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In this study, vitamin B12, the most chemically complex and the largest molecule among all the vitamins, was successfully incorporated into zein microstructures via electrospinning and spray drying techniques. Scanning electron microscopy analysis revealed that different microstructures were obtained by electrospinning technique: films, microparticles and electrospun fibres. The vitamin B12 films presented a smooth surface and had around 90% of encapsulation efficiency. Vitamin B12-encapsulated zein microbeads, with a size of around 3 μm, were formed showing an efficiency of encapsulation of 91%. Electrospun fibres exhibited ribbon-shaped morphologies and had an encapsulation efficiency of 100%. By spray drying technique, wrinkled zein microparticles with vitamin B12 were produced with an encapsulation efficiency and product yield ranging between 71 and 95% and 67–83%, respectively. Kinetic models were applied to the experimental release profiles. The Weibull kinetic model showed the best fitting with the experimental data. The main drug transport mechanism associated to the experimental data is the Fickian diffusion (case I transport). The results suggest that the produced zein microstructures via spray drying and electrospinning techniques can be used as promising and effective alternative food and nutraceutical delivery systems.

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.

Crystalline lactose microparticles with uniform size and spherical shape are greatly desirable for various applications, but still challenging. Herein, uniform lactose microspheres with high crystallinity were fabricated via spray drying lactose/polyethylene glycol (200 Da) (PEG 200) combined with ethanol/water post-treatment process. The effects of feed solution composition and ethanol/water volume ratio on particle size, morphology, density, crystal property and hygroscopicity were investigated. The obtained spherical lactose/PEG 200 microparticles were partially crystallized (30-50%), exhibiting dominant crystal forms of anhydrous Lα and Lβ. After removing PEG 200 by ethanol/water, the resulting microparticles remained uniform and spherical with enhanced crystallinity (92.90 ± 1.40%), high Lα·H2O content (68.57%) and ultra-low hygroscopicity (0.29%). Possible mechanism of “micro-zone competitive dissolution-reprecipitation” was proposed to reveal the influence of PEG 200 and ethanol/water volume ratio on promoting crystallinity and maintaining spherical morphology of lactose microparticles. This work provides a promising and up-scalable way to manufacture spherical crystalline microparticles.

The number of studies on the surface composition of microparticles obtained by spray drying has increased due to the interest in understanding the relationship between the characteristics of these microparticles and the oxidation stability of encapsulated bioactive compounds. The aim of this study was to evaluate the effect of emulsification techniques on the distribution of components on the surface, microstructure, and physicochemical properties of encapsulated β-carotene microparticles obtained by spray drying. Emulsions created by microfluidization and observed by XPS showed a greater presence (11.35–16.82%) of hydrophilic amino acids (histidine, glycine, serine, threonine) on the surface. Emulsions obtained by rotor/stator system exhibited low encapsulation efficiency (9.1–46.0%), and the microparticles presented a high number of surface irregularities (shrinkage and dents) compared to the microfluidization samples. In contrast, emulsions obtained by microfluidization showed shorter wetting (12.37–14.47 min) and solubility times (25.66–30.22 min), attributed to the percentage of protein on the surface of microparticles. The characteristics of the microparticles provided by the microfluidizer could help in the design of fast-hydration and dispersion powder products by spray drying.

Real (diabatic) spray drying processes have heat loss that affects drying kinetics. The heat loss depends on process parameters and on the type of spray drying equipment. Practically, heat loss can be determined by evaporating the solvent of a specific spray drying process with measurement of the outlet temperature after process equilibration. In this work, models to calculate the droplet evaporation time from an adiabatic (perfectly insulated) spray drying process are further developed to take heat loss into account. Comparison of different calculation models from water evaporation trials on a modified Buchi lab spray dryer with results from ANSYS 13.0 CFD simulations, show a good agreement for the introduced equations where heat loss is considered. The advantage of knowing the droplet evaporation time is that it condenses all relevant parameters of a specific spray drying process including material properties of the solvent to one single parameter affecting evaporation kinetics. The knowledge of the droplet evaporation time is of significant importance for scale-up activities, process transfers and optimizations as well as for particle engineering purposes.

