manufacturers and inclusion of the "accelerated stability criteria" in the Certificate of Analysis (CoAs), especially for sensitive biological reagents prone to faster degradation, would be very helpful for avoiding losses for both vendors and users.
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Glucagon/química , Quelantes/química , Cromatografia Líquida de Alta Pressão , Contaminação de Medicamentos , Estabilidade de Medicamentos , Ácido Edético/química , Concentração de Íons de Hidrogênio , Hidrólise , Peptídeo Hidrolases/química , Estabilidade Proteica , Espectrometria de Massas em Tandem , Elementos de Transição/química , UltrafiltraçãoRESUMO
Kappa (κ) opioid receptor selective antagonists are useful pharmacological tools in studying κ opioid receptors and have potential to be used as therapeutic agents for the treatment of a variety of diseases including mood disorders and drug addiction. Arodyn (Ac[Phe1-3,Arg4,d-Ala8]Dyn A-(1-11)NH2) is a linear acetylated dynorphin A (Dyn A) analog that is a potent and selective κ opioid receptor antagonist (Bennett et al. J Med Chem 2002;45:5617-5619) and prevents stress-induced reinstatement of cocaine-seeking behavior following central administration (Carey et al. Eur J Pharmacol 2007;569:84-89). To restrict its conformational mobility, explore possible bioactive conformations and potentially increase its metabolic stability we synthesized cyclic arodyn analogs on solid phase utilizing a novel ring-closing metathesis (RCM) reaction involving allyl-protected Tyr (Tyr(All)) residues. This approach preserves the aromatic functionality and directly constrains the side chains of one or more of the Phe residues. The novel cyclic arodyn analog 4 cyclized between Tyr(All) residues incorporated in positions 2 and 3 exhibited potent κ opioid receptor antagonism in the [35S]GTPγS assay (KBâ¯=â¯3.2â¯nM) similar to arodyn. Analog 3 cyclized between Tyr(All) residues in positions 1 and 2 also exhibited nanomolar κ opioid receptor antagonist potency (KBâ¯=â¯27.5â¯nM) in this assay. These are the first opioid peptides cyclized via RCM involving aromatic residues, and given their promising pharmacological activity represent novel lead peptides for further exploration.
Assuntos
Analgésicos Opioides/síntese química , Desenho de Fármacos , Dinorfinas/química , Tirosina/química , Sequência de Aminoácidos , Analgésicos Opioides/química , Analgésicos Opioides/metabolismo , Animais , Células CHO , Cricetinae , Cricetulus , Ciclização , Dinorfinas/síntese química , Dinorfinas/metabolismo , Ligação Proteica , Receptores Opioides kappa/antagonistas & inibidores , Receptores Opioides kappa/metabolismo , Relação Estrutura-AtividadeRESUMO
Nutritional awareness is described as having knowledge or understanding of nutrition. It is often related to the ability of an individual to make an accurate estimate of their food intake, which involves comparing their actual nutritional behavior with the recommended food consumption. Nutritional awareness of women during the various phases of pregnancy may vary significantly across countries due to cultural and lifestyle differences. There has been extensive research on nutritional awareness of pregnant women in selected countries or regions; however, relatively few studies have explored it during different stages of pregnancy. To fill this gap, this article reviews the existing literature and draws together insights into the following areas: changes in nutritional awareness during various phases of pregnancy, nutritional awareness of pregnant women and its underlying factors in various nations, and the research methods used to study nutritional awareness of pregnant women.
