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Porous particles composed of 2,2,6,6-tetramethylpiperidinyl-1-oxyl-oxidized cellulose nanofiber (TOCN) as building block, i.e., porous TOCN particles, are attracting attention due to their environmental friendliness, superior properties, such as easy handling, large surface area, and high adsorption capacity. However, the instability of TOCNs in aqueous environments limits their applications. An effective solution to improve water resistance of TOCN particles is to reduce the hydrophilicity of TOCNs by forming chemical bonds with a cross-linker. In this study, Carbodilite, a common, easy-to-use, commercially available cross-linker with carbodiimide groups, was used to investigate a chemical cross-linking strategy for porous TOCN particles prepared by spray drying. The water resistance of cross-linked TOCN particles was evaluated through morphological observation by SEM images. The presence of polycarbodiimide significantly increased water resistance of cross-linked TOCN particles up to 24 h. This study demonstrates the trade-off between water resistance and adsorption efficiency according to cross-linker concentrations. These data are useful for interface science of TOCNs in liquids, assisting in controlling specific properties of porous TOCN particles for particular applications in adsorption and separation.

In this study we synthesized Li-rich Li1.2Ni0.13Mn0.54Co0.13O2 (LMNCO) as a composite cathode material through a two-step spray-drying method, using transition metal (TM) acetates and citric acid (CA, as a chelating agent) at various molar ratios and then calcining at various temperatures for various periods of time. This two-step spray-drying method created hierarchical nano/micro-sphere structures of the LMNCO cathode material. The LMNCO cathode exhibited the best electrochemical performance when synthesized with a TM:CA ratio of 3:2, a calcination temperature of 900 °C, and a calcination time of 5 h. This as-prepared LMNCO composite was then modified with polyimide (PI) at various weight ratios (PI/LMNCO = 0.5, 1.0, and 1.5 wt%) to improve its electrochemical properties. Among the various structures, the LMNCO cathode material coated with 1.0 wt% of PI at a layer thickness of approximately 1.88 nm achieved the best initial discharge capacities. This modified electrode also displayed enhanced cycle stability, with over 93.3 and 87.9% of the capacity retained after 30 cycles at 0.1C and 100 cycles at 1C, respectively. In comparison, the capacity retention of the unmodified LMNCO electrode measured under the same conditions was no more than 91.3% at 0.1C and 70.1% at 1C. Thus, surface modification with PI was an effective method for improving the coulombic efficiency, discharge capacity, and long-term cycling performance of the LMNCO cathode. Such PI-coated LMNCO composite cathode materials appear to be potential candidates for use in next-generation high-performance lithium-ion batteries.

In this work, a hierarchical reduced graphene oxide (RGO) supportive matrix consisting of both larger two-dimensional RGO sheets and smaller three-dimensional RGO spheres was engineered with ZnO and SnO2 nanoparticles immobilized. The ZnO and SnO2 nanocrystals with controlled size were in sequence engineered on the surface of the RGO sheets during the deoxygenation of graphene oxide sample (GO), where the zinc-containing ZIF-8 sample and metal tin foil were used as precursors for ZnO and SnO2, respectively. After a spray drying treatment and calcination, the final ZnO@SnO2/RGO-H sample was obtained, which delivered an outstanding specific capacity of 982 mAh·g-1 under a high current density of 1000 mA·g-1 after 450 cycles. Benefitting from the unique hierarchical structure, the mechanical strength, ionic and electric conductivities of the ZnO@SnO2/RGO-H sample have been simultaneously promoted. The joint contributions from pseudocapacitive and battery behaviors in lithium-ion storage processes bring in both large specific capacity and good rate capability. The industrially mature spray drying method for synthesizing RGO based hierarchical products can be further developed for wider applications.

