Optimization of the spray-drying process for developing guava powder using response surface methodology

Microencapsulated Bilberry and Chokeberry Leaf Extracts with Potential Health Benefits

The aim of the research was to develop microencapsulated powders of bilberry and chokeberry extracts via the spray drying technique. Two biopolymers, pectin alone and in combination with HP-β-CD, were used to preserve the antioxidant, hypoglycemic, photoprotective, and antimicrobial bioactivity of the berry leaf extracts. Moreover, the formed powders were characterized in terms of technological, chemical, and several biological properties. The obtained micro-sized powders (mean average particle diameter from 3.83 to 5.94 µm) demonstrated a process yield of up to 73%. The added biopolymers improved the flowability and cohesive properties of the powders and increased their thermal stability to 170 °C. The total content of polyphenolics in the powders ranged from 323.35 to 367.76 mg GAE/g DW for bilberry and from 186.85 to 227.59 mg GAE/g DW for chokeberry powders; meanwhile, chlorogenic acid was the predominant compound in powders. All samples showed stronger α-glucosidase inhibitory activity (IC50 values ranged from 5.00 to 19.59 µg/mL) compared with the reference standard. The study confirmed that spray drying is a suitable method for the preservation of the polyphenolic-rich extracts, while the addition of carriers has a positive effect on the improvement of microencapsulated powders' properties.

Comparative Analysis of Concurrent (CC), Mixed Flow (MX), and Combined Spray Drying Configurations on the Physicochemical Characteristics of Satsuma Mandarin (Citrus unshiu) Juice Powders

Satsuma mandarins are good sources of vitamin C and can be used as raw materials to produce novel plant-based food ingredients including satsuma mandarin juice powders (SJP). Food powders produced via spray drying often show thermal degradation due to the drying conditions and high drying air temperatures. The aim of this study was to evaluate the effect of using different spray drying configurations, including concurrent (CC), mixed flow (MX), and combined (CC + MX), at two inlet air temperatures (160 and 180 °C) on the physicochemical properties of SJP. Remarkably, SJP produced using the CC spray drying configuration exhibited a higher vitamin C content (3.56-4.01 mg/g) and lower moisture levels (15.18-16.35 g/100 g) than powders produced via MX or CC + MX. The vitamin C content of MX and CC + MX powders ranged from 2.88 to 3.33 mg/g. Meanwhile, all SJP had water activity values below 0.19. Furthermore, MX powders displayed the largest mean particle sizes (D50) (8.69-8.83 µm), higher agglomeration, and a rapid dissolution. Despite these differences, all SJP variants exhibited consistent color, surface area, and pore volumes. Notably, powders dried at higher inlet air temperatures (180 °C) showed less vitamin C content and increased thermal damage when compared with powders dried at 160 °C inlet air temperature. This study demonstrated the feasibility of producing high-quality SJP with an extended shelf life. SJP can be used as a novel plant-based ingredient in different food applications.

Optimization of spray drying process of Japanese apricot (Prunus mume Sieb. et Zucc.) juice powder using nondigestible maltodextrin by response surface methodology (RSM)

The optimal spray-drying conditions for manufacturing Japanese apricot (Prunus mume Sieb. et Zucc.) juice powder (JAJP) using response surface methodology (RSM) were investigated. The optimization was performed using two independent factors, which are inlet air temperature (130-180 °C) and different concentrations of nondigestible maltodextrin (NMD) as a carrier agent (10-30%). Responses such as drying yield, moisture content, water solubility index (WSI), bulk density, color, pH, and antioxidant activities of JAJP were investigated. Moisture content, vitamin C content, color, antioxidant activity, pH and bulk density were greatly influenced by inlet air temperature, but dry yield and WSI were only significantly affected by NMD concentration. The optimum spray drying conditions were determined as 14.7% NMD concentration and 154.5 °C inlet air temperature, respectively. At these optimum conditions, a drying yield of 55.73%, 4.84% moisture content, 90.98% WSI, 0.59 g/mL of bulk density, and 169.87 mg/g vitamin C content in JAJP were measured. Therefore, JAJP with the desirable physicochemical properties could be produced.

