Investigating the Influence of Polysorbate 20/80 and Polaxomer P188 on the Surface & Interfacial Properties of Bovine Serum Albumin and Lysozyme

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.'

Comparison of Protein Particle Formation in IgG1 mAbs Formulated with PS20 Vs. PS80 When Subjected to Interfacial Dilatational Stress

Polysorbates (PS) are nonionic surfactants that are commonly included in protein formulations to mitigate the formation of interfacial stress-induced protein particles and thus increase their long-term storage stability. Nonetheless, factors that dictate the efficiency of different polysorbates in mitigating protein particle formation, especially during the application of interfacial stresses, are often ill defined. Here, we used a Langmuir trough to determine the surface activity of two IgG1 monoclonal antibodies formulated with two different polysorbates (PS20 and PS80) when subjected to interfacial dilatational stress. Interfacial properties of these formulations were then correlated with characterization of subvisible protein particles measured by micro-flow imaging (MFI). Both mAbs, when formulated in PS20, demonstrate faster adsorption kinetics and higher surface activity compared to PS80 or surfactant-free formulations. Compression/expansion results suggest that when exposed to interfacial dilatational stresses, both mAb/PS20 formulations display interfacial properties of PS20 alone. In contrast, interfacial properties of both mAb/PS80 formulations suggest mAbs and PS80 are co-adsorbed to the air-water interface. Further, MFI analysis of the interface and the bulk solution confirms that PS20 is more effective than PS80 at mitigating the formation of larger particles in the bulk solution in both mAbs. Concomitantly, the efficiency of PS to prevent interface-induced protein particle formation also depended on the protein's inherent tendency to aggregate at a surfactant-free interface. Together, the studies presented here highlight the importance of determining the interfacial properties of mAbs, surfactants, and their combinations to make informed formulation decisions about the choice of surfactant.

In-vial printing and drying of biologics as a personalizable approach

This study addressed the need for a flexible (personalizable) production of biologics, allowing their stabilization in the solid state and processing of small batch volumes. Therefore, inkjet printing into vials followed by a gentle vacuum drying step at ambient temperature was investigated by screening different formulations with a 2²-full factorial design of experiments regarding printability. Human Serum Albumin (HSA) was used as a model protein in a wide range of concentrations (5 to 50 mg/ml), with (10 w/v%) and without the surfactant polysorbate 80 (PS80). PS80 was identified to positively affect the formulations by increasing the Ohnesorge number and stabilizing the printing process. The dispensed volumes with a target dose of 0.5 mg HSA were dried and analyzed concerning their residual moisture (RM) and protein aggregation. All investigated formulations showed an RM < 10 wt% and no significant induced protein aggregation as confirmed by Size Exclusion Chromatography (<2.5%) and Dynamic Light Scattering (Aggregation Index ≤ 2.5). Additionally, long-term printability and the available final dose after reconstitution were investigated for two optimized formulations. A promising formulation providing ∼93% of the targeted dose and a reconstitution time of 30 s was identified.

The Amphoteric Surfactant N,N-Dimethyldodecylamine N-Oxide Unfolds β-Lactoglobulin above the Critical Micelle Concentration

Understanding the interactions between surfactants and proteins is important for the formulation of consumer products as surfactant binding can alter protein activity and stability. Additionally, the structure of the protein-surfactant complex can influence surface activity, which is important for emulsion and foam development. N,N-Dimethyldodecylamine N-oxide (DDAO) is an amphoteric surfactant that is nonionic at high pH. It is often used as a foam booster in detergent formulations and for the extraction of membrane proteins. In this study, a variety of biophysical characterization methods was used to investigate the impact of DDAO at pH 8 on the structure of the globular protein β-lactoglobulin (βLG). Pyrene fluorescence and surface tension studies show that βLG had minimal impact on the critical micelle concentration (CMC) of DDAO, while fluorescence and circular dichroism spectroscopy found unfolding of βLG at concentrations of DDAO greater than the CMC. Small-angle X-ray scattering results confirm changes in the structure of βLG at DDAO concentrations above the CMC. Taken together, DDAO behaves like nonionic and zwitterionic surfactants below its CMC with limited interaction with βLG, while it induces protein unfolding at concentrations higher than the CMC, resulting in a protein-surfactant complex structure that resembles a protein-decorated micelle.

