Solid-state vibrational circular dichroism for pharmaceutical applications: Polymorphs and cocrystal of sofosbuvir.

X-ray diffraction is a commonly used technique in the pharmaceutical industry for the determination of the atomic and molecular structure of crystals. However, it is costly, sometimes time-consuming, and it requires a considerable degree of expertise. Vibrational circular dichroism (VCD) spectroscopy resolves these limitations, while also exhibiting substantial sensitivity to subtle modifications in the conformation and molecular packaging in the solid state. This study showcases VCD's ability to differentiate between various crystal structures of the same molecule (polymorphs, cocrystals). We examined the most effective approach for producing high-quality spectra and unveiled the intricate link between structure and spectrum via quantum-chemical computations. We rigorously assessed, using alanine as a model compound, multiple experimental conditions on the resulting VCD spectra, with the aim of proposing an optimal and efficient procedure. The proposed approach, which yields reliable, reproducible, and artifact-free results with maximal signal-to-noise ratio, was then validated using a set comprising of three amino acids (serine, alanine, tyrosine), one hydroxy acid (tartaric acid), and a monosaccharide (ribose) to mimic active pharmaceutical components. Finally, the optimized approach was applied to distinguish three polymorphs of the antiviral drug sofosbuvir and its cocrystal with piperazine. Our results indicate that solid-state VCD is a prompt, cost-effective, and easy-to-use technique to identify crystal structures, demonstrating potential for application in pharmaceuticals. We also adapted the cluster and transfer approach to calculate the spectral properties of molecules in a periodic crystal environment. Our findings demonstrate that this approach reliably produces solid-state VCD spectra of model compounds. Although for large molecules with many atoms per unit cell, such as sofosbuvir, this approach has to be simplified and provides only a qualitative match, spectral calculations, and energy analysis helped us to decipher the observed differences in the experimental spectra of sofosbuvir.

The impact of polymer mixture composition on the properties of electrospun membranes for drug delivery applications.

Orally dispersible films (ODFs) prepared by an electrospinning are a novel type of pharmaceutical formulation. This dosage form has the potential to be beneficial for small children and the elderly, who can have problems with administration of classical tablets due to the increased risk of choking and difficulty with swallowing. Due to the highly porous nanofiber morphology, the ODFs examined in this study achieve rapid disintegration into drug microparticles when in contact with saliva. The suspension is then easier to swallow. In this study, we focus on the impact of film composition (polymer matrix composition) on the properties of electrospun membranes. In particular, we prepared ODFs composed of a mixture of PEG 100 000 with HPMC E5 and PVP k90 with HPMC E5. We found significant differences in the structure of electrospinned membranes, where samples containing PEG 100 000 and HPMC E5 exhibited much narrower distribution of fibers. Furthermore, nanofibers containing PVP k90 exhibit a faster disintegration rate, while dissolution of the drug was faster in the case of PEG 100 000 containing ODFs. The improvement was caused by both the structure and composition of the membranes.

Efficient full solar spectrum-driven photocatalytic hydrogen production on low bandgap TiO2/conjugated polymer nanostructures.

The development of photocatalysts that can utilize the entire solar spectrum is crucial to achieving efficient solar energy conversion. The utility of the benchmark photocatalyst, TiO2, is limited only to the UV region due to its large bandgap. Extending the light harvesting properties across the entire spectrum is paramount to enhancing solar photocatalytic performance. In this work, we developed low bandgap TiO2/conjugated polymer nanostructures which exhibit full spectrum activity for efficient H2 production. The highly mesoporous structure of the nanostructures together with the photosensitizing properties of the conjugated polymer enabled efficient solar light activity. The mesoporous TiO2 nanostructures calcined at 550 °C exhibited a defect-free anatase crystalline phase with traces of brookite and high surface area, resulting in the best performance in hydrogen production (5.34 mmol g-1 h-1) under sunlight simulation. This value is higher not only in comparison to other TiO2-based catalysts but also to other semiconductor materials reported in the literature. Thus, this work provides an effective strategy for the construction of full spectrum active nanostructured catalysts for enhanced solar photocatalytic hydrogen production.