Optimization of spray drying process parameters for the food bioactive ingredients

Spray drying (SD) is one of the most important thermal processes used to produce different powders and encapsulated materials. During this process, quality degradation might happen. The main objective of applying optimization methods in SD processes is maximizing the final nutritional quality of the product besides sensory attributes. Optimization regarding economic issues might be also performed. Applying optimization approaches in line with mathematical models to predict product changes during thermal processes such as SD can be a promising method to enhance the quality of final products. In this review, the application of the response surface methodology (RSM), as the most widely used approach, is introduced along with other optimization techniques such as factorial, Taguchi, and some artificial intelligence-based methods like artificial neural networks (ANN), genetic algorithms (GA), Fuzzy logic, and adaptive neuro-fuzzy inference system (ANFIS). Also, probabilistic methods such as Monte Carlo are briefly introduced. Some recent case studies regarding the implementation of these methods in SD processes are also exemplified and discussed.

Lactic Acid Bacteria Simultaneously Encapsulate Diverse Bioactive Compounds from a Fruit Extract and Enhance Thermal Stability

This study develops an innovative cell-based carrier to simultaneously encapsulate multiple phytochemicals from a complex plant source. Muscadine grapes (MG) juice prepared from fresh fruit was used as a model juice. After incubation with inactivated bacterial cells, 66.97% of the total anthocyanins, and 72.67% of the total antioxidant compounds were encapsulated in the cells from MG juice. Confocal images illustrated a uniform localization of the encapsulated material in the cells. The spectral emission scans indicated the presence of a diverse class of phenolic compounds, which was characterized using high-performance liquid chromatography (HPLC). Using HPLC, diverse phytochemical compound classes were analyzed, including flavanols, phenolic acid, hydroxycinnamic acid, flavonols, and polymeric polyphenols. The analysis validated that the cell carrier could encapsulate a complex profile of bioactive compounds from fruit juice, and the encapsulated content and efficiencies varied by the chemical class and compound. In addition, after the heat treatment at 90 °C for 60 min, >87% total antioxidant capacity and 90% anthocyanin content were recovered from the encapsulated MG. In summary, these results highlight the significant potential of a selected bacterial strain for simultaneous encapsulation of diverse phenolic compounds from fruit juice and improving their process stability.

Effects of spray-drying parameters on physicochemical properties of powdered fruits

This review features different powdered fruits with optimal storage stability and physiochemical parameters. Spray-drying parameters, such as temperatures and flow rate, can affect the physical properties of powders. Carrier agents provide powders with various favorable qualities, e.g. good flow rate. Commercial spray-drying of fruit juice knows different carrier agents. The review involved scientific and methodological publications, conference papers, patents, regulatory papers, and Internet resources. They were subjected to grouping, categorization, comparative analysis, and consolidation. Inlet temperature, maltodextrin concentration, and air flow rate of spray-drying increased the powder yield but decreased the moisture content. Inlet temperature, maltodextrin concentration, and feed flow rate affected the solubility. Effects of atomization rate, air flow rate and free flow rate were assessed in terms of yield, moisture content, hygroscopicity, and solubility. The article introduces the fundamentals of spray-drying and describes the effect of each spray-drying parameter on the powder quality. The list of parameters included inlet air temperature, atomization rate, air flow, and feed flow rate. We also evaluated the impacts of various carrier agents on the powder quality. The article contributed to a better understanding of how variable parameters affect the quality of food powders. The results provide the food industry with better choice options to adopt certain parameters for specific production needs.

Predicting the Invasion Risk by Anastrepha sororcula (Diptera: Tephritidae) in Distinct Geographic Regions

The movement of endemic fruit flies to new habitats represents a major biological and economic threat. Anastrepha sororcula Zucchi, 1979 is widely distributed in Brazil and also in Colombia, Ecuador, and Paraguay. Here, we present the potential distribution of A. sororcula in endemic areas and project this model into other regions such as part of sub-Saharan Africa, Central America, and Asia to show areas around the world that this species can potentially establish. We combined geographic coordinates with climate data. The models were built using the maximum entropy (MaxEnt) algorithm. Many mango- and guava-producing countries exhibited climatic suitability for A. sororcula in the regions studied including the nine largest world producers: India, Brazil, Malawi, Kenya, Haiti, Cuba, Colombia, Madagascar, and the Democratic Republic of the Congo. Many of these countries showed ideal host plant availability and climatic conditions for the entry and establishment of A. sororcula. This study is a pioneer in the identification of representative areas in the world with climatic suitability for A. sororcula, which shows the importance of predicting areas at risk of invasion to monitor the movement and establishment of fruit fly species in new regions, which is fundamental to area-wide integrated pest management programs.