Polysorbate Degradation and Particle Formation in a High Concentration mAb: Formulation Strategies to Minimize Effect of Enzymatic Polysorbate Degradation

Polysorbate (PS) 20 and 80 are the most common surfactants in monoclonal antibody (mAb) drug product (DP) formulations. Residual host cell proteins (HCP) present at extremely low concentrations in DP formulations can maintain enough enzymatic activity to degrade PS surfactants. Over time, the hydrolysis of surfactant causes the accumulation of minimally soluble free fatty acids resulting in precipitation and formation of subvisible and visible particulates. This manuscript summarizes the investigation of a batch of high concentration (>100 mg/mL) mAb DP where subvisible particles formed abruptly after prolonged storage at 5C°. The work also summarizes the effectiveness of different strategies for managing host cell proteins and fatty acid particles. The concentration and fatty acid composition of polysorbates were found to be significant factors in particle development. Solubilizers and alternative surfactants were all shown to be effective means of preventing particle formation. Lipase inhibitors proved to be a simple means to identify the problem but are more difficult to utilize as a solution.

Challenges and effective routes for formulating and delivery of epidermal growth factors in skin care

Epidermal growth factors are important morphogenetic proteins that instruct cell behaviour. They have many inferred applications within regenerative medicine and have shown promising results in skincare treatments. Many growth factors are known to have skin anti-ageing benefits along with further potential in resolving scarring, acne and other skin disorders. Incorporation of these biologics into skincare formulations has been greatly hindered by low transdermal delivery efficacy, intricate material interactions and protein instability - especially within common cosmetic emulsions. This review explores the cosmeceutical capability of growth factors in skin care, current understandings of constituent interactions and advantageous delivery approaches for more effective topical delivery. The first section highlights the influences growth factor product formulation has on stability and synergy. Current understandings of growth factor formulating techniques in cosmetic products is limited, and the performance of other protein structures is an adequate point of reference. The second section examines emerging drug delivery systems to overcome the challenges of topical growth factor treatment. It is important to consider the coaction and durability of all components in a formulation simultaneously: active ingredients, product format and delivery vehicle, in order to engineer an optimal cosmeceutical product.

Optimizing interactions between soluble silk fibroin and capryl glucoside for design of a natural and high-performance co-surfactant system

OBJECTIVES

Because of the strong consumer driver towards more natural or higher sustainability cosmetic products, silk fibroin was evaluated to help develop a formulation with natural and effective ingredients for personal care. In order to exploit the physical properties of silk fibroin, it was evaluated to maximize the surfactant properties of other commercial ingredients to lower surface tension and build up viscosity. A synergistic effect was seen between silk fibroin and capryl glucoside, a sugar surfactant which exhibited a natural and effective co-surfactant system. This system demonstrated better surface tension properties than sodium laureth sulphate (SLES), cocamidopropyl betaine (CAPB), rhamnolipids and sophorolipids, which led to greater foamability and cleansing properties. This system proved to also be compatible with polysaccharide viscosity modifiers to enhance the viscosity of the system. The present study comprises a systematic exploration of natural formulation development of silk proteins and other natural ingredients, which result in high performance such as enhanced foam quality, foam stability and enhanced sebum removal. All of these properties are desirable and may utilized when formulating cleaners and shampoos.

METHODS

A force tensiometer, Attension Sigma 701, was used to measure the surface tension of the silk protein and its various combinations with biosurfactants and biopolymers. To measure bulk rheology, a traditional mechanical rheometer TA DHR-3 was utilized. Foaming tests and sebum removal assays were also carried out to evaluate the performance of the samples.

RESULTS

Silk fibroin was evaluated to maximize the surfactant properties of other commercial systems to develop a formulation containing natural and effective ingredients for personal care. The surface activity of silk proteins was seen to be synergistically enhanced in the presence of sugar surfactants such as capryl glucoside, resulting in a surface tension at the air-water interface which is lower than either that of pure silk fibroin or pure capryl glucoside. This surface tension value is additionally lower than that obtained from currently utilized synthetic surfactants like sodium laureth sulphate (SLES) and cocamidopropyl betaine (CAPB). This reduction in surface tension demonstrated greater foamability and cleansing properties than that of the commercial systems. The very low surface tension values obtained through combinations of silk proteins and glucoside resulted in a natural and effective co-surfactant system by forming high-quality stable foams and enhancing sebum removal. The rheological performance of the silk proteins was impacted through microstructure modifications as a result of interactions with biopolymers like carrageenan. This shows that this system is compatible with polysaccharide viscosity modifiers. It was observed that both the flow curve and the absolute viscosity values were significantly impacted in the presence of carrageenan, with higher viscosity generation and significant non-Newtonian/shear thinning behaviour evolution. These results indicate that the silk fibroin can be utilized to build a high-performance natural product and significantly enhance the performance of other natural/sustainable cosmetic formulations through building synergistic interactions with other natural ingredients such as sugar surfactants and biopolymers. These properties exhibited by this system are all desirable for cleansers and shampoos within the cosmetic industry.