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.

Face centered central composite design was used to investigate the effect of spray drying process parameters (inlet temperature, atomization pressure and feed flow rate) on selected quality parameters of whole camel milk. During storage by freezing, the integrity of camel milk fat globules is maintained with observed aggregation. Whole camel milk contains 12.18% total solids, 3.5% protein and 3.99% [w/w] lactose whereas for the powders, the total solids content was in the range of 94–97%, protein 22–29% and lactose 27–31% [w/w]. By combining response surface methodology with desirability function, the spray drying process of whole camel milk was optimized with objectives of maximizing the yield and minimizing undesired quality degradation parameters. Consequently, it was possible to recover 62% of total solids without affecting the desired aspects of the final physico-chemical properties of powders (minimum insolubility index of 0.1 mL and surface fat content of 4.2% [w/w]) with targeted final moisture content of 4.5% [w/w]. These properties would make the powders safe during extended period of storage.

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.

In this work, a ternary phase diagram was developed for a Niclosamide-urea co-crystal (NCS-UR) in isopropanol (IPA) using a combination of slurry and solvent addition methods. The ternary phase diagram showed that solubility of Niclosamide and urea differed by an order of magnitude in IPA, leading to an incongruently saturating system. Spray drying was explored as a method to generate NCS-UR. Co-crystals with small, uniform particle size were successfully prepared by spray drying from equimolar solutions with yield up to 73%. Co-crystals were phase pure by X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) from all conditions explored. Somewhat similar particles were obtained at inlet temperature of 70 °C (mean size of 2.0 μm) compared to 85 °C (2.8–3.4 μm). Based on the TPD, isolating phase pure co-crystal through solution crystallization in IPA would require excess urea. However, spray drying did not require excess co-former. The in-vitro solubility of NCS-UR was compared to anhydrous NCS in biorelevant media. NCS-UR did not give improvement in solubility at 1 h or 24 h. Overall, this work showed that spray drying is a feasible process for preparing phase pure co-crystals for an incongruently saturating system and simultaneously generating micron size particles.

In recent years, many fast drying techniques such as spray-drying are being explored as alternatives to biopharmaceutical freeze-drying. Thus, it is essential to understand how the processability of commonly used excipients will be affected when these new techniques are employed. This study reports a series of observations outlining how the thermally-induced oxidative degradation of polysorbates (PS) evolves in liquid to solid transitions, such as those expected in spray-drying. Firstly, the impact of different evaporation rates on the oxidative degradation of aqueous solutions of two different PS types namely, PS20 and PS80, were screened via evaporative solvent casting. The latter revealed that the evaporation rate could critically impact the rate-limiting steps of PS thermal oxidation. In addition, the potential of saccharides as excipients to mitigate the thermal oxidation of PS80 under slow and fast evaporation conditions was investigated. Five different saccharide excipients were screened, i.e., trehalose dihydrate, maltodextrin, hydroxypropyl-β-cyclodextrin, and Dextran 40. Under slow evaporation conditions, only trehalose dihydrate seemed to be beneficial in avoiding the thermal oxidation of PS80. For fast evaporation conditions, hydroxypropyl-β-cyclodextrin prevented the oxidative degradation of PS80. This implies that distinct strategies to mitigate PS oxidative degradation might be necessary depending on the drying process and rates.

