Search

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.

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.

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.

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.

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.

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.

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.

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.

Tuberculosis is still one of the leading causes of death from a single infectious agent (i.e. Mycobacterium tuberculosis). First line therapy includes per oral administration of high doses of rifampicin over several months and is often times accompanied by the occurrence of unwanted side effects that might limit the patient’s adherence to the therapy. Thus, local antibiotic treatment at the site of infection i.e. the lungs is desirable. Amongst other approaches, spray drying of solutions of rifampicin has been shown as suitable method to produce respirable dry powders. In this work, we present inhalable formulations manufactured via spray drying of aqueous solutions of rifampicin. Powders manufactured were characterized for their aerodynamic and solid state properties, as well as their physical and chemical stability. The main focus of this study was to investigate the mechanism of particle formation using an acoustic levitator. Fine particle fractions of the test formulations ranged from 80 to 89% whereas a reference formulation (a spray dried isopropyl alcoholic solution of rifampicin) showed a lower fine particle fraction of 37%. Acoustic levitator and surface tension experiments showed that interfacial properties of rifampicin lead to early crust formation upon drying of the droplets, which eventually decoupled from the liquid core and formed highly collapsed, low apparent density powders with excellent aerosol properties.

Incorporation of a suitable carrier material or additive with the food ingredients in the spray drying operation has become a common practice to optimize the drying performance and the quality of final products. To achieve those goals, the detailed information and understanding of the carrier material characteristics and the influence are very important. Recently, many studies have developed a new carrier material and conducted a different carrier material formulations to explore its potential and improve the spray-dried powders. Therefore, the knowledge of the present and alternative carrier materials that could be applied in the industry were reviewed.

Microparticles containing the photosensitive spinosad (SP) were obtained using a combination of chitosan (CH) and sodium lignosulfonate (SL) as encapsulating materials to develop a photoprotective system for intake administration. The microparticles were obtained by a spray drying technique and were characterized in terms of morphology (scanning electron microscopy - SEM) and particle size. In vitro release studies showed an initial burst effect that fits very well with the zero order kinetic model and then a slow release of the bioinsecticide, which fits best with the first order model. The results of this work demonstrate that the bioinsecticide carrier system developed with natural polymeric materials presents high stability to photodegradation and adequate insecticide release for use as a strategy to reduce negative impacts on the environment in agronomic practices.

The main objective of this research was to study the chia oil microencapsulation process in a co-current spray dryer. First, the effects of drying air inlet temperature and volumetric feed rate on the air temperature along the dryer, solid yield, physical properties of powders, and the estimated droplet evaporation time were assessed. Second, the evaporation time was predicted by means of a simple fundamental model, based on evaporation in still air and the constant rate period. Third, a global optimization of drying process conditions was performed. The main results showed that a uniform air temperature was found inside the dryer for all the process conditions, evidencing a well-mixed chamber. The estimated values of droplet evaporation times were between 1.23 and 2.55 s. Strong correlations between evaporation times and physical properties of powders (moisture content, surface oil content and encapsulation efficiency) were found. Finally, the process condition that simultaneously optimized dependent variables was 130 °C x 10 mL/min.

In this study, spinel lithium titanate (Li4Ti5O12, LTO) anode materials were synthesized from two titanium sources (P25 TiO2, 100% anatase TiO2) using a spray-drying method and subsequent calcination at various temperatures. The electrochemical performance of both a Li/LTO half cell and a LiNi0.5Mn1.5O4/LTO (LNMO/LTO) full cell were investigated. The electrochemical performance of the LTO material prepared from P25 TiO2 was superior to that of the LTO prepared from 100% anatase TiO2. After modification of LTO material with AlPO4, the LTO coated with 2 wt% of AlPO4 (denoted “2%AlPO4-LTO”) provided the best performances. The specific (delithiation) capacities of the 2%AlPO4-LTO anode material was 189.7 mA h g−1 at 0.1C/0.1C, 184.5 mA h g−1 at 1C/1C, 178.8 mA h g−1 at 5C/5C, and 173.1 mA h g−1 at 10C/10C. From long-term cycling stability tests, the specific capacity at the first cycle and the capacity retention after cycling were 185.5 mA h g−1 and 98.06%, respectively, after 200 cycles at 1C/1C and 182.1 mA h g−1 and 99.18%, respectively, after 100 cycles at 1C/10C. For the LNMO/2%AlPO4-LTO full cell, the average specific capacity (delithiation) and coulombic efficiency after the first five cycles were 164.8 mA h g−1 and 93.30%, respectively, at 0.1C/0.1C. The specific capacities at higher C-rates were 156.1 mA h g−1 at 0.2C/0.2C, 135.7 mA h g−1 at 1C/1C, 97.5 mA h g−1 at 3C/3C, and 46.5 mA h g−1 at 5C/5C. After twenty-five cycles, the C-rate returned to 1C/1C and the specific capacity, coulombic efficiency, and capacity retention were maintained at 134.1 mA h g−1, 99.17%, and 98.82%, respectively.

