Particle Generation
Particle processes using supercritical carbon dioxide (CO2)
Numerous processes with supercritical CO2 have been developed which allow the generation or modification of fine particles with defined particle size distributions in micro- and even nano-scale of certain shape and/or determined morphology. This new technology is of highest relevance to generate pharmaceutical products and substances. The dosing and release properties of active pharmaceutical ingredients (APIs) are significantly influenced by the particle properties. New drugs with exact and controlled properties will be possible in the near future by using these new processes complementing traditional granulation and spray drying processes
Schematic depiction of the GAS-Process (Gas antisolvent crystallization)
Characteristics of high pressure micronisation
Physical characteristics when applying supercritical fluids to melts/solutions:
reduction of viscosity
reduction of surface tension.
Quick super-saturation by pressure change and contact to supercritical fluid, respectively
High nucleation rate, small growth rate
Particles in micro- or nano-scale possible
Schematic depiction of the RESS-Process (Rapid Expansion of Supercritical Solutions)
Advantages of using supercritical fluids
Size: micro- to nanometer
Narrow size distribution adjustable
Control of geometry (spherical, needle, etc.)
Morphology (smooth, porous, massive) controllable
Applicable to difficult substances, for example with high melting points or high viscosity
No thermal stress due to mild temperature conditions
No oxidation due to inert atmosphere
Possibility of generation of composites
Schematic depiction of the PGSS™-Process (Particles from saturated solutions)