Sustainable food processing of selected North American native berries to support agroforestry

Chokeberries, elderberries, blueberries, and blackberries are highly nutritious native fruits in the US Midwest region. Their high moisture content, delicate structure easily leads to fruit loss/waste. This review focuses on different drying methods for whole fruits and juices to preserve their quality and improve their shelf life. Solar drying, hot-air drying, spray drying, freeze-drying, vacuum-drying, electromagnetic drying, and osmotic dehydration are the commonly used dehydrating methods for berries. Berries are photo, heat-sensitive, and rich source of essential nutrients. Texture, flavor, color, water content, phytonutrients, physicochemical properties can be influenced by dryer and processing parameter selection. Drying is a complex dynamic process, due to structural differences among various foods, combined thermal and non-thermal techniques could improve fruit quality. Hence, knowledge of drying behavior and degradation kinetics is vital for optimizing the process parameters to enhance the fruit quality. Freeze drying and spray drying showed better preservation of nutrients. Existing research suggests that chokeberries (Aronia) are underutilized compared to blueberries and blackberries. Aronia fruit has a lot of potentials containing health-promoting compounds and is yet to be explored. Future research suggestions have been put forward for the efficient use of drying techniques and to improve the fruit quality.

Evaluation of physico-chemical properties of tomato powder produced by an optimized freeze drying process

In this study, the physico-chemical properties of tomato powder produced by an optimized freeze drying process (FDP) were evaluated. With the lycopene content as the dependent variable, the optimum FDP conditions (i.e., thermal cracking time of 62 s, ascorbic acid addition amount [0.13%], and particle size [Dv90] of 163 μm) were obtained through response surface methodology (RSM). The results showed that the content of lycopene in the prepared tomato powder was higher than that in two commercial products. Aldehydes were the main components among 25 kinds of aromatic substances detected in tomato powder. The values of a * and a */b *, the hydration properties including water holding capacity (WHC) and oil binding capacity (OBC), and the content of total acid, ascorbic acid, and soluble solids were improved compared to commercial spray dried and freeze dried samples. All the above results suggested that FDP was an adequate procedure for the production of high-quality tomato powder.

Optimization of spray drying process parameters for production of Japanese apricot (Prunus mume Sieb. et Zucc.) juice powder

Optimization of spray drying conditions namely inlet air temperature (IAT) and maltodextrin (MD) concentration was utilized by response surface methodology for Japanese apricot (Prunus mume Sieb. et Zucc.) juice powder (JAJP) manufacture. Drying yield, moisture content, water solubility index (WSI), bulk density, color, pH, total phenol content (TPC), total flavonoid content (TFC), vitamin C content, and DPPH radical-scavenging activity of juice powder were measured. Moisture content, vitamin C content, color, DPPH radical-scavenging activity, pH, and bulk density were greatly influenced by IAT, but drying yield, WSI, TPC, and TFC were only significantly affected by MD concentration. The spray drying condition was optimum at 10% MD concentration and 165.8 °C IAT. The properties of juice powder were 37.50% drying yield, 4.81% moisture content, 134.25 mg/g vitamin C content, 27.52% DPPH radical-scavenging activity, 2.78 pH, 89.15% WSI, 232.856 μg GAE/100 g TPC, 404.66 μg CE/100 g TFC, and 0.49 bulk density.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10068-021-00950-8.

Development of water spinach powder and its characterization

The study was performed on water spinach (Ipomea aquatica), a hidden gem with lots of nutritional attributes and medicinal properties. To check its feasibility as an ingredient in other food products and to know its nutritional attributes, powders were made by drying the leaves and stems of the plant using different drying techniques such as sun drying, freeze-drying, and tray drying. The physicochemical analysis of powder was done to get a comparative result, in which the freeze-dried powder showed the most significant result. The physicochemical analysis revealed that lyophilized water spinach powder has a good amount of carbohydrates (58.15%), ash (12.39%), protein (4.01%), and fat (4.46%) content. The powder also possessed a high antioxidant property of 77.25% and a total phenolic content of 32 µg/ ml. SEM and XRD results showed that the water spinach powder was amorphous in nature.