Despite the advantages of targeting the pulmonary route through Dry Powder Inhalers (DPIs), the efficient delivery of biologics to the lungs still presents a considerable challenge: the generation of a powder with adequate aerodynamic properties while preserving the integrity of the biologic. Hence, the particle engineering technology employed to meet this balance plays a pivotal role. The present work describes a proof-of-concept study to investigate the effect of spray drying (SD) outlet temperature (Tout), atomization flow rate (Rotatom) and feed flow rate (Ffeed) on powder properties such as particle morphology and aerodynamic performance but also on the enzyme activity and protein conformational stability of a trehalose:leucine spray-dried powder featuring Cu,Zn-superoxide dismutase (Cu,Zn-SOD). This enzyme, often implicated in a broad spectrum of oxidative stress related diseases, from cystic fibrosis to rheumatoid arthritis, was used as a model Active Pharmaceutical Ingredient (API). Morphology and aerodynamic performance of the SD powders were determined by scanning electron microscopy (SEM), focused ion beam – SEM, laser diffraction and Andersen Cascade Impaction. For each SD run, enzyme activity retention (EAR) was measured by spectrophotometry and the protein melting temperature by differential scanning fluorimetry. To further understand the interaction between input and output variables, a statistical analysis was performed using SIMCA v13.0.3.0 software. Cu,Zn-SOD:trehalose:leucine spray dried powders were successfully generated upon different processing conditions, displaying fine particle fractions of ≈60% and EAR ranging from 50–80% with no loss of protein conformational stability. This technology thus proved to be suitable to prepare Cu,Zn-SOD based DPI powders within the considered working ranges.

Objective Fluoride (F)-releasing restoratives typically are either weak mechanically or release only low levels of F ions. The objectives of this study were to: (1) develop a novel photo-cured nanocomposite with strong mechanical properties and high levels of sustained F ion release via a two-step “co-precipitation + spray-drying” technique to synthesize CaF2 nanoparticles (nCaF2); and (2) investigate the effect of spray-drying treatment after co-precipitation of nCaF2 on mechanical properties and F ion release of composite. Methods Two types of CaF2 particles were synthesized: A co-precipitation method yielded CaF2cp; “co-precipitation + spray-drying” yielded nCaF2cpsd. Composites were fabricated with fillers of: (1) 0% CaF2 + 70% glass; (2) 10% CaF2cp + 60% glass; (3) 15% CaF2cp + 55% glass; (4) 20% CaF2cp + 50% glass; (5) 10% nCaF2cpsd + 60% glass; (6) 15% nCaF2cpsd + 55% glass; and (7) 20% nCaF2cpsd + 50% glass. A commercial F-releasing nanocomposite served as control. Results The nCaF2cpsd had much smaller particle size (median = 32 nm) and narrower distribution (22–57 nm) than CaF2cp (median = 5.25 μm, 162 nm–67 μm). The composite containing nCaF2cpsd had greater flowability, flexural strength, elastic modulus and hardness than CaF2cp composite and commercial control composite. At 84-day immersion in water, the nanocomposites containing 20% nCaF2cpsd had 65 times higher cumulative F release, and 77 times greater long-term F-release rate, than commercial control. Conclusions A novel two-step “co-precipitation + spray-drying” technique of synthesizing nCaF2 was developed. The photo-cured nanocomposite containing 20% nCaF2cpsd possessed strong mechanical properties and excellent long-term F-release ability, and hence is promising for dental restoration applications to inhibit secondary caries.

The aim of this work was to encapsulate of citrulline extract from watermelon rind (by-product) by spray drying. Two different pectins were probed as wall materials in addition to maltodextrin. A Box-Behnken design was applied and three different parameters were evaluated as factors: commercial pectin (CP) concentration, orange produced pectin (OPP) concentration, and inlet air temperature. Different powder properties were evaluated as response variables including drying yield and encapsulation efficiency. The spray drying process was optimized by the desirability function. Higher drying yields, moisture contents and encapsulation efficiencies were reached at higher commercial pectin concentration. The optimal spray drying conditions were also determined. The obtained powder at the optimal conditions was characterized using Modulated differential scanning calorimetry and thermogravimetric analysis. In conclusion, citrulline extract spray-dried powders showed that could be stable during storage, so it might be used as an additive in foods to obtain functional products for human consumption.