Herbal concoction Unveiled: A computational analysis of phytochemicals' pharmacokinetic and toxicological profiles using novel approach methodologies (NAMs).

Herbal medications have an extensive history of use in treating various diseases, attributed to their perceived efficacy and safety. Traditional medicine practitioners and contemporary healthcare providers have shown particular interest in herbal syrups, especially for respiratory illnesses associated with the SARS-CoV-2 virus. However, the current understanding of the pharmacokinetic and toxicological properties of phytochemicals in these herbal mixtures is limited. This study presents a comprehensive computational analysis utilizing novel approach methodologies (NAMs) to investigate the pharmacokinetic and toxicological profiles of phytochemicals in herbal syrup, leveraging in-silico techniques and prediction tools such as PubChem, SwissADME, and Molsoft's database. Although molecular dynamics, docking, and broader system-wide analyses were not considered, future studies hold potential for further investigation in these areas. By combining drug-likeness with molecular simulation, researchers identify diverse phytochemicals suitable for complex medication development examining their pharmacokinetic-toxicological profiles in phytopharmaceutical syrup. The study focuses on herbal solutions for respiratory infections, with the goal of adding to the pool of all-natural treatments for such ailments. This research has the potential to revolutionize environmental and alternative medicine by leveraging in-silico models and innovative analytical techniques to identify novel phytochemicals with enhanced therapeutic benefits and explore network-based and systems biology approaches for a deeper understanding of their interactions with biological systems. Overall, our study offers valuable insights into the computational analysis of the pharmacokinetic and toxicological profiles of herbal concoction. This paves the way for advancements in environmental and alternative medicine. However, we acknowledge the need for future studies to address the aforementioned topics that were not adequately covered in this research.

3D Raman mapping as an analytical tool for investigating the coatings of coated drug particles.

The properties of dry-coated paracetamol particles (fast-dissolving model drug) with carnauba wax particles as the coating agent (dissolution retardant) were investigated. Raman mapping technique was used to non-destructively examine the thickness and homogeneity of coated particles. The results showed that the wax existed in two forms on the surface of the paracetamol particles, forming a porous coating layer: i) whole wax particles on the surface of paracetamol and glued together with other wax surface particles, and ii) deformed wax particles spread on the surface. Regardless of the final particle size fraction (between 100 and 800 µm), the coating thickness had high variability, with average thickness of 5.9 ± 4.2 µm. The ability of carnauba wax to decrease the dissolution rate of paracetamol was confirmed by dissolution of powder and tablet formulations. The dissolution was slower for larger coated particles. Tableting further reduced the dissolution rate, clearly indicating the impact of subsequent formulation processes on the final quality of the product.

Formation of ibrutinib solvates: so similar, yet so different.

The transformation processes of non-solvated ibrutinib into a series of halogenated benzene solvates are explored in detail here. The transformation was studied in real time by X-ray powder diffraction in a glass capillary. Crystal structures of chlorobenzene, bromobenzene and iodobenzene solvates are isostructural, whereas the structure of fluorobenzene solvate is different. Four different mechanisms for transformation were discovered despite the similarity in the chemical nature of the solvents and crystal structures of the solvates formed. These mechanisms include direct transformations and transformations with either a crystalline or an amorphous intermediate phase. The binding preference of each solvate in the crystal structure of the solvates was examined in competitive slurry experiments and further confirmed by interaction strength calculations. Overall, the presented system and online X-ray powder diffraction measurement provide unique insights into the formation of solvates.

Computational fluid dynamics simulation improves the design and characterization of a plug-flow-type scale-down reactor for microbial cultivation processes.