Process optimization of spray-dried Moldavian balm (Dracocephalum moldavica L.) extract powder

The present study was aimed to develop the powder from Moldavian balm extract using a spray dryer to preserve the valuable phytochemicals such as hydroxycinnamic acid and flavonoids. In order to produce optimum Moldavian balm spray-dried powder, response surface methodology was applied. The inlet air temperature (120-180°C), compressed airflow rate (5-10 L/min), and carriers' concentration (10%-30%) were kept as independent variables, while moisture content, drying performance, porosity, total phenol content, total flavonoid content, and antioxidant activity were selected as responses. The process was optimized with inlet air temperature of 140.36°C, compressed airflow rate of 9.13 L/min and carriers' concentration of 18%, resulting in powder with moisture content of 7.68%, drying performance of 62.52%, porosity of 76.4%, total phenol content of 6.295 mg GAE/g, total flavonoid content of 0.378 mg QUE/g, and antioxidant activity of 51.78%. The optimized process led to attain the powder having significantly better phytochemical properties compared with others.

Effect of Pre-treatment in Producing Pumpkin Powder Using Air Fryer and Its Application in 'Bingka' Baking

Pumpkin powder is one of the main pumpkin products with longer shelf life and it can act as a substitute for pumpkin flesh in different types of formulated foods. This work focused on producing pumpkin powder from different pumpkin parts and evaluating the effects of powder substitution on the physical properties of cake (bingka). Different parts of pumpkin (peeled, unpeeled, and skin) were pre-treated by soaking in limewater solution and then dried in an air fryer at the temperature of 80 °C, 120 min and air flow of 5.11 m/s. The fresh pumpkin (peeled and unpeeled-pumpkin) and pumpkin powder (peeled and unpeeled-pumpkin) were both used in the production of ‘bingka’ and the baking parameters were optimised. The selected temperatures for baking ‘bingka’ were in the range of 130–150 °C and the baking time was between 25 and 35 min. Baking temperature and time had a significant effect (p < 0.05) on moisture content and hardness, but are insignificant towards chewiness. The ‘bingka’ baked using peeled pumpkin at optimum baking temperature (130 °C) and time (25 min) had higher moisture content (45.92%) as compared to those baked using unpeeled pumpkin 43.47%, peeled pumpkin powder (44.23%) and unpeeled pumpkin powder (43.47%). It can be concluded that pumpkin powders can be used as a substitute for raw material by considering the moisture content, hardness and chewiness of the products.

Physicochemical Properties of Guava Snacks as Affected by Drying Technology

Guava is widely consumed because of its agro-industrial use, and its antioxidant properties attributed to vitamin C and carotenoids content. However, it has a short shelf life. Guava has been dried by atomization, fluidized bed, lyophilization (FD) and convective drying (CD). CD requires long operation times and the product characteristics are not desirable. In contrast, FD produces high quality products, but requires long processing times, high energy consumption and high operation costs. As an alternative, the Refractance Window® (RW) drying is relatively simple and cheap technique. The objective of this study was to compare the effect of CD, FD and RW techniques, on the moisture content, water activity, color, porosity, volume change, vitamin C and carotenoids content in guava samples. The samples dried by RW required less time to reduce the moisture content and exhibited smaller changes in color than CD or FD. There were greater losses of carotenoids and vitamin C when drying by CD whereas RW had similar losses than FD. Lyophilized products exhibited minor change in volume and greater porosity. RW results in better retention of properties, compared with other drying techniques. Based on this, RW is a promising technique for the development of guava snacks.

Impact of drying methods on composition and functional properties of date powder procured from different cultivars

The present study was designed to evaluate the effect of two different drying methods, that is, spray drying and oven drying on physicochemical and nutritional attributes of date flesh powder of dhakki, aseel, and rabi varieties. Date powders were prepared using mixture of maltodextrin and acacia gum (50:50) as drying aid at the rate of 0.4 kg per 1.0 kg of date fruits (dry weight basis). The oven-drying conditions were 60°C for 48 hr, whereas in spray drying, flow rate of 30 ml/min at 150°C was maintained. Date powder was obtained in both treatments from three varieties. Nutritional profile in all six powders was explored specifically with quantification of sugars using HPLC-RI, followed by physicochemical characterization. The total phenolic compounds, color (L*a*b* values), hygroscopicity, bulk density, wettability, solubility index, and glass transition temperatures (using differential scanning calorimetry, DSC), were determined for the date powders. The nutritional profile and total phenolic contents and sugars (sucrose, fructose, and glucose) were significantly different for the varieties, while treatments showed insignificant effect. The physicochemical characteristics of date powder varied significantly with respect to the date varieties. The colored values were affected due to treatments also, and the spray-dried powders showed better color values. The drying methods also showed effects in some parameters such as wettability time. Similarly, bulk density was different in both treatments for rabi and aseel. The glass transition temperatures were significantly varied in varieties due to difference in sugar contents, but within the treatments, they remain unaffected. The highest glass transition temperature of spray-dried rabi was 53.2 ± 1.31°C.