Mesoporous graphene and other carbon derivative nanospheres have attracted intensive research attention owing to their many unique characteristics and fascinating properties. However, facile synthesis of these mesoporous nanospheres with a small particle size and controllable morphology is still a grand challenge. Herein, we report a Kirigami-inspired approach to prepare mesoporous spherical graphene oxide (MSGO) particles through spray drying of holey GO sheets. By increasing pore size and porosity of the holey GO sheets, the spray-dried particles underwent the transition from rough crumpled structure to smooth spherical shape. The prepared MSGO particles have tunable diameters smaller than 200 nm and a high specific surface area of 503 m2/g, which enable consistent high-efficiency physical adsorption removal of organic dyes such as Rhodamine B from polluted water with a high adsorption rate of 335.6 mg/(g min). Moreover, the reported synthetic route provides the freedom to easily incorporate other functional nanoparticles such as TiO2, CuO or post-dope MSGO with nitrogen elements for construction of multifunctional composite particles with tailorable structures, which may enable a broad range of promising applications.

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.

The graphene oxide powder (GOP) obtained from the spray drying process often exhibits poor re-dispersibility which is considered due to the partial reduction of GO sheets. The reduction of drying temperature can effectively increase the re-dispersibility of GOP, but result in a decreased drying efficiency. Herein, we found that the re-dispersibility of GOP is strongly affected by its microstructure, which is determined by the feed concentration. With the increase of feed concentration, the GO nanosheet assembly varies from the disordered stacking to relatively oriented assembly, making the morphology of the GOP transform from ball-like (the most crumpled one) to flake-like (the least crumpled one), and the 0.8 mg·ml−1 is the threshold concentration for the morphology, structure, and re-dispersibility change. Once the feed concentration reaches 0.8 mg·ml−1, the appearance of the nematic phase in droplet ensures the relatively oriented assembly of GO sheets to form the layered structure with a low crumpling degree, which greatly improves the polar parts surface tension of the solid GOP, making the GOP easier to form hydrogen bonding with water during the redispersion process, thus stabilizing dispersion. This work provides useful information for understanding the relationships between the morphology, microstructure, and final re-dispersibility of GOPs.

Insecticides based on Azadirachta indica have been demonstrated as useful in pest control and bioinsecticides that are microencapsulated can reduce the amount of product utilized, and minimize impacts on the environment and human health. The objective of this study was to optimize drying, and evaluate the release and degradation kinetics of microencapsulated extracts from A. indica seeds. The Box-Behnken model (33) and surface response methodologies were used to find the best spray drying conditions for the chosen variables. They were: in-let temperature of 160 °C, feed flow of 3.3 mL/min, and nozzle diameter of 0.7 mm. The drying efficiency and EE under these conditions were respectively 71.15% ± 2.18 and 56.88% ± 0.28. In the release kinetics study, the release time for Azadirachtin (100%) was 20h. The 50% photo-degradation time for Azadirachtin was 21.07 days. Our results support industrial scale-up studies, and can help application measures in the field.

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.

Background Nowadays, there is a growing trend in the consumption of bioactive food ingredients and their use in the production of functional foods. Since these bioactive components are very sensitive to process and environmental conditions, and also to deliver them appropriately into our body, encapsulation technology has been emerged as a promising solution to achieve these goals. Spray drying is one of the most common and popular techniques for the encapsulation and drying of food ingredients. Scope and approach With the emergence of nanotechnology and its many benefits, scientists have focused on the development of nano-based materials and techniques in the food industry. Bioactive ingredients loaded in nanoparticles and nanocarriers could be applied as helpful nano delivery systems for the production of functional foods and nutraceutical delivery systems. The problem with conventional spray drying is the limited possibility of obtaining powder nanoparticles as the cyclone separating units can not result in collecting those very small particles. Nano spray dryer has been designed successfully to address this issue. This article will focus on the fundamentals of a nano spray drying system and its applications in the food industry. Key findings and conclusions The scientific findings so far confirm that the nano spray dryer technology has been well-practiced in the drying and encapsulation of different food ingredients such as vitamins and minerals, phenolic compounds, carotenoids, and essential oils and fatty acids, although it is still at the beginning. It is possible to produce powder nanoparticles with a uniform size distribution through the ultrasonic atomizer in this system and electrostatic separation unit. A very small volume of sample is needed for this instrument which is a big advantage for expensive raw ingredients. The main challenge is that there is no possibility to conduct pilot or industrial scale experiments with this nano spray dryer system for the commercialization of the relevant products that could be available in the coming years.