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Estado Nutricional , Gestantes , Feminino , Gravidez , Humanos , Comportamentos Relacionados com a Saúde , Projetos de PesquisaRESUMO
Goal: As an essential human-machine interactive task, emotion recognition has become an emerging area over the decades. Although previous attempts to classify emotions have achieved high performance, several challenges remain open: 1) How to effectively recognize emotions using different modalities remains challenging. 2) Due to the increasing amount of computing power required for deep learning, how to provide real-time detection and improve the robustness of deep neural networks is important. Method: In this paper, we propose a deep learning-based multimodal emotion recognition (MER) called Deep-Emotion, which can adaptively integrate the most discriminating features from facial expressions, speech, and electroencephalogram (EEG) to improve the performance of the MER. Specifically, the proposed Deep-Emotion framework consists of three branches, i.e., the facial branch, speech branch, and EEG branch. Correspondingly, the facial branch uses the improved GhostNet neural network proposed in this paper for feature extraction, which effectively alleviates the overfitting phenomenon in the training process and improves the classification accuracy compared with the original GhostNet network. For work on the speech branch, this paper proposes a lightweight fully convolutional neural network (LFCNN) for the efficient extraction of speech emotion features. Regarding the study of EEG branches, we proposed a tree-like LSTM (tLSTM) model capable of fusing multi-stage features for EEG emotion feature extraction. Finally, we adopted the strategy of decision-level fusion to integrate the recognition results of the above three modes, resulting in more comprehensive and accurate performance. Result and Conclusions: Extensive experiments on the CK+, EMO-DB, and MAHNOB-HCI datasets have demonstrated the advanced nature of the Deep-Emotion method proposed in this paper, as well as the feasibility and superiority of the MER approach.
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Adequate stabilization is essential for marketed protein-based biopharmaceutical formulations to withstand the various stresses that can be exerted during the pre- and post-manufacturing processes. Therefore, a suitable choice of excipient is a significant step in the manufacturing of such delicate products. Histidine, an essential amino acid, has been extensively used in protein-based biopharmaceutical formulations. The physicochemical properties of histidine are unique among amino acids and could afford multifaceted benefits to protein-based biopharmaceutical formulations. With a pKa of approximately 6.0 at the side chain, histidine has been primarily used as a buffering agent, especially for pH 5.5-6.5. Additionally, histidine exhibited several affirmative properties similar to those of carbohydrates (e.g., sucrose and trehalose) and could therefore be considered to be an alternative approach to established protein-based formulation strategies. The current review describes the general physicochemical properties of histidine, lists all commercial histidine-containing protein-based biopharmaceutical products, and discusses a brief outline of the existing research focused on the versatile applications of histidine, which can act as a buffering agent, stabilizer, cryo-/lyo-protectant, antioxidant, viscosity reducer, and solubilizing agent. The interaction between histidine and proteins in protein-based biopharmaceutical formulations, such as the Donnan effect during diafiltration of monoclonal antibody solutions and the degradation of polysorbates in histidine buffer, has also been discussed. As the first review of histidine in protein biopharmaceuticals, it helps to deepen our understanding of the opportunities and challenges associated with histidine as an excipient for protein-based biopharmaceutical formulations.
Assuntos
Excipientes , Histidina , Proteínas , Excipientes/química , Histidina/química , Proteínas/química , Composição de Medicamentos/métodos , Química Farmacêutica/métodos , Produtos Biológicos/química , Humanos , Estabilidade de MedicamentosRESUMO
The construction of heterojunctions can reduce the energy barrier for the oxygen evolution reaction (OER), which is crucial for the design of efficient electrocatalysts. A novel OER electrocatalyst, composed of g-C3N4-supported NiFeP spherical nanoclusters, was successfully synthesized using a simple hydrothermal method and a gas-phase precipitation method. Benefiting from its unique spherical nanocluster structure and strong electronic interactions among Ni, Fe, and P, the catalyst exhibited outstanding performance under alkaline conditions, with an overpotential of only 232â¯mV at a current density of 10â¯mAâ¯cm-2 and a Tafel slope of 103â¯mV dec-1. Additionally, the electrical resistance of NiFeP/g-C3N4 (Rctâ¯=â¯5.1â¯Ω) was much lower than that of NiFeP (Rctâ¯=â¯10.8â¯Ω) and layered g-C3N4 (Rctâ¯=â¯44.8â¯Ω). The formation of a Schottky barrier heterojunction efficiently reduced electron transfer impedance during the OER process, accelerating the electron transfer from g-C3N4 to NiFeP, enhancing the carrier concentration, and thereby improving the OER activity. Moreover, The robust g-C3N4 chain-mail protects NiFeP from adverse reaction environments, maintaining a balance between catalytic activity and stability. Furthermore, ab initio molecular dynamics (AIMD) and density functional theory (DFT) were conducted to explore the thermal stability and internal electron transfer behavior of the cluster heterojunction structure. This study offers a broader design strategy for the development of transition metal phosphide (TMPs) materials in the oxygen evolution reaction.
