A low-cost ultrasonic spray dryer to produce spherical microparticles from polymeric matrices

Abstract

Recebido em 5/4/06; aceito em 10/11/06; publicado na web em 29/8/07The spray-drying technique has been widely used for drying heat-sensitive foods, pharmaceuticals, and other substances, because it leads to rapid solvent evaporation from droplets. This method involves the transformation of a feed from a fluid state into a dried particulate, by spraying the feed into a hot medium. Despite being most often considered a dehydration process, spray drying can also be used as an encapsulation method. Therefore, this work proposes the use of a simple and low-cost ultrasonic spray dryer system to produce spherical microparticles. This equipment was successfully applied to the preparation of dextrin microspheres on a laboratory scale and for academic purposes.

Dextrin‐Microencapsulated Porphyrin: Luminescent Properties

“…The microencapsulation process was accomplished using a previously described ultrasonic spray‐dryer system ( 3). 24 In this process, micro‐ and nanodroplets from the feed solution were produced and dried inside a vertical tubular furnace. The inlet and outlet temperatures, 280°C and 275°C, respectively, for the drying chamber were chosen according to the polymer thermal features.…”

“…In this work we report the microencapsulation of the TPPS 4 photosensitizer in dextrin by an ultrasonic spray‐dryer developed by our group 24 . The encapsulated TPPS 4 was morphologically characterized by scanning electron microscopy (SEM), and its photophysical properties were studied and compared with those of a physical blend of dextrin and TPPS 4 .…”

“…Scheme of the cocurrent ultrasound spray-drying system 24. compared with those of a physical blend of dextrin and TPPS 4 .…”

Porous Carbon Produced in Air: Physicochemical Properties and Stem Cell Engineering

“…Aerosol materials synthesis methods1–9 have been utilized to prepare a distinct platform of spherical composite materials that incorporate sub‐100 nanometer features. Nanostructured microspheres (ns‐μS) and extended surfaces made up of metal, metal oxides and sulfides such as TiO 2 ,10–14 SiO 2 ,15–19 Co,20 Co 3 O 4 , CuO, NiO,21 ZrO 2 ,22 ZnO,23, 24 Al,25 Al 2 O 3 ,26 BiVO 4 ,27 MoS 2 ,28 ZnS,29, 30 as well as polymers31 and carbon32–35 have been prepared via ultrasonic spray pyrolysis (USP)7 methods using molecular precursors to give uniquely structured materials (Figure S1). Here, we report a new, simple and versatile synthetic route to high surface area carbon microspheres that have hierarchical, mesoporous structure ( Figure ); and, we report their physicochemical and biological properties.…”

The ultrasonic processing of dairy products – An overview

“…The two most common atomizing devices used in dairy applications are centrifugal (rotary) and pressure (nozzle) atomizers [25]. However, ultrasonic atomizers offer a viable alternative [58]. In this case, it is important to distinguish between ultrasonic nozzles that produce an aerosol by passing a liquid feed through a vibrating horn and ultrasonic nebulizers that operate at higher ultrasonic frequencies and generate a "fountain-like" structure in a thin liquid film.…”