Zinc sulphate heptahydrate was microencapsulated by spray-drying using maltodextrin, HI-CAP® 100 and whey protein isolate as wall materials. Spray-drying conditions were optimised using Taguchi orthogonal array design with encapsulation efficiency and bulk density as responses. The influences of wall material, wall material to zinc ratio and inlet air temperature were evaluated. Microcapsules prepared with HI-CAP® 100 in 20:1 loading ratio at 185 °C had maximum encapsulation efficiency (92.65%), whereas 10:1 ratio yielded maximum bulk density (541.2 kg/m3). SEM micrographs revealed the spherical structure of microcapsules, while EDX confirmed the presence of zinc in the microcapsules. SEM micrographs, FTIR and XRD analyses showed that zinc was successfully encapsulated as microcapsules. The tapped, bulk and particle densities of zinc microcapsules were in the range of 586.15–698.15, 437.40–541.20 and 1263.25–1436.50 kg/m3, respectively, while flowability was ‘fair' to ‘passable’. The adsorption isotherm of microcapsules was sigmoidal, and was described by GAB model. Fortification of milk with zinc microcapsules did not affect its inherent organoleptic qualities.

This study aimed to evaluate the potential of maltodextrin (MD) combination with gum arabic (GA), and whey protein isolate (WPI) on the microencapsulation of gurum seeds oil by a spray-drying method. Three formulations of protein-based (PB) (WPI: MD, 2:1), carbohydrate-based (CHOB) (GA: MD, 2:1), and mixed (MIX) (WPI: GA: MD, 1:1:1) wall materials were designed. The moisture content and water activity were in the range of 1.65–3.67% and 0.17–0.31, respectively, which is suitable for long-term storage. The best results were achieved when gurum seed oil was microencapsulated with carbohydrate-based, where it had the highest microencapsulation yield (92.80%) and microencapsulation efficiency (97.38%). Carbohydrate-based showed the highest relative crystallinity (32.25%) and the temperature of the glass transition (58.20 °C). FT-IR revealed that the oil was well encapsulated in the microcapsules. SEM of microcapsules showed spherical shapes without any apparent cracking on the surfaces. During the oxidative stability study, carbohydrate-based microencapsulation was the wall material that best protected the active materials against lipid oxidation.

Background Spray drying is still the most important technique for the microencapsulation of bioactive ingredients. It makes possible to create easy-handling powdered microcapsules from liquid material in one simple and easy-scalable operation. However, the selection of proper wall material is crucial to obtain high retention of biological activity, high encapsulation efficiency, beneficial physical properties, high bioavailability and storage stability (both in terms of physical and biological properties). Scope and approach During last decade there was a trend to apply new types of biopolymers as wall materials, as additional compounds or as complete substitutions to conventionally used maltodextrins and gum arabic. Such approach provides new “clean label”, “green label” and health-promoting properties to the obtained microcapsules. Moreover, it creates also new possibilities for waste valorization. On the other hand, there is still a question about the technological suitability and properties of such biopolymers applied as wall materials. The review summarizes the investigations done in this topic during last decade. Key findings and conclusions the delivery of additional health benefits with wall materials and sustainable methods to obtain them, is a current trend in spray drying encapsulation.

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.