The scale-up of bioprocesses remains one of the major obstacles in the biotechnology industry. Scale-down bioreactors have been identified as valuable tools to investigate the heterogeneities observed in large-scale tanks at the laboratory scale. Additionally, computational fluid dynamics (CFD) simulations can be used to gain information about fluid flow in tanks used for production. Here, we present the rational design and comprehensive characterization of a scale-down setup, in which a flexible and modular plug-flow reactor was connected to a stirred-tank bioreactor. With the help of CFD using the realizable k-ε model, the mixing time difference between a 20 and 4000 L bioreactor was evaluated and used as scale-down criterion. CFD simulations using a shear stress transport (SST) k-ω turbulence model were used to characterize the plug-flow reactor in more detail, and the model was verified using experiments. Additionally, the model was used to simulate conditions where experiments technically could not be performed due to sensor limitations. Nevertheless, verification is difficult in this case as well. This was the first time a scale-down setup was tested on high-cell-density Escherichia coli cultivations to produce industrially relevant antigen-binding fragments (Fab). Biomass yield was reduced by 11% and specific product yield was reduced by 20% during the scale-down cultivations. Additionally, the intracellular Fab fraction was increased by using the setup. The flexibility of the introduced scale-down setup in combination with CFD simulations makes it a valuable tool for investigating scale effects at the laboratory scale. More information about the large scale is still necessary to further refine the setup and to speed up bioprocess scale-up in the future.

Quality assessment of niosomal suspensions.

Niosomes are vesicular carriers formed by a bilayer shell, which is composed of non-ionic surfactants with the addition of a structural supporting agent. Cholesterol is typically used as an additive to increase the stability or drug entrapment efficiency of niosomes. Although increasing the amount of cholesterol is reported to improve niosomal properties, an excessive amount of cholesterol may not be accommodated in the bilayer shell, and thus remain in the crystalline form in the niosomal solution. The presence of a crystalline phase is a potential risk for further medical application. Therefore, Tween 80-based niosomes were prepared using a well-established thin-film hydration method and organic phase injection method, followed by their thorough characterization in order to estimate the cholesterol incorporation into the niosomal shell. To detect the crystalline phase in the niosomal suspensions, a novel approach based on depolarized dynamic light scattering combined with cryo-transmission electron microscopy, X-ray diffraction and optical microscopy is used to confirm the presence of cholesterol crystals. This method is fast, quantitative, and allows the sample analysis in a natural liquid environment, thus eliminating biased results influenced by sample drying.

Application of Oil-in-Water Cannabidiol Emulsion for the Treatment of Rheumatoid Arthritis.

Introduction: Rheumatoid arthritis (RA) is a chronic autoimmune disease with unknown cause. It mainly affects joints and, without proper treatment, negatively impacts their movement, causes painful deformities, and reduces the patients' quality of life. Current treatment options consist of various types of disease-modifying antirheumatic drugs (DMARDs), however 20-30% of patients are partially resistant to them. Therefore, development of new drugs is necessary. Possible option are compounds exhibiting their action via endocannabinoid system, which plays an important role in pain and inflammation modulation. One such compound - cannabidiol (CBD) has already been shown to attenuate synovitis in animal model of RA in in vivo studies. However, it has low bioavailability due to its low water solubility and lipophilicity. This issue can be addressed by preparation of a lipid containing formulation targeting lymphatic system, another route of absorption in the body. Materials and Methods: CBD-containing emulsion was prepared by high-shear homogenization and its droplet size distribution was analysed by optical microscopy. The relative oral bioavailability compared to oil solution as well as total availability of CBD were assessed in a cross-over study in rats and absorption of CBD via lymphatic system was observed. The effect of CBD on the animal model of RA was determined. Results: Compared to oil solution, the emulsion exhibited higher absolute oral bioavailability. Significant lymphatic transport of CBD was observed in all formulations and the concentrations in lymph were calculated. The therapeutic effect of CBD on RA was confirmed as an improvement in clinical symptoms as well as morphological signs of disease activity were observed during the study. Conclusion: In this work, we prepared a simple stable emulsion formulation, determined the pharmacokinetic parameters of CBD and calculated its absolute bioavailability in rats. Moreover, we successfully tested the pharmaceutical application of such a formulation and demonstrated the positive effect of CBD in an animal model of RA.

Pharmaceutical Product Characterization and Manufacturability of Surfactant-Enriched Oil Marbles with Abiraterone Acetate.

