Size Correlations Analysis of Polymeric Solution Microdroplets by Ultrasonic Atomization

The aim of this chapter is to show an application of size correlations analysis to predict polymeric solution droplets dimension starting from process parameters and material properties. Ultrasonic-assisted atomization, a mechanical approach to fragment liquid in fine spray, is adopted to produce the droplets. These latter are produced for microencapsulation purposes useful in pharmaceuticals productions. Interest in ultrasonic atomization technique is due to the advantages such as reduced energy request, reduced apparatuses size, low level of mechanical stress in materials and others, when comparing it to more conventional techniques. To this purpose a brief overview on spray techniques is presented as well as the basic principles of atomization. In particular, in this study the role of relevant parameters in atomization assisted by ultrasonics is discussed and correlations to predict droplets size are presented. Due to microencapsulation interest for pharmaceutical applications, alginate solution sprays are purposely produced and undergone to experimental (measurements) and theoretical (calculation) size observations. The possibility to use reliable empirical correlations is very useful due to the key role that the size of microdroplets plays when they are used in pharmaceutical production because size of drug carriers can influence the rate and duration of release of enclosed therapeutic agents.