Microparticles production by a novel apparatus coupling ultrasonic atomization and microwave drying

Literature about microencapsulation apparatuses highlights several drawbacks for conventional processes, such as high energy consumption. The need arises to move towards optimization in pharmaceutical manufacturing, i.e. process intensification obtainable by alternative sources, such as ultrasound and microwave. Advantages of ultrasonic atomization are lower mechanical stress caused by vibration; avoided deactivation of bioactive substances; operation at low energy levels; lower velocity of droplets emerging from ultrasonic nozzles, that avoids, drying chambers with large size downstream and high pressures upstream (Rajan and Pandit, 2001). Peculiarity of microwave heating is that energy is directly delivered to materials through molecular interactions, i.e. by a loss mechanism, with electromagnetic field. High rates and energy conversion are expected, leading to several advantages over convective heating. This work presents a single-pot bench scale apparatus for shell-core microparticles production, exploiting these alternative resources with the aim of process intensification