This work studied pineapple-mint juice drying by spray drying. The effect of 0, 3, and 15% of maltodextrin addition in the solution fed in the spray dryer was evaluated. The results showed that it is possible to dry pineapple-mint juice without a carrier agent. A two-level full factorial design of experiments was applied to quantify the effect of spray drying conditions (including the addition of 3% maltodextrin on pineapple-mint juice) on powder physicochemical properties. The estimated effects demonstrated that all variables have affected responses (except powder solubility). Interested in investigating pineapple-mint drying without maltodextrin, the two-level factorial design was further expanded to a central composite design, and additional experiments were realized, resulting in preservation of the natural green color of pineapple-mint juice, and a yield of 35%. The results suggest that mint may help in pineapple-mint juice drying.

Active pharmaceutical ingredient (API) nanosuspensions from naproxen (Nap) and itraconazole (Itra) stabilized with Kollidon®VA64 (KVA) and sodium dodecyl sulfate (SDS) were produced in two different size classes each by wet media milling. These API nanosuspensions were spray dried with lactose, trehalose and sucrose as matrix formers in different proportions and at different drying temperatures (Toutlet). Toutlet as well as the API content significantly influenced the redispersibility of the API nanoparticles. It could be shown that these two parameters are related to each other, with an increasing API content leading to a decreasing maximum applicable Toutlet (Tcritical). Drying above Tcritical always led to an alteration of the size characteristics of the API nanoparticles and thus to a non-redispersible product with respect to the defined quality criteria. For each proportion of API to matrix former, a Tcritical could be found. Tcritical showed a linear relation to the API content. The linear regression of this relation was defined as process boundary. The y-intercept of the process boundary correlated well with the glass transition temperature (Tg) of the pure matrix former used for spray drying. The two APIs under investigation led to virtually identical behaviour if other parameters were kept constant. The particle size of the initial nanosuspension had an important influence. Nanosuspensions with comparatively small particle sizes led to a significantly stronger decrease of the process boundaries compared to the use of larger particle sizes. The maximum API content that leads to a redispersible product is thus decisively determined by Toulet of the spray dryer, Tg as well as the proportion of the matrix former and by the particle size of the API nanoparticles used.

Controlled agglomeration during spray drying offers several advantages for both powder manufacturers and consumers, and thus it is commonly implemented by industry. The implementation, however is largely based on experience, given the scarcity of comprehensive prediction tools. A resource-efficient approach to numerically treat agglomerates and yet provide an indication of their structures is desired to perform realistic simulations without the need for high-performance computing. In this work, a new numerical model for the treatment of coalescence and agglomeration was implemented and evaluated at two distinct scales with significantly different particle number densities within a Eulerian-Lagrangian CFD framework. The model could accurately predict the trends in the final particle size distributions and distinguish realistic agglomerate structures occurring under different conditions. Challenges were encountered as a result of how the underlying collision detection routine handles high particle number density. Several strategies are proposed to overcome these challenges. This work constitutes significant progress towards achieving an efficient prediction tool to estimate final powder properties and will prove useful in performing large-scale simulations to design and control agglomeration.

The aim of this study was to investigate the characteristics of the Fingered citron extract (FCE) microcapsules powders with different formulations of the encapsulation carrier agents [gum arabic (GA), maltodextrin (MD), modified starch (MS), and whey protein (WP)], which are obtained through spray drying. Encapsulation yield, encapsulation efficiency, moisture content, hygroscopicity, water activity, density properties, Carr's index, cohesiveness, flowability, porosity, wettability, solubility, color, particle size, thermal behavior, relative crystallinity, and micrographs were analyzed. Moreover, chemical structure of the microcapsule powder was identified using Fourier transform infrared spectroscopy (FT-IR). Best results were achieved when Fingered citron extract was encapsulated using gum arabic/maltodextrin/modified starch (GMS) formulation as carrier agents, where it had the highest encapsulation yield (89.39%) and encapsulation efficiency (87.20%). Furthermore, it achieved the best result in density properties, flowability, porosity, wettability, and relative crystallinity. These results have shown that using gum arabic/maltodextrin/modified starch formulation was superior for production of the Fingered citron extract microcapsules powders.