Zirconium carbide hollow microspheres (ZrC HMs) were fabricated via spray drying process and polymer-derived ceramics technique. The stable and homogeneous ZrC precursor solution can be prepared by mixing polyzirconoxane (PZO), phenolic resin (PR), curing agent p-toluenesulfonic acid (TsOH) and solvent n-propanol. The precursor solution was spray-dried to form hollow precursor microspheres. During the spray drying process, morphology of the hollow precursor microspheres can be regulated by adjusting temperature of inlet hot N2, concentration of precursor solution and the amount of curing agent TsOH. The prepared hollow precursor microspheres were carbonized at 700 °C and then converted into ZrC HMs by carbothermal reduction reaction above 1500 °C. During the pyrolysis process, nanosized ZrO2 grains produced by PZO decomposition are evenly dispersed, so is the carbon produced by PR pyrolysis, as prevents overgrowth of ZrO2 grains in the following process, even when it is changed to ZrC. ZrC HMs maintained excellent spherical morphology at temperatures of 1500–1900 °C, with particle size Dv(50)=16.4–18.7 μm, which enable their promising applications in ultra-high temperature insulation material. This preparation method is simple and can be prepared on a large scale.

Multifunctional fillers are greatly required for dental resin composites (DRCs). In this work, a spray dryer with a three-fluid nozzle was applied for the first time to construct high-performance complex nanoparticle clusters (CNCs) consisting of different functional nanofillers for dental restoration. The application of a three-fluid nozzle can effectively avoid the aggregation of different nanoparticles with opposite zeta potentials before the spray drying process in order to construct regularly shaped CNCs. For a SiO2–ZrO2 binary system, the SiO2–ZrO2 CNCs constructed using a three-fluid nozzle maintained their excellent mechanical properties ((133.3 ± 4.7) MPa, (8.8 ± 0.5) GPa, (371.1 ± 13.3) MPa, and (64.5 ± 0.7) HV for flexural strength, flexural modulus, compressive strength, and hardness of DRCs, respectively), despite the introduction of ZrO2 nanoparticles, whereas their counterparts constructed using a two-fluid nozzle showed significantly decreased mechanical properties. Furthermore, heat treatment of the SiO2–ZrO2 CNCs significantly improved the mechanical properties and radiopacity of the DRCs. The DRCs containing over 10% mass fraction ZrO2 nanoparticles can meet the requirement for radiopaque fillers. More importantly, this method can be expanded to ternary or quaternary systems. DRCs filled with SiO2–ZrO2–ZnO CNCs with a ratio of 56:10:4 displayed high antibacterial activity (antibacterial ratio > 99%) in addition to excellent mechanical properties and radiopacity. Thus, the three-fluid nozzle spray drying technique holds great potential for the efficient construction of multifunctional cluster fillers for DRCs.

The surfactants used for emulsion is one of the best techniques for microencapsulation of lactic acid bacteria (LAB) since it is economical. The biosurfactants have many advantages such as lower toxicity, higher biodegradability. In this study, microcapsules were prepared via spray drying using Bifidobacterium adolescentis species cultured in soy milk extract with biosurfactant prepared using Alcaligenes piechaudii CC-ESB2 to improve their powder properties. The soy milk was used to increase the health benefits instead of the milk. The optimum bacterial strain viability, water activity, and moisture content of the microcapsules were achieved at a spray dryer inlet/outlet temperature of 120/60°C. The composition of the carrier affects the particle size of the microcapsules. Using 90% maltodextrin (MD), 5% isomalto-oligosaccharide syrup (IMOS) and 5% biosurfactant as a carrier increased the viability of the LAB. Scanning electron microscope observations showed that the LAB microcapsules were able to effectively retain their completeness. Furthermore, microcapsules added with a biosurfactant prepared using A. piechaudii CC-ESB2 displayed significantly better flow properties than those without the surfactant and biosurfactant, which indicates that the biosurfactant assists in enhancing the powder properties of the microcapsules. It also has sufficient biological activity as a LAB product because the probiotics exceed 10