The present study investigates the physicochemical properties and stability of a novel lipid-based formulation-surfactant-enriched oil marbles containing abiraterone acetate. While the biopharmaceutical performance of this formulation has been reported recently, this study aims to fill the gap between a promising in vivo performance and industrial applicability. A series of techniques were employed to assess the solid-state characteristics of oil marble cores along with their physicochemical properties upon stability testing. The chemical stability of abiraterone acetate in the formulation was also investigated. The core of the formulation was found to be stable both physically and chemically over 12 months of storage. The in vitro performance of stressed samples was evaluated using a dissolution experiment. The formulation has successfully self-emulsified upon incubation in bio-relevant media, resulting in a fast and complete API release. An important issue connected with the excipient used as a covering material of oil marbles has been identified. The seemingly insignificant water sorption caused agglomeration of the oil marbles and consequently compromised the dissolution rate in some of the stressed samples. Replacing HPMC with lactose as a covering material resulted in more favorable properties upon storage. Overall, it has been shown that oil marbles are an industrially applicable concept of the solidified lipid-based formulation.

Structure-property relations of a unique and systematic dataset of 19 isostructural multicomponent apremilast forms.

The structure-property relations are examined for apremilast cocrystals and solvates in this work. A unique and large dataset of multicomponent crystal forms is presented including 7 cocrystals and 12 solvates. In total, 15 of the presented multicomponent forms and their crystal structures are published here for the first time. This dataset is unique owing to the extreme crystal packing similarity of all 19 crystal forms. This fact makes the evaluation of structure-property relations significantly easier and more precise since the differences in the crystal lattice arrangement are close to negligible. Properties of the guest molecules used here can be directly correlated with the macroscopic properties of the corresponding multicomponent forms. Interestingly, a considerable correlation was found between the intrinsic dissolution rate of the multicomponent forms and their solubility, as well as the solubility of their guest molecules in the dissolution medium. The latter is of particular interest as it can aid in the design of multicomponent forms with tuned properties.

Explaining dissolution properties of rivaroxaban cocrystals.

The aim of this study was to improve rivaroxaban water-solubility by cocrystal preparation and to understand this process. The screening with water-soluble coformers was performed via both mechanochemical and solution-mediated techniques. Two cocrystals of rivaroxaban with malonic acid and oxalic acid were prepared, and the structure of the cocrystal with oxalic acid was solved. Both cocrystals exhibit improved dissolution properties. The mechanism of the supersaturation maintenance was studied by in-situ Raman spectroscopy. The transformation into rivaroxaban dihydrate was identified as the critical step in the improved dissolution properties of both cocrystals. Moreover, the transformation kinetics and solubilization effects of the coformers were identified as responsible for the differences in the dissolution behavior of the cocrystals. In-vivo experiments proved that the use of cocrystal instead of form I of free API helped to increase the bioavailability ofrivaroxaban.

The impact of the lamination pressure on the properties of electrospinned nanofibrous films.

The purpose of this work is to explore the preparation of nanofibrous orally dispersible films (ODFs) by needleless electrospinning from the active pharmaceutical ingredient (API) Tadalafil using particles suspended in a solution of polymers and other excipients. The prepared films were characterized by a combination of scanning electron microscopy, mechanical tests, measurements of the disintegration time and dissolution characteristic, X-ray diffraction, and differential scanning calorimetry. Furthermore, we investigated the impact of lamination pressures in the range of 0 to 5 bars combined with films at various relative humidity values on the mechanical properties of the ODF. An increase in lamination pressure resulted in higher Young's modulus values, with the maximum value observed for a sample laminated at a pressure of 5 bar and the maximum stress and strain of the prepared ODF at a lamination pressure of 1.2 bar. Moreover, there was a significant increase in the disintegration time with increase in lamination pressure. The disintegration time ranged from 0.35 s for non-laminated samples to 12 s for samples laminated at a pressure of 5 bar. On the contrary, the lamination pressure did not reveal to have any impact on the dissolution kinetics. These results confirmed that the lamination pressure can improve the processability of ODFs without affecting the API dissolution kinetics.

Impact of Solvent-Drug Interactions on the Desolvation of a Pharmaceutical Solvate.