A spray drying technique was developed to prepare injectable and biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating a model luteinizing hormone-releasing hormone agonist (LHRHa)-based peptide, leuprolide. Various spray drying parameters were evaluated to prepare 1-month controlled release formulations with a similar composition to the commercial Lupron Depot® (LD). A single water-in-oil emulsion of aqueous leuprolide/gelatin solution in PLGA 75/25 acid capped (13 kDa Mw) dissolved in methylene chloride (DCM) was spray-dried before washing the microspheres in cold ddH2O and freeze-drying. The spray-drying microencapsulation was characterized by: particle size/distribution (span), morphology, drug/gelatin loading, encapsulation efficiency, and residual DCM and water content. Long-term release was tested over 9 weeks in PBS + 0.02% Tween 80 + 0.02% sodium azide pH 7.4 (PBST) at 37 °C. Several physical-chemical parameters were monitored simultaneously for selected formulations, including: water uptake, mass loss, dry and hydrated glass transition temperature, to help understand the related long-term release profiles and explore the underlying controlled-release mechanisms. Compared with the commercial LD microspheres, some of the in-house spray-dried microspheres presented highly similar or even improved long-term release profiles, providing viable long-acting release (LAR) alternatives to the LD. The in vitro release mechanism of the peptide was shown to be controlled either by kinetics of polymer mass loss or by a second process, hypothesized to involve peptide desorption from the polymer. These data indicate spray drying can be optimized to prepare commercially relevant PLGA microsphere formulations for delivery of peptides, including the LHRHa, leuprolide.

While nanoparticulate drugs for deep lung delivery hold promise for particular disease treatments, their size-related physical instability and tendency of being exhaled during breathing remain major challenges to their inhaled formulation development. Here we report a viable method for converting drug nanosuspensions into inhalable, stable and redispersible nano-agglomerates through combined in-situ thermal gelation and spray drying. Itraconazole (ITZ) nanosuspensions were prepared by flash nanoprecipitation, and co-spray dried with two different grades of the gel-forming polymer, methylcellulose (MC M20 and MC M450) as protectants. MC M20 was found superior in protecting ITZ nanoparticles against thermal stress (through nanoparticle entrapment within its gel network structure) during spray drying. In terms of redispersibility, an Sf/Si ratio (i.e., ratio of nanoparticle sizes after and before spray drying) of unity (1.02 ± 0.03), reflecting full particle size preservation, was achieved by optimizing the suspending medium content and spray drying parameters. Formulation components, nanosuspension concentration and spray drying parameters all showed a significant impact on the aerosol performance of the resulting agglomerates, but an absence of defined trends or correlations. Overall, the MC-protected nano-agglomerates displayed excellent in-vitro aerosol performance with fine particle fractions higher than 50% and mass median aerodynamic diameters within the 2-3 µm range, which are ideal for deep lung delivery.

Development of spray drying of biomolecules has proved challenging primarily due to protein instability caused by high drying temperatures and atomization process. This study suggests a two-step approach towards a better understanding of spray drying process of large biomolecules. Using lysozyme as a model biomolecule a full factorial Design of Experiments (DoE) was employed to define the most critical process and formulation parameters. With respect to parameters such as feed rate, outlet temperature (Tout) and feed solid concentration, Tout was determined to be the most significant factor affecting the enzymatic activity. Forced deactivation studies were performed to identify critical points of potential enzymatic degradation during the drying process. Results show that lysozyme in solid form significantly inactivated when heated up to temperatures similar to Tout (70–90 °C). The approaches presented herein provide an improved understanding of the critical process and formulation parameters required for the successful spray drying of biomolecules.

In this study, oil palm milk was spray dried to produce palm milk powder in order to prolong the shelf life and easy storage. The objective of this research was to determine the effect of spray drying parameters on palm milk powder properties, which were inlet temperatures (120 °C, 140 °C, and 160 °C), feed flow rates (5 mL/min, 7 mL/min, and 14 mL/min), and ratio of additive (maltodextrin) to oil palm milk. Based on the powder yield, the optimum conditions for oil palm milk powder production was determined. Moisture content, fat content, solubility in water, flowability of powder, and hygroscopicity were analysed for the powder samples. Powders produced at the highest inlet temperature show the lowest moisture and fat contents. Inversely, the moisture and fat contents were the highest at the highest feed flow rate. However, the moisture content was the lowest and fat content was the highest at the highest ratio of maltodextrin to oil palm milk. The powder were easily soluble in water as shown by the time taken to dissolve varies between 8 and 24 s. Based on Hausner ratio, the palm milk powder was categorised as low cohesiveness which match to good flowability as indicated by Carr’s Index. The powder achieved non-hygroscopic state when it was produced with the highest ratio of maltodextrin to oil palm milk. The optimum spray drying conditions was at 160 °C for inlet temperature and 7 mL/min for flow rate and 9% (w/v) of maltodextrin for percentage ratio of maltodextrin with the highest powder yield obtained was 45%.