Spray-dried products, such as synthetic peptides and hormones, have already been approved by the U.S. Food and Drug Agency and the European Medicines Agency, while spray-dried antibodies or interleukins, are not yet available on the market. Concerning the latter group, knowledge on whether and how spray-drying (SD) can be performed without adversely affecting their biological activity is lacking. Accordingly, this study aimed at establishing a SD process (Buchi B-90 spray dryer) using three Interleukin-8 based proteins (7–74 kDa) that were dispersed in phosphate buffered saline to maintain their stability. A Box-Behnken Design of Experiments was conducted to identify the appropriate process parameters taking into account the thermal stability of interleukin-8. In parallel, a FD process was developed. Both powders were stored for up to 12 weeks. Powder characterization included residual moisture evaluation and the mean particle size of the SD powder was investigated with Laser Diffraction Analysis. The hydrodynamic volume was measured via size exclusion chromatography and sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The secondary structure of the model proteins in the solid state was assessed with Fourier-transformation infrared spectroscopy for detecting the protein folding patterns and reconstituted with Circular Dichroism Spectroscopy. Finally, the binding affinity was studied with Surface Plasmon Resonance and Isothermal Fluorescence Titration, the protein stability with Chaotropic Unfolding, and the activity studies were carried out with the chemotaxis assay. The results showed that SD and FD powders with a residual moisture of less than 5 wt% were obtained. The interleukins showed no unfolding upon processing, neither in solid state nor reconstituted. Oligomerization was observed for FD, but not for SD interleukins. However, the unfolding, binding affinity and activity of all interleukins examined did not decrease in neither SD nor FD powders, even after 12 weeks of storage. Thus, it can be concluded that SD of interleukin formulations at outlet temperatures close to ambient temperature is a promising process for transferring them into a stable powder.

5 Figuras.-- 8 Tablas, A factorial design was performed for the microencapsulation of chia oil by spray drying at pilot-scale, to validate the results obtained previously at laboratory scale in a Büchi-B290. The effects of drying-air inlet (Tinlet) and outlet (Toutlet) temperatures in a Niro Production Minor on the solid yield, thermal efficiency, theoretical droplet evaporation times, and physico-chemical properties of powders were analyzed. The theoretical droplet evaporation times (0.31−0.54 s) were calculated considering the constant and falling rate periods and a negligible relative velocity between spray and air. Critical diameters between 31.77–41.57 μm were estimated for microcapsules, depending on the process conditions. After scale-up of the spray drying operation, higher solid yields (74.24–79.79%), thermal efficiencies (27.56–73.19%), encapsulation efficiencies (96.97–98.57%), and enhanced flowability of products, compared with experiments at laboratory scale, were observed. Moreover, the scale-up did not affect the chemical composition of microencapsulated oils, their fatty acid composition before and after in-vitro digestion processes. A global optimization was performed at pilot-scale and the process conditions that simultaneously optimized all the responses was 160 °C × 90 °C (Tinlet × Toutlet)., This research was financed with grants from Consejo de Investigaciones Científicas y Técnicas (CONICET), Argentina. The authors would like to acknowledge the Iberoamerican Project CYTED 119RT0567. María Gabriela Bordón would like to acknowledge the fellowships from CONICET and from Secretaría General Iberoamericana-Fundación Carolina.

The core-shell 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-Trinitrotoluene (CL-20/TNT) composite was prepared by spray-drying method in which sensitive high energy explosive (CL-20) was coated with insensitive explosive (TNT). The structure and properties of different formulations of CL-20/TNT composite and CL-20/TNT mixture were characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Laser particle size analyzer, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), differential scanning calorimetry (DSC), impact sensitivity test and detonation performance. The results of SEM, TEM, XPS and XRD show that ϵ-CL-20 particles are coated by TNT. When the ratio of CL-20/TNT is 75/25, core-shell structure is well formed, and thickness of the shell is about 20–30 nm. And the analysis of heat and impact show that with the increase of TNT content, the TNT coating on the core-shell composite material can not only catalyze the thermal decomposition of core material (CL-20), but also greatly reduce the impact sensitivity. Compared with the CL-20/TNT mixture (75/25) at the same ratio, the characteristic drop height of core-shell CL-20/TNT composite (75/25) increased by 47.6% and the TNT coating can accelerate the nuclear decomposition in the CL-20/TNT composites. Therefore, the preparation of the core-shell composites can be regarded as a unique means, by which the composites are characterized by controllable decomposition rate, high energy and excellent mechanical sensitivity and could be applied to propellants and other fields.

