Morphology spray-dried powders

Spray drying 0.05 to 0.5 Low Morphology of spray dried powders can Instant foods, dyes, detergents, ceramics... 

Paramita V, lida K, Yoshii H, Furuta T. 2010. Effect of additives on the morphology of spray-dried powder. Drying Technology 28 323-329. 

Crystal Structure. Curdlan powder was the source of (l->- 3)- 6 -D-glucan uTed in our study since it is commercially available and has been demonstrated to be a linear chain constituted almost exclusively of (l->3)-3-D-glucose residues. The polysaccharide was obtaineci from Takeda Chemicals Company in Japan and its morphology has been previously described.(, 1J ) It is received as a spray-dried powder which is very poorly crystalline. 

To describe the particle formation process, several authors (Vehring 2008) emphasize the usefulness of the Peclet number (ratio between droplet evaporation rate and diffusional motion of the solutes) as a mean to predict the morphology of spray-dried powders. For low Peclet numbers, the diffusion motion of the solutes is fast compared to the velocity of the receding droplet surface and the droplet is allowed... 

Morphology of spray dried powders can vary widely... 

Fig. 6.12 CLSM pictures of the morphology and the arrangement of encapsulated flavor droplets in the spray-dried powder merges of transmitted images with (a) CLSM images for sodium fluorescence in green color and for Nile Red in red color, (b) He-Ne laser CLSM images...

The photos of Fig. 6.12 visualize in a non-destructive manner the distribution of emulsion flavor droplets (red color) over the cross-section of the spray-dried powder and the internal morphology of the product (i.e., the presence, or not, of a vacuole). Therefore, they show that the CLSM is a new valuable tool for studying and observing the encapsulated flavor. The technique can even be applied to study the release characteristics of flavor from the powder in real time (Yoshii et al., 2007). 

Powders intended for nasal administration have to be optimized in terms of particle size and morphology as these properties are related to potential irritation in the nasal cavity [23], Certain procedures (e.g., spray drying process) can modify the particle size of the drug powder raw material, but in order to optimize the morphology and flowability properties of some pure drug powders, excipients need to be used. Sacchetti et al. [28] reported that the use of mannitol as a filler and hydroxy-propylmethyl cellulose (HPMC) as a shaper of spray-dried caffeine microparticles modified the typical needle shape of spray-dried caffeine to a more convenient roundish shape. Further addition of polyethylene glycol (PEG) resulted in increased... 

The diameters of the particles, prepared from dispersion, are approximately 120 nm each. The powder morphology of spray-dried PMMA grafted siloxane particles is illustrated in Fig. 3a the spherical agglomerates are approximately 1-20 pm in size. The microstructure of the graft copolymer after processing is shown in Fig. 3b. 

Fig. 3a. Powder morphology (scanning electron micrograph) of spray-dried PMMA grafted siloxane particles (obtained from the dispersion of Fig. 2b)...

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