Owing to its high theoretical capacity, P2-type Na2/3Fe1/2Mn1/2O2 has been considered as a kind of promising cathode material. However, the practical application is limited due to excessively high calcining temperature during traditional preparation processes. Here, we report the synthesis of P2-Na2/3Fe1/2Mn1/2O2 by using a facile spray-drying method followed by calcining at low temperature. Under the optimal conditions, the well-crystallized P2-Na2/3Fe1/2Mn1/2O2 material with excellent rate capability and cycle ability is obtained. And the sample exhibits the initial discharge capacities of 217.9, 171.3 and 117.4 mAh g−1 at 0.1 C, 0.5 C and 2 C rate, respectively. The developed Na2/3Fe1/2Mn1/2O2 material, synthesized by a new spray drying-calcining procedure, may potentially be used as a suitable cathode in sodium ion batteries.

Spray drying is commonly used to manufacture food and dairy powders at industrial scale. Bioactive peptides, as hydrolysis products from various food proteins, are gaining interest due to their biological functionality including immunomodulation, antimicrobial, and antioxidant properties. This article reviews several bioactive peptides/hydrolysates from different food sources, focusing on their processing and final powder characteristics. Additionally, we propose a strategy for encapsulation of food peptide/hydrolysate via spray drying. The identification of suitable drying parameters and/or formulation could help overcome the limitations associated with the current processing of food peptides.

Developing strategies for the production of porous particles with controllable structures using a spray-drying method has attracted attention of researchers for decades. Although many papers have reported their successful production of porous particles using this method, information on how to create and control the porous structures as well as what parameters involving and what formation mechanism occurring during the synthesis process are still not clear. To meet these demands, the present review covers strategies in the spray-drying developments for the fabrication of porous particles with controllable structure. This information is important for optimizing the production of porous particles with desirable properties. Regulation of process conditions and precursor formulations are also explained, including composition, type, and physicochemical properties of droplet and raw components used (i.e., host component, template, and solvent). The electrostatic interactions between the individual components and the droplets are also presented, while this information tends to be neglected in the conventional spray-drying process. To clarify how the porous particles are designed, current experimental results completed with illustrations for the proposal particle formation mechanism are presented. The review also completed with the opportunities and potential roles of the changing porous structures in practical uses. This review would provide information on how to produce porous particles that can be used for advanced functional materials, such as catalysts, adsorbents, and sensors.

International audience; The effects of two pretreatments (microwaves or oven-drying) on the dogfish (Squalus acanthias) skin as well as two drying processes (freeze-drying or spray-drying) on the extracted gelatins were studied. Thus six types of gelatins were obtained, three of which were freeze-dried (FG) and the others were spray-dried (SG), from the untreated skin (US), microwaves-pretreated skin (MS) and oven-pretreated skin (OS). The highest yield (8.67%) was obtained for the OSFG, while the lowest one (3.06%) was measured for the OSSG. Interestingly, all gelatins exhibited relatively high protein (84.02-89.53%), and low lipid (0.50-1.71%) and ash (3.05-7.17%) contents. In addition, gelatins were analyzed by the Fourier transform infrared and the spectra displayed important differences in some specific peaks, particularly in the amide I, amide II and amide III. The gelatins extracted from the untreated skin, regardless the drying method, presented the highest foaming capacity. The textural profile analysis showed that USSG was the hardest (213.6 g) and the chewier (23.8 N × mm) gelatin. Moreover, analysis of thermal properties showed that USSG also has the highest glass-transition temperature. The interesting properties of gelatin extracted from dogfish skin encourage their future use as a functional ingredient in industrial food formulations.

A facile synergetic strategy is reported for the synthesis of the LiMnO2@VXC-72R composite microspheres by applying spray-drying technique with nanosized LiMnO2 particles as host material and conductive carbon black (VXC-72R) as dispersing agent. In this hybrid structure, LiMnO2 nanoparticles promote the lithium-ion diffusion due to the nanosized diffusion distance, whereas well-distributed VXC-72R suppress the aggregation of LiMnO2 nanoparticles and enhance the electronic conduction. Moreover, the micro-sized spherical morphology with low specific surface area is conducive to reducing the contact area between electrolyte and composite cathode, which inhibit the manganese dissolution. Benefiting from their synergistic effect, the LiMnO2@VXC-72R composite microspheres achieve the maximum discharge capacity of 187.3 mAh g−1 with good cycling stability at 0.1 C. After 50 cycles, the discharge capacity of composite cathode is still maintained at 173.2 mAh g−1, which is significantly higher compared to the primary LiMnO2 particles. Moreover, the LiMnO2@VXC-72R composite microspheres exhibit outstanding rate performance with high discharge capacity.