In this study metronidazole drug was encapsulated by hydroxypropyl methylcellulose and polyvinylpyrrolidone polymers from solutions using nano spray drying technology. The influence of the process parameters and formulation variables were investigated on product morhology and structure, production yield and entrapment efficiency. The use of surface active admixtures (polyvinyl alcohol, Tween-80 and Pluronic F68) increased the product yield substantially. The entrapped metronidazole was partially in crystalline and amorphous state in both amorphous polymers as confirmed by DSC and powder X-ray diffraction measurements. In the composites with hydroxypropyl methylcellulose the degree of crystallinity was between 50.2 and 81.0%, and with polyvinylpyrrolidone between 35.0 and 50.0% (with respect to the drug content). Melting point decrease phenomena was observed by differential scanning calorimetry between bulk metronidazole and spray dried products. Peak broadening was indicated by powder X-ray diffraction measurements, which could be the result of formation of small drug crystallites. The TEM images showed beside the larger crystals (200–400 nm) a fraction of smaller crystals (20–50 nm in diameter), which are in good correlation with the calculated coherent scattering domain sizes of 19–87 nm based on X-ray data. The drug-polymer composites produced by nano spray drying process were identified as crystalline-amorphous nanostructured micronized solid dispersions.

Spray drying is a technique that can be used to stabilize biopharmaceuticals, such as vaccines, within dry particles. Compared to liquid pharmaceutical products, dry powder has the potential to reduce costs associated with refrigerated storage and transportation. In this study, spray drying was investigated for processing an adjuvanted tuberculosis subunit vaccine, formulated as an oil-in-water nanoemulsion, into a dry powder composed of microparticles. Applying in-silico approaches to the development of formulation and processing conditions, successful encapsulation of the adjuvanted vaccine within amorphous microparticles was achieved in only one iteration, with high retention (>90%) of both the antigen and adjuvant system. Moisture-controlled stability studies on the powder were conducted over 26 months at temperatures up to 40 °C. Results showed that the powder was physically stable after 26 months of storage for all tested temperatures. Adjuvant system integrity was maintained at temperatures up to 25 °C after 26 months and after one month of storage at 40 °C. The spray-dried product demonstrated improved antigen thermostability when stored above refrigerated temperatures as compared to the liquid product. These results demonstrate the feasibility of spray drying as a method of encapsulating and stabilizing an adjuvanted vaccine.

International audience; A numerically effective approach was developed for the modeling of spray-drying of colloidal suspensions. This approach was based on the integration of two models. The first is a phenomenological and radially symmetric model accounting for the drying of single-droplets, while the second employs computational fluid dynamics (CFD) simulations to account for the gas flow conditions and atomization in a spray dryer. Experiments were also conducted on single suspension droplets trapped in an acoustic field as well as on droplets in a mini-spray dryer. The predictions of the models were found to be in reasonable agreement with the experimental data, in terms of droplet shrinking and buckling, particle yield, and spatial distribution in the spray dryer mockup.

Polyester fabric (PET fabric) has aroused widespread attention from people thanks to the advantages of smooth feel, easy washing, quick-drying, high strength, and chemical resistance. However, PET fabric's wide application has been limited by its hydrophobicity, poor resistance to bacterial contamination, and static accumulation. Herein, a super-hydrophilic PET fabric was achieved via a spray-drying layer-by-layer self-assembly method for comfortable garment manufacturing. The as-prepared PET fabric exhibited good superhydrophilicity, excellent antistatic property, and durable antibacterial performance. Moreover, the water contact angle of the treated fabric decreased to 0° from 121° of the original PET fabric, and the capillary height also increased from 7.1 cm to 21.4 cm. Besides, the treated fabric showed a durable antibacterial rate of 99.5% against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) after ten standard washing cycles. The prepared fabric was also identified with good cytocompatibility, making it a good material for garments in real life. Promisingly, this novel approach can be easily integrated into the finishing of textiles and is expected to be applied to various substrates with superhydrophilic and antibacterial properties.