RESUMO
The search for highly efficient and inexpensive electrocatalysts is crucial to the advancement of environmentally friendly and sustainable energy sources. Here, adopting a one-step hydrothermal method, we have effectively fabricated a self-supported multi-metal molybdenum-based oxide (FeCoNi-MoO4) on nickel foam (NF). In addition to changing the catalyst's microstructure, the introducing of Fe and Co, enhanced its active center count, improved its electronic structure, and in turn reduced the difficulty for high-valence Ni and Fe species to form, which accelerates the oxygen evolution reaction (OER) kinetics by promoting the development of the actual active materials, NiOOH and FeOOH. FeCoNi-MoO4 has outstanding OER performance, requiring just 204 mV overpotentials at 10 mA cm-2 and 271 mV at 100 mA cm-2. Its exceptional OER kinetics at both low and high currents are indicated by a Tafel slope of 50.6 mV dec-1, which is attributed to the combined effect of its multi-metal composition and a higher number of active sites. Moreover, the FeCoNi-MoO4 electrode was operated continuously for over 48 h. Furthermore, the density functional theory (DFT) results demonstrated that the introducing of Fe and Co, which quickens the rate of electron transfer during the electrocatalytic process, improves the ability of oxygen intermediate species to adsorb, and ultimately lowers the overpotential, is responsible for the increased electrocatalytic activity of FeCoNi-MoO4. This work offers hope for further developments in the sector by proposing an efficient approach for creating multi-active electrocatalysts that are stable, economical, and efficient.
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We report the first atomistic simulation study to characterize poly(ionic liquid) (PIL) membranes and examine their capability for post-combustion CO(2) capture. Four PILs based on 1-vinyl-3-butylimidazolium ([VBIM](+)) are examined with four different anions, namely bis(trifluoromethylsulfonyl)imide ([TF(2)N](-)), thiocyanate ([SCN](-)), hexafluorophosphate ([PF(6)](-)) and chloride ([Cl](-)). Gas molecules (CO(2) and N(2)) in [VBIM](+)-based PILs interact with polycations more strongly than with anions. Therefore, the role of anions in gas solubility is insignificant, which is in remarkable contrast to monomeric ILs. The solubilities predicted in the four PILs are close and in good agreement with available experimental data. The sorption, diffusion and permeation selectivities of CO(2)/N(2) predicted from simulation are consistent with experiment. Particularly, the diffusion selectivities are approximately equal to one, implying that CO(2)/N(2) separation is governed by sorption. This study provides atomistic insight into the mechanisms of gas sorption, diffusion and permeation in [VBIM](+)-based PILs and reveals that polycations play a dominant role in determining gas-membrane interaction and separation.
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Nucleic acid (NA)-based biopharmaceuticals have emerged as promising therapeutic modalities. NA therapeutics are a diverse class of RNA and DNA and include antisense oligonucleotides, siRNA, miRNA, mRNA, small activating RNA, and gene therapies. Meanwhile, NA therapeutics have posed significant stability and delivery challenges and are expensive. This article discusses the challenges and opportunities for achieving stable formulations of NAs with novel drug delivery systems (DDSs). Here we review the current progress in the stability issues and the significance of novel DDSs associated with NA-based biopharmaceuticals, as well as mRNA vaccines. We also highlight the European Medicines Agency (EMA) and US Food and Drug Administration (FDA)-approved NA-based therapeutics with their formulation profiles. NA therapeutics could impact future markets if the remaining challenges and requirements are addressed. Regardless of the limited information available for NA therapeutics, reviewing and collating the relevant facts and figures generates a precious resource for formulation experts familiar with the NA therapeutics' stability profile, their delivery challenges, and regulatory acceptance.