The objectives of the current work were (a) to investigate the suitability of soluplus®, a hydrophilic polymer, as a carrier for the entrapment of curcumin (CUR) SEDDS by the spray-drying process, and (b) to compare soluplus® with neusilin® US2, a hydrophobic high-capacity adsorbent for solid SEDDS. Both carriers produced free flowing powders with high CUR entrapment efficiency. When filled into capsules, approximately 95% of CUR was dissolved from the soluplus® powder within 120 min and only 41% from the neusilin® US2 base powder. When the powders were compressed into tablets, a slow CUR release was observed over 24 h, which varied as a function of compression force and the percentage of disintegrant used. In conclusion, current study demonstrated the feasibility of using soluplus® as a carrier for the preparation of solid SEDDS with more favorable release profiles when compared to the conventional hydrophobic adsorbents.

It is a challenge to develop a facile and scaleable approach to boost the application of high-energy fluorinated iron/manganese phosphate cathode materials for sodium-ions batteries. In this study, for the first time, the porous Na2Fe1-xMnxPO4F/C (x = 0.2, 0.4, 0.6, 0.8) nanocomposites are successfully designed via spray drying, following in-situ pyrolytic carbonization process. To examine this synergetic design, the rate capability, cycling stability, and reaction kinetics of the cathode materials are investigated in detail. It is found that the solid solution Na2Fe0.6Mn0.4PO4F/C cathode delivers the high discharge capacities of 94.8 and 30.0 mAh g−1 at 0.05 C and 1.0 C, respectively, and a reversible capacity of 51.0 mAh g−1 after 100 cycles at 0.2 C with a capacity retention of 89.3%. Particularly, the cycling stability as well as rate capability of Na2Fe0.6Mn0.4PO4F/C are superior to those of the other Na2Fe1-xMnxPO4F/C solid solutions and the two-phase mixture of Na2MnPO4F/C and Na2FePO4F/C. Furthermore, the potential strategies to further improve the electrochemical performance of Na2Fe0.6Mn0.4PO4F/C cathode are proposed based on the kinetics analysis of its electrochemical impedance spectroscopy spectra at various charge/discharge depths. It is expected that our research strategies and findings can be extended to other electrode materials in Li+/Na+ storage and beyond.

In this study, sour cherry seed oil (SCSO) loaded gum Arabic (GA)-Maltodextrin (MD) microcapsules were developed by using spray-drying technique. The optimum processing conditions determined using the response surface methodology (RSM) were as follows: a weight ratio of GA to MD (GA:MD composition) of 1:11, a weight ratio of oil to total solid (core-wall ratio) of 20%, and inlet temperature of 195 °C. SCSO powder (SCSOP) was characterized in terms of morphology and size using scanning electron microscopy (SEM), and a laser particle diameter analyzer. The presence of SCSO in GA/MD matrix was confirmed by using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The thermal stability of the SCSOP was assessed using thermogravimetric (TGA) and differential thermal analysis (DTA). Microencapsulation provided a remarkable oxidative stability to SCSOP compared to free sour cherry oil. The antimicrobial potential of the microcapsules were assessed against pathogenic bacteria, yeast and mold.

Application behavior of spray dried powders such as reconstitution behavior and flowability is indirectly influenced by powder particle morphology. We here investigated the influence of the drying conditions and composition for whey protein (WP), maltodextrin (MD) and their mixtures on particle morphology during pilot-scale spray drying. Even though all powders showed a variety of morphologies, MD powders contained more wrinkled particles and had high bulk density, whereas pure WP powders contained more hollow particles. Mixture powders (75:25 WP:MD) show more hollow particles with increasing inlet temperature, with a lower bulk density. The observed morphologies for different formulations corresponded roughly to previous observations during sessile single droplet drying, but the results indicate that the morphology is also influenced by the faster pilot-scale drying, which was not evident in the slower single droplet drying.