Co-encapsulation of retinoic acid (RA), curcumin and/or resveratrol into microparticles composed by alginic acid sodium and the ethyl cellulose + polyethylene glycol (EC + PEG) blend was proposed for the protection and co-delivery of these bioactive compounds. The final aim is to take benefit of combined therapeutic potential related to these molecules and use loaded microparticles obtained by spray-drying to improve the treatment of acute promyelocytic leukemia (APL). Alginic acid sodium-based emulsions were characterized regarding rheological properties (i.e. viscosity), stability and droplet size distribution. Biopolymer- and synthetic polymer-based microparticles loaded with RA, RA + curcumin, RA + resveratrol and RA + curcumin + resveratrol were produced with a product yield between 10 and 35 %. The obtained microparticles exhibited a variable form, a morphology that varied between a slightly and high rough surface and a mean diameter that ranged from 2.97 ± 0.04 and 88 ± 3 μm. Encapsulation efficiency was significantly influenced by the encapsulating agent(s) used in the microparticles formulations. The bioactive compounds that were co-encapsulated showed a similar release profile.

To increase their stability, therapeutic (or monoclonal) antibodies (mAbs) are often formulated as solids by using a variety of drying techniques, e.g. freeze-drying, spray-drying, or spray freeze-drying. The addition of excipients is required to preserve stability of the protein during the drying process and subsequent storage of the resulting solid form. The addition of low molecular weight excipients, such as amino acids, to sugar based spray- and freeze-dried formulations has been suggested to improve the storage stability of proteins in the dried state. In this study sugars (sucrose, trehalose), amino acids (Gly, Ala, Pro, Ser, Val, Leu, Ile, Gln, His, Lys, Arg, Phe, Trp) and combinations thereof were investigated for their stabilizing effect during spray-drying and subsequent storage and for their reconstitution time reducing effect. Two IgG4 mAbs were used as model antibodies. From an initial screening study, basic and small neutral amino acids, in combination with a sugar, such as sucrose or trehalose, showed reconstitution time reducing and stabilizing properties. Arg in particular displayed excellent reconstitution and stability enhancing properties. Moreover, Arg was the only amino acid providing stabilizing properties comparable to sucrose or trehalose. Previous work by the authors described a statistically substantiated comparison between the three basic amino acids in a sugar containing formulation, albeit limited to a single concentration level [5]. Therefore, a follow-up design of experiments (DoE) study was performed to determine the optimum trehalose/amino acid content required for an optimal protein stability and reconstitution time and to compare the effects of two basic amino acids, Lys and Arg, to those of two neutral amino acids, Gly and Pro. The conducted DoE covered a wide range of trehalose (30-120 mM) and amino acid (50-150 mM) concentrations. The concentration of trehalose was found to be the main contributor to a reduction in reconstitution time and an increase in stability. Here we show that the addition of amino acids such as Gly, Pro, and Lys does not improve stability nor does it reduce the reconstitution time. Of the tested amino acids, only Arg showed a marked reduction in reconstitution time and improvement in stability compared to a trehalose. Moreover, the properties displayed by Arg could justify its application as the main stabilizer in spray-dried mAb formulations, eliminating the need for a sugar matrix altogether. But the weight ratio of stabilizer to protein was found the factor exerting the strongest overall influence on the formulation's reconstitution time and stability. More specifically, sufficient physical stability and an acceptable reconstitution time could be obtained with a protein to stabilizer weight ratio of at least 1:1. ispartof: EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS vol:156 pages:131-142 ispartof: location:Netherlands status: published

Phospholipids constitute biocompatible and safe excipients for pulmonary drug delivery. They can retard the drug release and, when PEGylated, also prolong the residence time in the lung. The aim of this work was to assess the structure and coherence of phospholipid coatings formed by spray drying on hydrophilic surfaces (silica microparticles) on the nanoscale and, in particular, the effect of addition of PEGylated lipids thereon. Scanning electron microscopy showed the presence of nanoparticles of varying sizes on the microparticles with different PEGylated lipid concentrations. Atomic force microscopy confirmed the presence of a lipid coating on the spray-dried microparticles. It also revealed that the lipid-coated microparticles without PEGylated lipids had a rather homogenous coating whereas those with PEGylated lipids had a very heterogeneous coating with defects, which was corroborated by confocal laser scanning microscopy. All coated microparticles had good dispersibility without agglomerate formation, as indicated by particle size measurements. This study has demonstrated that coherent coatings of phospholipids on hydrophilic surfaces can be obtained by spray drying. However, the incorporation of PEGylated lipids in a one-step spray-drying process to prepare lipid coated microparticles with both controlled-release and stealth properties is very challenging. (C) 2020 The Authors. Published by Elsevier Inc.