Effect of RESS dynamics on polymer morphology

Lele, Ashish; Shine, Annette D.

doi:10.1021/ie00030a007

Cited by 81 publications

(70 citation statements)

References 28 publications

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“…The expansion from the supercritical state to atmospheric pressure reduces the solvent density (or strength) and initiates intense nucleation. [12][13][14][15][16][17][18][19][20][21][22] The particle formation steps include nucleation, condensation of solute molecules about the nucleii, and coagulation of particles in the free jet expansion. Recent work by Charoenchaitrakool et al has produced 2.5-µm particles by RESS with enhanced dissolution rates for the poorly water-soluble compound ibuprofen, likely due to the reduction in both particle size and crystallinity.…”

Section: Abstract: Supercritical Fluid Carbon Dioxide Rapid Expansimentioning

confidence: 99%

Phospholipid-stabilized nanoparticles of cyclosporine a by rapid expansion from supercritical to aqueous solution

et al. 2004

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INTRODUCTIONThe purpose of this research was to form stable suspensions of submicron particles of cyclosporine A, a water-insoluble drug, by rapid expansion from supercritical to aqueous solution (RESAS). A solution of cyclosporine A in CO 2 was expanded into an aqueous solution containing phospholipid vesicles mixed with nonionic surfactants to provide stabilization against particle growth resulting from collisions in the expanding jet. The products were evaluated by measuring drug loading with high performance liquid chromatography (HPLC), particle sizing by dynamic light scattering (DLS), and particle morphology by transmission electron microscopy (TEM) and x-ray diffraction. The ability of the surfactant molecules to orient at the surface of the particles and provide steric stabilization could be manipulated by changing process variables including temperature and suspension concentration. Suspensions with high payloads (up to 54 mg/mL) could be achieved with a mean diameter of 500 nm and particle size distribution ranging from 40 to 920 nm. This size range is several hundred nanometers smaller than that produced by RESAS for particles stabilized by Tween 80 alone. The high drug payloads (~10 times greater than the equilibrium solubility), the small particle sizes, and the long-term stability make this process attractive for development.The often low bioavailability of water-insoluble drugs leads to poor pharmacokinetic performance in the body. Techniques to improve bioavailability in oral or parenteral applications of water-insoluble drugs include powder micronization, the formation of micron-and submicron-size dispersions, solubility enhancement in aqueous solution by addition of appropriate surfactants, organic solvents or buffers, or drug-carrier systems such as liposomes. The payloads for drugs in liposomes are often limited because of the low volume fraction of hydrophobic regions. 1 The use of surfactants or organic solvents in parenteral administration can lead to phlebitis, anaphylaxis, hypotension, or even vasodilation.

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Section: Abstract: Supercritical Fluid Carbon Dioxide Rapid Expansimentioning

confidence: 99%

Phospholipid-stabilized nanoparticles of cyclosporine a by rapid expansion from supercritical to aqueous solution

et al. 2004

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“…Five different supercritical pre-expansion pressures (8,9,10,11 & 12 MPa) and in each pressure, five different nozzle temperatures (80, 85, 90, 95 & 100 o C) were set as experimental variables. With the exception of the above-mentioned variables, all other parameters were kept constant during all runs.…”

Section: Resultsmentioning

confidence: 99%

“…Rapid expansion of supercritical solution (RESS) which can lead to solvent-free, ultrafine and chemically pure powders is a promising process for generation of small and uniform particles. This process offers the advantage of low operational temperature, significant for processing thermally sensitive biological molecules such as many pharmaceuticals [7][8][9][10][11]. In RESS solid processing, the substance of interest is dissolved in a supercritical fluid in the vicinity of the solvent's critical temperature and pressure, where the resulting dilute solution exhibits high compressibility.…”

Section: Introductionmentioning

confidence: 99%

“…We endeavor to create a mathematical equation based on experimental results which can predict the general trends of particle size. In our previous study, the mean particle size of the RESS processed Ibuprofen powder dependence on pre-expansion pressure (8)(9)(10)(11)(12) and nozzle temperature (80-100 o C) was evaluated experimentally [30].…”

Section: Introductionmentioning

confidence: 99%

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A novel mathematical method for prediction of rapid expansion of supercritical solution (RESS) processed ibuprofen powder size distribution

Zabihi¹,

Vaziri²,

Akbarnejad³

et al. 2010

Korean J. Chem. Eng.

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A fundamental understanding of the interplay among the variables involved in a rapid expansion of supercritical solution (RESS) process is necessary in order to achieve control of product within the desired specifications. A model is proposed where the experimental data are fitted to a 2-D Sp-line equation that results in a mathematical pattern matching function that can easily be processed analytically to yield a continuous motion estimate. This model presents a novel promising method to interpolate between any two experimental results. Comparison of the mean particles size values which are calculated as a function of nozzle temperature (T N ) and pre-expansion pressure (P pre-expansion ) with the experimental data, results in a ±8% accuracy. The optimum operational point that leads to the minimum mean particles diameter (40 nm) is determined through mathematical optimization of this equation and confirmed experimentally. Furthermore, 600 more values of mean particle size are predicted by varying the nozzle temperature and dissolution pressure and the results are presented in the form of a 3-dimesional curve.

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“…[2] Different products, particles, or fibers, could be produced by controlling the RESS processing conditions, such as nozzle geometry and preexpansion temperature and pressure. [10] The formation of particles was favored from unsaturated solutions, and fibers were formed from saturated, two-phase solutions. Recently, RESS was performed on solutions of CO 2 and CO 2 -soluble fluoropolymers.…”

Section: Introductionmentioning

confidence: 99%

Novel Semiconducting Polymer Particles by Supercritical Fluid Process

Lim

Subban

Hwang

et al. 2005

Macromol. Rapid Commun.

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Summary: A simple method to prepare surfactant‐free and solvent‐free semiconducting polymer particles by using an environmentally benign supercritical carbon dioxide (scCO2) process is reported. The process of the rapid expansion of supercritical solutions (RESS) is used to produce spherical particles of poly[2‐(3‐thienyl)acetyl 3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctanoate] (PSFTE), 50–500 nm in size, from 0.1–0.5 wt.‐% PSFTE solutions in CO2 at pre‐expansion temperatures of 40 °C and pre‐expansion pressures of 276 bar.An FESEM image of PSFTE particles produced by the RESS process with CO2.magnified imageAn FESEM image of PSFTE particles produced by the RESS process with CO2.

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Effect of RESS dynamics on polymer morphology

Cited by 81 publications

References 28 publications

Phospholipid-stabilized nanoparticles of cyclosporine a by rapid expansion from supercritical to aqueous solution

Phospholipid-stabilized nanoparticles of cyclosporine a by rapid expansion from supercritical to aqueous solution

A novel mathematical method for prediction of rapid expansion of supercritical solution (RESS) processed ibuprofen powder size distribution

Novel Semiconducting Polymer Particles by Supercritical Fluid Process

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