This paper reports the synthesis of LiNi0.8Co0.15Al0.05O2 (NCA) cathode powders using a simple flame assisted spray pyrolysis (FSP) and a spray drying (SD) processes, in which metal salt precursors dissolved in glycerol were used for spraying. X-ray diffraction confirms that the NCA powders have a layered structure, with a low order of cationic mixing. Electron microscopy shows that the particles produced by FSP have a relatively smaller size and a smoother surface than that produced by SD. The NCA powder from the FSP process has an initial discharge capacity of 200.2 mAh/g in voltage range of 3.0–4.3 V at 0.1C. It shows very good capacity retention of 91.5% at 1C and 89.4% at 5C after 200 cycles. These results demonstrate that glycerol can replace water and be used as a solvent in spray processes to make cathode powders, promising a new environmentally-friendly synthesis route for battery powder materials production.

This study investigated the microencapsulation of fermented noni juice (FNJ) via a novel pilot scale micro-fluidic-jet-spray-dryer (MFJSD). Different concentrations of maltodextrin (M1, 10–13 DE; M3, 17–20 DE) and gum acacia (GA) were used as wall materials. The physicochemical properties, microstructure, droplet-to-particle formation process and bioactives stability of the powders produced by the MFJSD were examined. Results showed that the M1 powders with 28% solid content (M1, 28%) exhibited better bulk density, particle size, glass transition temperature and hygroscopicity than the other three powders produced (namely the M1 (21%), M3 (28%) and GA (21%) powders). The FNJ powders underwent five different stages during the drying process, from isotropical drying, crust formation, solidification and buckling to final particle formation. The external surface morphology of the powders was obviously influenced by the wall materials selected. However, the drying and wall material type have limited effect on the stability of bioactives in the FNJ powders after microencapsulation and during storage. This study provided insight into the micro-fluidic-jet spray drying of FNJ, and evaluated the properties and stabilities of the powders produced.

Anchovy oil was successfully encapsulated into multi-core microcapsule powder using a two-step microencapsulation method. The inner and outer shells of the microcapsules were created separately using gelatin-SHMP complex coacervates as shell materials. Fucoidan extract was used to crosslink these complex coacervates shells of microcapsules before spray drying. The spray dried microcapsules produced using the two-step method exhibited high encapsulation efficiency (99.83%), low surface oil content (0.10%), high oil payload (55.68%) and significantly improved oxidative stability. The formation of the outer shell during the second cooling step of two-step microencapsulation method significantly improved the oxidative stability of the anchovy oil by smoothing the surface of the microcapsules.

The main goal of this work was to assess if the Supercritical CO2-Assisted Spray Drying (SASD) is a competitive technology for the production of inhalable trehalose and leucine composite particles with advantageous properties and aerodynamic performance while ensuring a high process throughput and yield. For that purpose, a systematic Quality-by-Design approach using the design of experiments tool, followed by a statistical analysis were implemented. A full-factorial design was used to assess the impact of the static mixer pressure, inlet drying gas temperature and feed flowrate on the powder physical properties and in vitro aerodynamic performance. The powders were produced through SASD with yields up to 70%, while enabling the optimization of the overall throughput. Improved in-vitro aerodynamic performance was driven by the successful manipulation of the process parameters, namely by decreasing the feed flowrate and increasing the inlet drying temperature, yielding powders with fine particle fraction values up to 86%.

The formulation of bioactive powders is crucial to their property, functionality and bioaccessibility. This study investigated the incorporation of Ca2+ as a protectant aid for producing active dry probiotics via spray drying, and explored the mechanism underlying the positive effect of Ca2+ on cell viability. At inlet temperature of 98 °C and outlet temperature of 65 °C, supplementing 1 mM CaCl2 to either 10 wt% lactose or 10 wt% trehalose solution increased the survival ratio of Lactobacillus rhamnosus GG (LGG) from 5% to 30%. The growth capability of dried LGG was also enhanced in the presence of calcium. Powder properties including particle morphology, amorphous state and infrared spectrum were minimally influenced at such a low Ca2+ loading. By contrast, adding 1 or 100 mM Ca2+ in reconstitution solution or MRS agar plates notably improved the survival of LGG cells during single droplet drying with pure lactose protectant. The findings suggested that the protective mechanism of Ca2+ is based on enhancing the intrinsic tolerance of LGG cells, rather than modifying the powder properties. Given the protective effect of Ca2+ on probiotic cells under stressful conditions, calcium-containing dry probiotic products that confer duel benefits to consumers may be developed as new types of functional foods.