In drug manufacturing, solvent-based methods are used for the crystallization of active pharmaceutical ingredients (APIs). Often, the solvent interacts with the API resulting in the formation of a new solid compound, the solvate. When desolvation occurs upon heating, it might result in the formation of new solid forms with significantly different physicochemical properties. Therefore, in this work, we study the desolvation kinetics by combining in situ powder X-ray diffraction (PXRD), all-atom molecular dynamics (MD) simulations, and macroscopic solid-state reaction kinetics modeling. The fluorobenzene (FB) solvate of Bruton's tyrosine kinase inhibitor Ibrutinib (IBR) was used as a model system. While the macroscopic solid-state modeling provides information about the desolvation kinetics, the MD simulations were used to trace individual FB molecules inside the crystal lattice. The activation energy of confined solvent diffusion, obtained by MD simulations, agrees well with results of the macroscopic solid-state reaction kinetics modeling. In addition, MD simulations provided detailed information about the IBR-FB interactions at the nanoscale. The mechanism revealed is that the solvent molecules diffusion, controlled by distinct open-close gating conformational changes of the drug, triggers the desolvation throughout the crystal lattice.

Monitoring of particle sizes distribution during Valsartan precipitation in the presence of nonionic surfactant.

Particle size is a key parameter when dealing with drug particle formation, delivery or dissolution. The correct measurement of particle size depends on various factors, such as sample preparation or dilution, but also on the choice of method for its characterization. In this work, we study the process of precipitation of poorly water-soluble drug Valsartan from supersaturated solution in the presence of nonionic surfactant Tween 20. Several techniques including dynamic light scattering (DLS) operated in several measuring modes, optical microscope (OM) and static light scattering (SLS) were used to analyze the kinetics of particle formation. As concluded by the results, the increase in turbidity of the solution seriously limits the application of classical DLS to properly measure the particle size and polydispersity. One way to get around this restriction is by dilution, which however results in a decrease in the size of Valsartan particles in the studied population. In contrast, here we present for a first time technique based on modulated 3D cross correlation DLS equipped with the sample goniometer to determine size of submicron particles of the drug in highly turbid solutions. Additionally, a modified OM was used to measure micron-sized particles for samples without any dilution in a continuous mode. Measured particle sizes combined with measured Valsartan concentration allowed us to identify mechanism responsible for the particle formation from supersaturated solutions. The main mechanism, as it is shown in this work, is covering surface of precipitate particles by the amount of used Tween 20.

Morphology of Shear-Induced Colloidal Aggregates in Porous Media: Consequences for Transport, Deposition, and Re-entrainment.

Colloid deposition in granular media is relevant to numerous environmental problems. Classic filtration models assume a homogeneous pore space and largely ignore colloid aggregation. However, substantial evidence exists on the ubiquity of aggregation within porous media, suggesting that deposition is enhanced by it. This work studies the deposition process in relation to aggregate size and structure. We demonstrate that aggregation is induced at typical groundwater velocities by comparing the repulsive DLVO force between particle pairs to the hydrodynamic shear force opposing it. Column experiments imaged with high-resolution X-ray computed tomography are used to measure aggregate structure and describe their morphology probability distribution and spatial distribution. Aggregate volume and surface area are found to be power-law distributed, while Feret diameter is exponentially distributed with some flow rate dependencies caused by erosion and restructuring by the fluid shear. Furthermore, size and shape of aggregates are heterogeneous in depth, where a small number of large aggregates control the concentration versus depth profile shape. The range of aggregate fractal dimensions found (2.22-2.42) implies a high potential for restructuring or breaking during transport. Shear-induced aggregation is not currently considered in macroscopic models for particle filtration, yet is critical to consider in the processes that control deposition.

Numerical Modeling of Viscoelasticity in Particle Suspensions Using the Discrete Element Method.

