422 research outputs found
Analysis of dissolved-gas atomization: supercritical CO2 dissolved in water
Supercritical dissolved-gas atomization is an atomization process in which carbon dioxide at temperature and
pressure above its critical point is used as the atomizing gas. The spray characteristics in terms of droplets
size and distribution have been experimentally studied using a laser diffraction method based on a Malvern
apparatus. The main parameter that influences the droplets size is the gas-to-liquid mass ratio (GLR); the
injection pressure in the range of 7.4-13 MPa has a minor effect. Upon variation of the GLR from 0.5 to 3,
the droplet mean diameter changes from about 8.0 to 2.0 μm; very narrow droplet size distributions are also
produced. From the point of view of the atomization mechanism, the mean droplet diameter is mainly influenced
by the sudden release of the gas dissolved in the liquid. The overall analysis of the experimental data confirms
that dissolved-gas atomization allows for the formation of micrometric droplets that can produce precipitates
with controlled sizes and distributions that are useful in several fine-particles production processes
Supercritical assisted atomization under reduced pressure: formation of PEG microspheres loaded with lipophilic vitamins
Production of microspheres of Bovine Serum Albumin by supercritical assisted atomization at reduced pressure
Liposomes: From Bangham to Supercritical Fluids
Liposomes are spherical vesicles made up of an aqueous core surrounded by phospholipids. These delivery systems (DS) are largely employed as drug carriers in several industrial fields, such as pharmaceutical and nutraceutical fields. The aim of this short review is to provide a fast overview on the main fundamentals of liposomes, thought as a compact guide for researchers and students that want to approach this topic for the first time. The mini-review will focus on the definitions, production methods and characterization protocols of the liposomes produced, making a critical comparison of the main conventional and supercritical based manufacturing methods available. The literature was analyzed deeply from the first works by Dr. Bangham in 1965 to the most recent supercritical fluid applications. The advantages and disadvantages of conventional and high-pressure processes will be described in terms of solvent elimination, production at the nanometric (50–300 nm) and micrometric level (1–100 μm) and encapsulation efficiency (20–90%). The first proposed methods were characterized by a low encapsulation efficiency (20–40%), resulting in drug loss, a high solvent residue and high operating cost. The repeatability of conventional processes was also low, due to the prevalent batch mode. Supercritical-assisted methods were developed in semi-continuous layouts, resulting in an easy process scale-up, better control of liposome dimensions (polydispersity index, PDI) and also higher encapsulation efficiencies (up to 90%)
Supercritical Assisted Atomization:a Performance Comparison between Laboratory and Pilot Scale
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