The encapsulation of phase change materials (PCM) is the essential step to make PCM easily utilizable. Aiming for a feasible process on a large scale, the combination of PCM/sol-gel emulsion and the spray-dry process was employed for the production of PCM encapsulated in silica shell matrices. Two PCMs, methyl palmitate and n-octadecane, with operating temperature appropriated for thermal comfort in trocical countries were selected. The composition of emulsion, i.e. tetraethyl orthosilicate (TEOS), cetyl trimethyl ammonium bromide (CTAB), and n-octadecane or methyl palmitate, was varied to find the optimal conditions for encapsulation. The influence of composition and process time on PCM's emulsion stability, size and structure of microcapsules, and encapsulation efficiency were investigated. The results showed that the optimal PCM to silica ratio was determined by the maximum quantity that could maintain the rigidity of the microcapsule structure. The low surfactant concentration that could still sustain emulsion stability contributed to improved encapsulation efficiency.

In this research, date powder was produced by drying aids including Tween 80, pectin, and whey protein concentrate (WPC) at different pH values (5.0, 6.5, 8.0, and 9.5) and using a spray drier at different temperatures (160, 170, 180, and 190 °C); then moisture content, solubility, hygroscopicity, bulk density, and total phenolic compounds (TPC) were determined and their correlation with structural characteristics of date powder was analyzed by Taguchi method. Interactions of pectin-surfactant, and pectin-WPC were more effective on moisture and bulk density of date powder, respectively. Although hygroscopicity of different treatments was in narrow range of 25–29%, temperature had the highest impact on TPC; beyond 170 °C, TPC of date powder decreased. Treatment No. 7, with the highest WPC level and pH values of 5, maintained the highest TPC content (701 mg 100 g−1) in date powder. SEM images revealed that pH = 9.5 and lower temperatures led to smaller particles.

The nanopowders of zirconia toughened alumina (ZTA) as soft spherical granules were directly synthesized by combining co-precipitation with spray drying (CPSD). The co-precipitation of alumina (Al2O3) and yttria-stabilized zirconia (YSZ) was performed together in one step to obtain the ZTA precipitate. Spray drying, which is the most preferred industrial processing way to produce the nanopowders as spherical granules, was used to atomize, dry and granulate the suspension like milk prepared from the synthesized ZTA precipitate under previously optimized spray drying conditions. However, the important and complex processing parameters of spray drying such as the solid-liquid ratio and the feeding rate of the suspension, the inlet temperature and the flow rate of the hot air have to be optimized depending on the moll mass and volume of the component in the prepared suspension. The ZTA nanopowders containing 4–20 wt% YSZ synthesized by the CPSD method have a crystalline structure of alumina and YSZ, an average nanoparticle size between 26.64 and 46.70 nm with a very high specific surface area (SSA) between 77.43 and 112.41 m2 g−1 in a soft spherical granule form, which were determined by XRD, BET and SEM, respectively. The preparation and drying conditions of the synthesized precipitate, the solid-liquid ratio of the suspension and the molar mass ratio of YSZ in Al2O3 matrix have a significant effect on the crystallinity, morphology, particle size, SSA, and granule form of the synthesized ZTA nanopowders.

In India, groundnut is mainly used for oil extraction or consumed in roasted form prompting a need for diversification to further increase its value and utility. In the present study, spray drying of groundnut milk was carried out using three variables of spray dryer i.e., inlet air temperature (180–220 °C), atomization air pressure (2–3 bar), feed pump speed (24–36 rpm) using Box-Behnken design of Response Surface methodology. The moisture content of powder decreased with an increase in inlet air temperature and atomization air pressure. The bulk density increased with increase in atomization air pressure. Maximum dispersibility (98.48%) was observed at an atomization air pressure of 2.57 bar. The insolubility index of the powder increased and lightness value (L*) decreased with an increase in inlet air temperature. The optimized conditions for spray drying of groundnut milk were inlet air temperature: 186 °C, atomizing air pressure: 2.5 bar and feed pump speed: 27 rpm.

Hypothesis Spray drying is a facile technique to transform colloidal dispersion into micro-granules of controlled size, shape, and morphology. There is significant interest to understand the structural integrity, different morphology of the granules obtained post spray drying which find potential application in many technological fields. The shape of the constituent particles in the colloidal dispersion that is spray dried is expected to influence the micro-structural features of the micro-granules. Experiments We investigate the formation of micro-granules consisting of nano-ellipsoids through controlled spray drying. The morphological features and the packing of ellipsoids in the granules are quantitatively analyzed by using small angle neutron scattering, small angle X-ray scattering and high-resolution field emission scanning electron microscopy. The time evolution of the micro-structure and the structural integrity of the granules are investigated by re-dispersing the powder granules in water. Findings The morphology of the granules are found to be strongly correlated with the aspect ratio of the ellipsoid. While the drying of droplets containing lower aspect ratio ellipsoids give rise to mostly spherical granules, in stark contrast, for higher aspect ratio ellipsoids, micro-granules of different morphologies are formed including doughnut shaped granules. A plausible mechanism explaining such an aspect ratio dependent shape transformation is proposed.