Optimization of infrared drying condition for whole duku fruit using response surface methodology

Duku (Lansium domesticum), tropical exotic fruit, was successfully preserved by drying using exposure to infrared radiation emitters. Response surface methodology (RSM) is used to optimize independent variables (IRE distance of 6 cm and 10 cm, IRE temperature of 200 °C, 300 °C, 400 °C, and IRE exposure time of 50 s, 60 s, 70 s, and to produce response variables (weight loss, fruit firmness, titratable acidity, total soluble solid, and browning index).  It could be concluded from the optimization performed that drying duku skin in a whole fruit by exposing the fruit to the infrared emitter resulted in a duku fruit with a relatively good physical and chemical conditions and still be consumable. The IRE distance of 6 cm gave a desirability value of 0.80 while the IRE distance of 10 cm gave a desirability value of 0.92 however the IRE distance of6 cm gave a better storage time.  The IRE distance of 6 cm has an optimum value of weight loss 2.2%; optimum value of fruit firmness of 40.92 N; optimum value of total soluble solid of 17.48 brix; optimum value of titratable acidity of 0.33%; and optimum value of browning index of 0.9. The fitting model base on RSM resulted from this research indicated that this study could be used as the basis for alternative process in food processing of duku but still need further research to increase the shelf life and a better result in the chemical and physical characteristics of duku.

The Effect of Pretreatment (Spray Drying) on the Yield and Selected Nutritional Components of Whole Camel Milk Powder

The effect of spray drying on the composition of camel milk powder was evaluated. A full factorial experimental design was used to see the effects of inlet temperature (160 °C, 140 °C, and 120 °C), atomization pressure (800, 600, and 400 bar) and feed flow rate (5, 4, and 3 rev/s) on cyclone and vitamin C recoveries. Principal components analysis (PCA) was used to check classification of spray dried whole camel milk powders based on their processing conditions and multiple correspondence analysis (MCA) on the fatty acid profiles. The average proximate composition of the camel milk viz., fat, protein, lactose, and total solid were 3.0%, 3.21%, 3.01%, and 10.29% respectively. The powder yield (cyclone recovery) increased with increasing inlet temperature and decreasing feed flow rate. High outlet temperature and pressure decreased vitamin C recovery. As a result of PCA of the camel milk powders, they were classified into high heat treated and low heat treated milk powders while the MCA of the fatty acid profiles of camel milk powders were classified into high pressure and low pressure treated powders and it was concluded that higher atomization pressure caused increase in the content of fatty acids. PRACTICAL APPLICATION: Drying of camel milk (using spray drying) can extend its shelf life. The spray drying process must be optimized in order to retain the nutritional properties of the milk and the techno-functional characteristics of the powder. Here, the effect of the spray drying conditions on the yield and selected nutritional components of the milk powder was studied using a bench top spray dryer. However, there is need to translate these findings to an industrial volume dryer. These findings will play a big role in future spray drying operations since retention of important nutritional components is an important part of food processing.

Effect of different concentrations of pulverized mesocarp of Citrus paradisi Macf on the morphology and glass transition temperature of spray-dried lemon juice powder

The aim of this research was to evaluate the effect of different concentrations of pulverized mesocarp of Citrus paradisi Macf as a drying aid, on morphology, particle size and glass transition temperature of spray-dried lemon juice powder. Five concentrations of grapefruit mesocarp (0.4%, 0.8%, 1.2%, 1.6% and 2.0% (w/w)) and maltodextrin DE 10 (1.2%, w/w) were evaluated as encapsulant agents. The obtained data were evaluated by one-way ANOVA using Statistix version 8.0. For the means separation, the Tukey's test was applied with a 95% reliability. The morphology of the particles was described. According to the results, by applying different levels of coating agent in lemon juices, powder particles with different sizes (from 3.07 to 6.20 μm) and shapes (spherical, irregular and shrunken or reduced) are obtained; however, their glass transition temperature is not modified, finding values between 37.43 and 38.64°C.