CONCLUSION

Silk fibroin in combination with capryl glucoside outperforms other commercial surfactants that are commonly used in the industry because of its surface-active behaviour and synergy. This system is then enhanced further with polysaccharide rheological modifiers, carrageen and xanthan gum to help build up viscosity. The complex mixture of silk fibroin, sugar surfactant and biopolymer results in a formulation that is all natural, while still having high performance by achieving great foamability and enhanced sebum removal. The mixture can further be used to formulate a fully natural product such as a cleanser or shampoo while still having the same or greater effectiveness as synthetic surfactants and ingredients typically used in cosmetic formulations.

Stability of Biologics and the Quest for Polysorbate Alternatives

Most biopharmaceutical formulations use polysorbates: surfactants that are highly efficient but difficult to manage in terms of compositional variability, quality, and stability. Alternatives, such as poloxamers, albumin, and cyclodextrin, are becoming popular and are being explored for their potential to protect biopharmaceuticals against physical and mechanical stresses.

Damage of proteins at the air/water interface: Surface tension characterizes globulin interface stability

In the present study, we aimed to see what circumstances may cause protein damage at air/water interface and reveal the correlation between the surface properties of protein solution and the interface stability. The surface hydrophobicity and β-sheet of protein were determined by exogenous fluorescent probes, and the changes in the spatial structure of proteins were characterized by steady-state fluorescence spectroscopy. The surface tension was determined by the plate method, and such value was used to establish the correlation with the hydrophobicity and structure of the protein. Moreover, degree of aggregation in the presence or absence of Hofmeister salt in protein solution was investigated. There was a significant correlation between the surface tension and hydrophobicity of the protein solution (P < 0.05). The surface tension and structure of the protein also showed a significant correlation under the induction of pH (P < 0.05). Furthermore, when the protein was induced by the air/water interface, the surface tension, hydrophobicity, and structure of proteins were correlated, and protein aggregation was increased. When the additive induced a decrease in the surface tension of the protein solution, the protein aggregation was promoted. These findings provided valuable insights into the relationship between surface tension of the protein solution and interfacial stability and paved the way for future pre-formulation studies of therapeutic proteins.

Oxidative stress-induced cardiomyocyte apoptosis is associated with dysregulated Akt/p53 signaling pathway

Oxidative stress may play a crucial role in cardiac and vascular abnormalities in different types of cardiovascular diseases. In the present study, we explored the mechanism underlying oxidative stress-mediated cardiomyocyte apoptosis with a focus on the Akt-p53 signaling pathway. In vitro, cardiomyocyte was cultured with different concentrations of hydrogen peroxide. Then, cardiomyocyte viability, apoptosis rate and signaling pathway were analyzed through ELISA, immunofluorescence, qPCR and western blots. The results indicated that oxidative stress caused cardiomyocyte apoptosis in a dose-dependent manner. Mechanistically, oxidative stress inhibited cardiomyocyte glucose metabolism and promoted lactic acid accumulation. Besides, oxidative stress triggered calcium overload in cardiomyocyte. Finally, we found that oxidative stress inhibited the activity of Akt pathway while activated p53 signaling pathway. Genetic knockdown of p53 abolished oxidative stress-mediated cardiomyocyte injury and death through regulating the expressions and activities of caspase-3 and Bax. Altogether, our results illustrate that oxidative stress is associated with cardiomyocyte apoptosis through a mechanism involving dysregulated Akt/p53 signaling pathway.

Melatonin improves mitochondrial biogenesis through the AMPK/PGC1α pathway to attenuate ischemia/reperfusion-induced myocardial damage

Cardiac ischemia/reperfusion injury is associated with reduced mitochondrial turnover and regeneration. There is currently no effective approach to stimulate mitochondrial biogenesis in the reperfused myocardium. In this study, we investigated whether melatonin could increase mitochondrial biogenesis and thus promote mitochondrial homeostasis in cardiomyocytes. Cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) injury with or without melatonin treatment, and various mitochondrial functions were measured. H/R injury repressed mitochondrial biogenesis in cardiomyocytes, whereas melatonin treatment restored mitochondrial biogenesis through the 5’ adenosine monophosphate-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC1α) pathway. Melatonin enhanced mitochondrial metabolism, inhibited mitochondrial oxidative stress, induced mitochondrial fusion and prevented mitochondrial apoptosis in cardiomyocytes subjected to H/R injury. The melatonin-induced improvement in mitochondrial biogenesis was associated with increased cardiomyocyte survival during H/R injury. On the other hand, silencing of PGC1α attenuated the protective effects of melatonin on cardiomyocyte viability, thereby impairing mitochondrial bioenergetics, disrupting the mitochondrial morphology, and activating mitochondrial apoptosis. Thus, H/R injury suppressed mitochondrial biogenesis, while melatonin activated the AMPK/PGC1α pathway and restored mitochondrial biogenesis, ultimately protecting the reperfused heart.