Improvements in the membrane separation of whey and subsequent spray drying for the recovery of Whey Protein Concentrate (WPC) have been investigated in the present work. Initially, ultrasonic pretreatment of whey was performed to reduce the microbial contamination and possibly improve the membrane separation based on inducing changes in the whey proteins. Studies involving the effect of important parameters in the membrane operation such as transmembrane pressure (TMP), type of membrane and molecular weight cutoff (MWCO) on permeate flux established that 10 kDa hydrosart membrane gives maximum permeate flux with minimum fouling at an optimum TMP of 1.2 bar. Studies with ultrasound assisted ultrafiltration established that the fouling was reduced with ultrasound also giving higher permeate flux. Effect of spray drying parameters such as air pressure, aspirator rate (rpm), feed flow rate and dilution on the WPC yield, analysed using SDS-PAGE and Kjeldahl method, has also been investigated. Additionally, the use of ultrasonic nozzle in the spray drying was investigated and the results were compared with pneumatic nozzle. Overall, it was clearly established that pretreatment, membrane characteristics, ultrafiltration operating parameters and spray drying parameters play an important role in deciding the WPC recovery from whey. Significant process intensification benefits were demonstrated to be obtained with the use of ultrasound both in membrane separation and spray drying.

Spray drying is a well-established technology to produce inhalable dry powders. However, the amorphous nature of the particles typically obtained from the process can lead to physically and chemically unstable products. The purpose of this study was to investigate whether spray-drying could be used as a manufacturing method to produce co-amorphous drug amino acid powders with high physical stability and inhalable particulate properties. Budesonide (BUD), a compound for the treatment of lung inflammation, was co-spray-dried at a 1:1 M ratio with arginine (ARG) to produce co-amorphous powders. Two experimental factors, the solid concentration (0.85, 1.00 and 1.13%, w/v) and the ethanol concentration (55 and 75%, v/v) of the feed solution were varied to investigate the formation of co-amorphous BUD-ARG. X-ray powder diffraction (XRPD), modulated temperature differential scanning calorimetry (mDSC) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were used for solid state characterization. The particle morphology, the median mass aerodynamic diameter and the aerodynamic properties of the resulting co-amorphous powders were investigated using scanning electron microscopy (SEM), an aerodynamic particle sizer (APS), and a next generation impactor (NGI), respectively. Furthermore, the physical stability of the obtained dry powder was examined. The co-spray-dried BUD-ARG samples prepared within the experimental range were predominantly amorphous. However, it was observed that while using the feed solution with both high solid and ethanol concentrations, some residual crystallinity related to budesonide was observed. The formation of co-amorphous BUD-ARG, rather than two separate amorphous phases, was confirmed by mDSC analyses. In addition, FTIR analyses indicated that hydrogen bonding occurs between the carbonyl groups of BUD and the amide groups of ARG in the co-amorphous BUD-ARG mixtures. The NGI results indicated that the particulate properties of the co-spray-dried co-amorphous BUD-ARG were at an inhalable range, with emitted doses >80%, and fine particle fractions >50%. In addition, the co-amorphous BUD-ARG was more physically stable than spray-dried BUD when stored at room temperature under dry conditions. This study demonstrated that spray drying is a useful manufacturing approach to produce physically stable co-amorphous dry powders for inhalation purposes.

Absorption enhancers are often a major component of solid oral peptide formulations as compared to the active pharmaceutical ingredient and excipients. This commonly results in poor tabletability that is hard to mitigate in direct compaction by addition of small amounts of excipients. To improve the tabletability of bulky absorption enhancers, the model absorption enhancers, sodium cholate and deoxycholic acid, were co-spray-dried with hydroxypropyl methylcellulose E5, where the percentage of absorption enhancers was not lower than 90% (w/w). The physicochemical properties of the resulting powders were assessed by laser diffraction, scanning electron microscopy, X-ray powder diffraction, thermogravimetric analysis, and differential scanning calorimetry. The powders were compressed into tablets, and the tabletability was evaluated. Co-spray drying with 10% of hydroxypropyl methylcellulose significantly improved the tabletability of the both absorption enhancers. Moreover, it was demonstrated that small particle size and amorphous state rather than high moisture content contributed to the improved tabletability of the spray-dried powders. The study suggests that spray drying technology can be promising to overcome the poor tabletability of oral peptide formulation consisting of large amounts of absorption enhancers.