The rheological behavior of particle suspensions is a challenging problem because its description depends on the interaction of two phases with different material properties. This interaction can lead to complex behavior because of acting forces at the solid-liquid interface such as lubrication. The goal of this work is to propose a method for the modeling of fluids viscoelasticity in the presence of spherical particles including fluid-particle interactions. To accomplish this, we employed a simplified approach using the discrete element method (DEM) coupled with computational fluid dynamics (CFD) to simulate a suspension of particles under oscillatory flow in a three-dimensional computational domain. The choice of DEM provides versatility to customize the constitutive relations of particle-particle and fluid-particle interactions. Particularly, we focused on studying the effect of solid-liquid interaction (lubrication forces) on the viscoelasticity of the particulate system. To analyze the effect of this interfacial force, we simplified the particle-particle interaction to a nonadhesive elastic contact, thus avoiding aggregation of the particles. The work consists of two parts: the first one is a pure CFD model of the oscillatory motion applied to a Newtonian fluid (without particles), and the second is an extended version including DEM to simulate the viscoelasticity of the particle suspension. In this way, we can isolate the effect of fluid inertia on the viscoelasticity of the particulate system. The obtained results show that the model is capable to reproduce qualitatively the increase of the storage modulus as a function of the solid volume fraction and the dependence of dynamic moduli on the applied shear strain. The presented methodology provides a new insight into modeling of rheology by customizing interactions at the particle level based purely on first-principles with model parameters including solely material properties and physically identifiable quantities.

Complex methodology for rational design of Apremilast-benzoic acid co-crystallization process.

A new co-crystal of pharmaceutical active ingredient Apremilast was successfully designed in this work. The discovered co-crystal with benzoic acid significantly improves key properties like the dissolution and stability of an otherwise poorly soluble Apremilast. A crystallization process was developed, which includes efficient solvent selection and ternary phase diagram construction to minimize risks during scale up. To increase efficiency, we propose that both steps be combined into a single methodology based on solubility data. A suitable solvent for the co-crystallization process was selected and ternary phase diagrams were constructed using three different modifications of thermodynamic model of solid-liquid equilibria. Based on the obtained information, the co-crystallization process was scaled-up to 100 mL. This provides a feasible process to produce larger amounts of this promising pharmaceutical solid form of Apremilast necessary for further drug development.

Transcriptome and proteome analysis of steady-state in a perfusion CHO cell culture process.

Long-term continuous protein production can be reached by perfusion operation. Through the continuous removal of waste metabolites and supply of nutrients, steady-state (SS) conditions are achieved after a certain transient period, where the conditions inside the reactor are not only uniform in space but also constant in time. Such stable conditions may have beneficial influences on the reduction of product heterogeneities. In this study, we investigated the impact of perfusion cultivation on the intracellular physiological state of a CHO cell line producing a monoclonal antibody (mAb) by global transcriptomics and proteomics. Despite stable viable cell density was maintained right from the beginning of the cultivation time, productivity decrease, and a transition phase for metabolites and product quality was observed before reaching SS conditions. These were traced back to three sources of transient behaviors being hydrodynamic flow rates, intracellular dynamics of gene expression as well as metabolism and cell line instability, superimposing each other. However, 99.4% of all transcripts and proteins reached SS during the first week or were at SS from the beginning. These results demonstrate that the stable extracellular conditions of perfusion lead to SS also of the cellular level.

Numerical Study of Soft Colloidal Nanoparticles Interaction in Shear Flow.

The mechanical behavior of nanoparticle assemblies depends on complex particle interactions that are difficult to study experimentally. Depending on the nanoparticle morphology, these interactions could lead to adhesive and elastic-plastic behavior during contact deformation. The aim of this research is to study the effect of contact interactions between polymer nanoparticles and their impact on the macroscopic properties of formed aggregates. For this purpose, the discrete element method (DEM) was used to develop an interaction model combining elastic-plastic deformation and adhesion to study the behavior of spherical polymeric nanoparticles. Initially, a pair of particles interacting in the normal direction was simulated to evaluate the effect of adhesion and plastic deformation in the pull-off force of the contact. Based on these results, the simulations were extended to a dispersed system of nanoparticles, in which multibody interactions become dominant. Considering the aggregation between the nanoparticles induced by a shear flow, we performed an analysis of the number of aggregates and aggregates size in time to characterize the strength of clusters formed during the process. The simulation results showed that the interaction strength upon breakage of the clusters, correlating with the aggregates size, depends on the nanoparticle's softness. In this way, we verified that the type of contact interaction directly influences the macroscopic mechanical response of nanoparticle assemblies. Therefore, our model represents a new way of predicting the mechanical behavior of polymer nanoparticle systems and of optimizing it by adjusting primary particle properties.