Precipitation with antisolvent

D. J. Dixon, "Formation of Polymeric Materials by Precipitation with a Compressed Fluid Antisolvent," Ph.D. Dissertation, University of Texas at Austin, Austin, Tex., 1992. 

Precipitation inhibitors, dispersants contrasted, 3 686 Precipitation leachate procedure, synthetic, 25 868-869 Precipitation reactions, for niobium and tantalum determination, 27 142-143 Precipitation reagents, protein, 22 133 Precipitation with compressed antisolvent (PCA) process, 24 17, 18 Precipitator dust, in phosphorus manufacture, 19 12 Precipitators, electrostatic, 23 180 Precision agriculture, 23 328 26 269-270 Precision measurement techniques, noble gases in, 27 370 Precision scales, 26 245 Preconcentration, of uranium ores, 25 401 Pre-crosslinked polychloroprene grades, 19 852... 

Dixon, D. J., Johnston, K. P. and Bodmeier, R. A. AIChE Jl. 39 (1993) 127. Polymeric materials formed by precipitation with a compressed fluid antisolvent. 

Gas anti-solvent processes (GASR, gas anti-solvent recrystallization GASP, gas antisolvent precipitation SAS, supercritical anti-solvent fractionation PCA, precipitation with a compressed fluid anti-solvent SEDS, solution-enhanced dispersion of solids) differ in the way the contact between solution and anti-solvent is achieved. This may be by spraying the solution in a supercritical gas, spraying the gas into the liquid solution. 

Jarmer DJ, Lengsfeld CS, Randolph TW. 2006. Scale-up criteria for an injector with a confined mixing chamber during precipitation with a compressed fluid antisolvent. J. Supercritical Fluids 37 242-253. 

Gas [Gas antisolvent] A process for separating dissolved materials by selective precipitation with added supercritical carbon dioxide. First used for recrystallizing the explosive RDX subsequently used for recrystallizing other explosives, pharmaceuticals, fine chemicals, and food products. Another use has been for precipitating insulin particles from dimethylsulfoxide solution. 

PCA [Precipitation with a Compressed Antisolvent] A process for making a solid with unusual morphology by spraying a solution of it into a supercritical fluid. The process resembles spray drying into a supercritical fluid. Used for making microspheres, microporous fibers, and hollow... 

Supercritical drying and particle formation processes are also important areas in SCCO2 based materials chemistry. Some of the particle processing methods available, such as precipitation with compressed antisolvent (PCA), are shown schematically in Chapter 9. 

Young, T.J. Johnston, K.P. Mishima, K. Tanaka, H. Encapsulation of lysozyme in a biodegradable polymer by precipitation with a vapor-over-liquid antisolvent. J. Pharm. Sci. 1999, 88 (6), 640-650. 

Jarmer, D.J. Lengsfeld, C.S. Randolph, T.W. Manipulation of particle size distribution of poly(-lactic acid) nanoparticles with a jet-swirl nozzle during precipitation with a compressed antisolvent. J. Supercrit. Fluids 2003, 27 (3), 317-336. 

Falk, R. Randolph, T. Meyer, J. Kelly, R. Manning, M. Controlled release of ionic compounds from poly(L-lactide) microspheres produced by precipitation with compressed antisolvent. J. Control. Release 1997, 44, 77-85. 

Gas antisolvent processes can be performed in a semicontinuous mode. In this case the solution and the antisolvent are continuously introduced in the system until the desired amount of the product is formed. The introduction of the solution is then stopped and the DG flux extracts the residual solvent from the system. The system is then depressurized to enable collection of the product. The solution is generally introduced through an atomization nozzle that favors the prompt expansion of the solution and the formation of small particles. Different process configurations have been utilized, i.e., co- and countercurrent introduction of the solution and antisolvent fluxes and various nozzles have been designed. The process is referred to by different acronyms such as ASES (aerosol solvent extraction system), SAS (supercritical antisolvent), SEDS (solution enhanced dispersion by supercritical fluids), PCA (precipitation with a compressed fluid antisolvent), GASR (gas antisolvent recrystallization), GASP (gas antisolvent precipitation). 

PRECIPITATION WITH A COMPRESSED FLUID ANTISOLVENT (PCA), A SUPERCRITICAL ANTISOLVENT (SAS), AND THE AEROSOL SOLVENT EXTRACTION SYSTEM (ASES) PROCESSES... 

Dozens of drugs have been recrystallized by means of the precipitation with a compressed fluid antisolvent (PCA) and the supercritical antisolvent (SAS) and aerosol solvent extraction system (ASES) processes. 

Mawson S, Kanakia S, Johnston KP. Coaxial nozzle for control of particle morphology in precipitation with a compressed fluid antisolvent. J Appl Poly Sci 1997 64 2105-2118. 

Magnan C, Badens E, Commenges N, Charbit G. Soy lecithin micronization by precipitation with a compressed fluid antisolvent—influence of process parameters. J Supercrit Fluids 2000 19 69-77. 

The organic-C02 interface plays a central role in physical particle formation processes including rapid expansion from supercritical solution (RESS), precipitation with a compressed antisolvent (PCA, also called SAS... 

Mawson S, Johnston KP, Betts DE, McClain JB, DeSimone JM. Stabilized polymer microparticles by precipitation with a compressed fluid antisolvent. I. Poly(fluoro acrylates). Macromolecules 1997 30, 71-77. 

Mawson S, Yates MZ, O Neill ML, Johnston KP. Stabilized pol5mer microparticles by precipitation with a compressed fluid antisolvent. 2. Poly(propylene oxide) and poly(butylene oxide)-based copolymers. Langmuir 1997 13 1519-1528. 

Young TJ, Johnston KP. Encapsulation of lysoz5une by precipitation with a vapor-over-liquid antisolvent. J Pharm Sci 1999 88 640-650. 

As described in Chapter 3, several SCF techniques are available for the preparation of drug delivery systems. These include rapid expansion of supercritical solutions (RESS), gas antisolvent recrystallization (GAS), supercritical antisolvent recrystallization (SAS), supercritical antisolvent with enhanced mass transfer (SAS-EM), solution-enhanced dispersion by supercritical fluids (SEDS), supercritical fluid nucleation (SFN), precipitation with compressed antisolvent (PCA), and aerosolized supercritical extraction of solvents (ASES). While RESS and SFN involve the expansion of a supercritical fluid solution of a drug to form drug particles, GAS, SAS, SAS-EM, SEDS, PCA, and ASES use a supercritical fluid as an antisolvent to precipitate particles of a drug dissolved in an organic solvent (5). General RESS and GAS processes are further elaborated in Sections 1.1.1 and 1.1.2. 

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