Development of a NIR Method for the In-Line Quantification of the Total Polyphenolic Content: A Study Applied on Ajuga genevensis L. Dry Extract Obtained in a Fluid Bed Process

This study describes an innovative in-line near-infrared (NIR) process monitoring method for the quantification of the total polyphenolic content (TPC) of Ajuga genevensis dry extracts. The dry extract was obtained in a fluidized bed processor, by spraying and adsorbing a liquid extract onto an inert powder support. NIR spectra were recorded continuously during the extract’s spraying process. For the calibration of the in-line TPC quantification method, samples were collected during the entire process. The TPC of each sample was assessed spectroscopically, by applying a UV-Vis reference method. The obtained values were further used in order to develop a quality OPLS prediction model by correlating them with the corresponding NIR spectra. The final dry extract registered good flowability and compressibility properties, a concentration in active principles three times higher than the one of the liquid extract and an overall process yield of 85%. The average TPC’s recovery of the NIR in-line prediction method, compared with the reference UV-Vis one, was 98.7%, indicating a reliable monitoring method which provided accurate predictions of the TPC during the process, permitting a good process overview and enabling us to establish the process’s end point at the exact moment when the product reaches the desired TPC concentration.

Preparation and Characterization of Doripenem-Loaded Microparticles for Pulmonary Delivery

Background: Pneumonia is a bacterial lower respiratory tract infection that has a high morbidity rate. The gram-negative pathogen Pseudomonas aeruginosa is a significant cause of nosocomial infections and ventilator-associated pneumonias and is mainly treated by carbapenems. Doripenem is a carbapenem drug, which has a broad-spectrum antibacterial activity. The aim of this study was to develop doripenem-loaded chitosan microparticles for pulmonary administration to provide more efficient treatment for pneumonia. Methods: Ionotropic gelation and the spray-drying method were used to obtain doripenem-loaded chitosan microparticles with different lactose, trehalose, and L-leucine concentrations. Physicochemical characteristics, in vitro drug release properties, and aerodynamics properties were investigated and in vitro antimicrobial susceptibility tests of the formulations were performed. Assessment of aerodynamic properties of the powders, including Mass Median Aerodynamic Diameter, size distribution, and fine particle fraction (FPF), were performed using a Next Generation Impactor. Cytotoxicity of the fabricated microparticles was assessed using the Calu-3 cell airway epithelial cell line. Results: Optimum microparticles were produced using a combination of ionotropic gelation and spray-drying methods. Spray-dried microparticle production yield was relatively high (74.03% ± 3.88% to 98.23% ± 1.70%). Lactose, trehalose, and L-leucine were added to the formulation to prevent aggregation produced by the ionotropic gelation spray-drying method. Each formulation's encapsulation efficiency was above 78.98% ± 2.37%. The doripenem-loaded microparticle mean diameter ranged from 3.8 ± 0.110 to 6.9 ± 0.090 μm. Microparticles with 20% (w/w) L-leucine had the highest FPF ratio indicating the best aerosolization properties of the formulations. The efficacy of the formulations as an antibacterial agent was increased by forming doripenem-loaded microparticles compared to blank microparticles. P. aeruginosa showed the same susceptibility to all doripenem-loaded microparticle formulations. Cell viability of microparticles was between 70% ± 0.08% and 90% ± 0.04% at 0.5 and 10 mg/mL concentration, respectively. Conclusions: Doripenem-loaded microparticles, produced using a combination of ionotropic gelation and spray-drying methods, are suitable for pulmonary drug delivery based on their particles size, zeta potential, cytotoxicity and high production yield. To our knowledge, this is the first study that microparticles containing doripenem were produced and characterized.

Recent strategies in spray drying for the enhanced bioavailability of poorly water-soluble drugs

Poorly water-soluble drugs are a significant and ongoing issue for the pharmaceutical industry. An overview of recent developments for the preparation of spray-dried delivery systems is presented. Examples include amorphous solid dispersions, spray dried dispersions, microparticles, nanoparticles, surfactant systems and self-emulsifying drug delivery systems. Several aspects of formulation are considered, such as pre-screening, choosing excipient(s), the effect of polymer structure on performance, formulation optimisation, ternary dispersions, fixed-dose combinations, solvent selection and component miscibility. Process optimisation techniques including nozzle selection are discussed. Comparisons are drawn with other preparation techniques such as hot melt extrusion, freeze drying, milling, electro spinning and film casting. Novel analytical and dissolution techniques for the characterization of amorphous solid dispersions are included. Progress in understanding of amorphous supersaturation or recrystallisation from solution gathered from mechanistic studies is discussed. Aspects of powder flow and compression are considered in a section on downstream processing. Overall, spray drying has a bright future due to its versatility, efficiency and the driving force of poorly soluble drugs.