Spray-drying process dispersions

The spray-drying process first requires the formation of a slurry to be sprayed, which can be a concentrated solution of the agent to be dried or a dispersion of the agent into a suitable nondissolving medium. The dispersion is then atomized into droplets, which are exposed to a heated atmosphere to effect the drying process. Completion of the process yields a dry, freeflowing powder that ordinarily consists of spherical... 

The loss of heat-sensitive material during the spray-drying process has led to a number of alternative methods for dehydration of sprayed microcapsules. Spray-cooling and spray-chilling are similar to spray-drying, where the core material is dispersed in a liquefied coating or wall material and atomized at low temperature. 

In the food industry, because the spray dryer is commonly available, economical, fast, and produces good-quality material [16], it becomes the most common means of encapsulation. The encapsulation process is simple and similar to the one-stage spray drying process. The coated material is called the active or core material, and the coating material is called the shell, wall material, carrier, or encapsulant [43]. The active material to be encapsulated, such as an oil or fia-vor in an oil base, is dispersed in a hydrocolloid carrier, e.g., gelatin, modified starch, dextrin or maltodextrin, or gum arabic. After the emulsifier is added, the mixture must be... 

In order to further understand the mechanism in this low-pressure environment, a sol precursor containing colloidal nanoparticles was also studied [22]. From the experimental results, dispersed nanoparticles could be obtained at a relatively low pressure (20 Torr). A possible mechanism for the sol-to-dry particle formation in the spray-drying process under low-pressure conditions was proposed based on the experimental results and available theories. Droplet breakup due to competition between osmotic and Laplace pressure, and particle fragmentation due to fast drying, were considered to be two major factors. 

Leane MM, Sinclair W, Qian F, Haddadin R, Brown A, Tobyn M, Dennis AB, (2013) Formulation and process design for a solid dosage form containing a spray-dried amorphous dispersion of ibipinabant. Phami Dev Technol 18 359-366... 

Material produced from spray-drying processes are generally spherical and hollow due to process in which the solution of dissolved drug and polymer are sprayed as fine droplets and then rapidly dried in an inert stream of warm air. Spray-dried dispersions are oftentimes porous and fragile due to the escape of solvent through the solid matrix. Processing factors that influence the particle properties of the spray-dried dispersion (drying temperature, spray rate, droplet size, air flow, etc.) will influence the dissolution rate. 

A. Patel, A. Agrawal, and R. Dave, Investigation of the effects of process variables on derived properties of spray dried solid-dispersions using polymer based response surface model and ensemble artificial neural network models, Eur. J. Pharm. Biopharm., 86,404-417,2014. 

The foam spray drying process was developed for dairy industry at the start of the twentieth century. The spray drying of foamed materials was patented in 1917 (Campbell, 1917) to dry foamed milk and egg albumin (Rath and Kudra, 2006), but some 40 years later Sinnamon et al. (1957) found that the vacuum drying of concentrated milk foam would produce a whole-milk powder of good flavor and dispersibility. Morgan et al. (1959) showed that the dispersibility of whole-milk powder could also be maintained in foamed products during drying at atmospheric pressure. 

The inhomogeneity of the spray distribution resulting from the atomization process has a strong influence on the spray drying process. The interaction of spray particles may strongly affect the evaporation process. The direct quadrature method of moments (DQMOM) to solve Williams spray equation has been developed by Marchisio and Fox [8]. This method has been applied to sprays by Fox et al. [9] for the first time, and it is suitable to model a poly-disperse droplet/particle flow and the related physical processes. DQMOM has been coupled... 

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