A brief review of the supercritical antisolvent (SAS) technique for the preparation of nanocatalysts to be used in biodiesel production

In an era where sustainability is becoming the main driving force for research and development, supercritical fluids-based techniques are presented as a very efficient alternative technology to conventional extraction, purification, and recrystallization processes. Supercritical antisolvent (SAS) precipitation is a novel technique that can replace liquid antisolvent precipitation techniques. Additionally, through the optimization of precipitation operating conditions, morphology, particle size, and particle size distribution of nanoparticles can be controlled. As an antisolvent, supercritical carbon dioxide (scCO2) is far more sustainable than its conventional liquid counterparts; not only does it have a critical point (304 K and 73.8 bar) on its phase diagram that allows for the precipitation processes to be developed so close to room temperature, but also its recovery and, consequently, the precipitated solute purification stage is considerably simpler. This technique can be used efficiently for preparing nanocatalysts to be used in biodiesel production processes.info:eu-repo/semantics/publishedVersio

Application of supercritical antisolvent method in drug encapsulation: a review

The review focuses on the application of supercritical fluids as antisolvents in the pharmaceutical field and demonstrates the supercritical antisolvent method in the use of drug encapsulation. The main factors for choosing the solvent and biodegradable polymer to produce fine particles to ensure effective drug delivery are emphasized and the effect of polymer structure on drug encapsulation is illustrated. The review also demonstrates the drug release mechanism and polymeric controlled release system, and discusses the effects of the various conditions in the process, such as pressure, temperature, concentration, chemical compositions (organic solvents, drug, and biodegradable polymer), nozzle geometry, CO2 flow rate, and the liquid phase flow rate on particle size and its distribution

Supercritical Antisolvent Precipitation of Quercetin Systems: Preliminary Experiments

Flavonoids have attracted a lot of attention due to their antioxidant, antitumor and antibacterial activities. Quercetin (3,5,7,3,4-pentahydroxyflavone) is a polyphenolic flavonoid that shows several biological effects including a strong inhibitory effect on the growth of several human and animal cancer cell lines and enhances the antiproliferative effect of cisplatin both in-vitro and in-vivo. In spite of a variety of its biological effects. Quercetin is very poorly soluble in water, which has limited its absorption upon oral administration. As known, the solubility of drug is often due to the increase of the surface/volume ratio which implies the increase of the number of surface atoms (or molecules) with respect to the number of bulk atoms (or molecules). With this aim, we investigated the use of supercritical antisolvent (SAS) technique for Quercetin microparticles generation finding the best operative conditions through the Peng Robinson’s Equation of State. The obtained simulation behaviors were confirmed by experimental precipitation: the physicochemical characterizations of the samples were also performe

Precipitation of submicron particles of rutin using supercritical antisolvent process.

Las partículas submicrónicas de rutina se prepararon mediante un proceso supercrítico antisolvente (SAS). La selección del disolvente adecuado determinó el éxito del proceso de precipitación. Se seleccionó una mezcla de acetona y DMSO en una proporción 9:1 para estudiar los principales parámetros que influyen en el proceso SAS en términos de tamaño de partícula, distribución de tamaño y morfología de partícula. Se produjeron partículas más pequeñas a mayor temperatura y presión, y con una menor concentración inicial de la solución. Se recomienda un caudal de solución líquida más bajo para obtener partículas submicrónicas, pero el caudal de CO2y el diámetro de la boquilla tuvieron un efecto insignificante en el tamaño de las partículas, al menos en los niveles evaluados. Los polvos precipitados fueron analizados por microscopia electrónica de barrido (SEM), transformada infrarroja de Fourier (FTIR), Difracción de rayos X (XRD) y calorimetría de barrido diferencial (DSC). El proceso SAS contribuyó a la deshidratación de la rutina, confiriendo así un mayor valor añadido. Además, durante el proceso se produjo una amorfina de las muestras procesadas. Las partículas de rutina procesadas se disolvieron más rápidamente que los fluidos simulados de rutina comercial y esto está relacionado con la reducción del tamaño de partícula y la pérdida de cristalinidad debido a la amorfización. Este efecto fue más pronunciado en fluidos intestinales simulados que en líquidos gástricos.tSpherical submicron particles of rutin were prepared by a supercritical antisolvent process (SAS). Selec-tion of the appropriate solvent determined the success of the precipitation process. A mixture of acetoneand DMSO in a 9:1 ratio was selected in order to study the main parameters that influence the SAS processin terms of particle size, size distribution and particle morphology. Smaller particles were produced athigher temperature and pressure, and with a lower initial concentration of the solution. A lower liquidsolution flow rate is recommended to obtain submicron particles but the CO2flow rate and nozzle diam-eter had a negligible effect on particle size, at least at the levels evaluated. The precipitated powders wereanalysed by Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-RayDiffraction (XRD) and Differential Scanning Calorimetry (DSC). The SAS process contributed to the dehy-dration of rutin, thus conferring higher added value. Moreover, amorphization of the processed sampleswas produced during the process. Processed rutin particles dissolved more rapidly than commercial rutinin simulated fluids and this is related to the particle size reduction and the loss of crystallinity due toamorphization. This effect was more pronounced in simulated intestinal fluids than in gastric fluids

Co-precipitation of amoxicillin and ethylcellulose microparticles by supercritical antisolvent process

Las micropartículas de etilcelulosa (CE) y amoxicilina (AMC) han sido precipitadas por un proceso supercrítico antisolvente (SAS) que utiliza CO2 como antisolvente y una mezcla de diclorometano (DCM) y dimetilsulfóxido (DMSO) como disolventes. Se evaluaron combinaciones de tres temperaturas (308, 323 y 333 K) y cuatro presiones (100, 150, 200 y 250 bar) en el vaso y el resto de las variables se mantuvieron constantes (p.e. caudal de CO2, caudal de muestreo, tiempo de lavado, diámetro de la boquilla y relación amoxicilina:celulosa de etilo). Se utilizó microscopia electrónica de barrido (SEM), espectroscopia fotoelectrónica de rayos X (XPS) y análisis elemental (EA) para determinar el tamaño y la forma de las partículas y confirmar la presencia de ambos compuestos en los precipitados resultantes. En la mayoría de los casos, amoxicilina mixta y partículas de celulosa de etilo se produjeron con tamaños en el rango de micrómetros. Se investigaron los efectos de presión y temperatura sobre la co-precisión. El comportamiento de liberación de las micropartículas precipitadas por el proceso SAS se evaluó en dos fluidos biológicos - fluidos gástricos simulados y fluidos intestinales simulados. Los materiales co-precipitados permitieron una tasa de liberación de fármaco más lenta que el fármaco puroMicroparticles of ethyl cellulose (EC) and amoxicillin (AMC) have been precipitated by a supercritical antisolvent process (SAS) using CO2 as the antisolvent and a mixture of dichloromethane (DCM) and dimethyl sulfoxide (DMSO) as solvents. Combinations of three temperatures (308, 323 and 333 K) and four pressures (100, 150, 200 and 250 bar) were assessed in the vessel and the rest of the variables were held constant (i.e. CO2 flow rate, sample flow rate, washing time, nozzle diameter and the amoxicillin:ethyl cellulose ratio). Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and elemental analysis (EA) were used to determine the particle size and shape and to confirm the presence of both compounds in the resulting precipitates. In most cases, mixed amoxicillin and ethyl cellulose particles were produced with sizes in the micrometer range. Pressure and temperature effects on the co-precipitation were investigated. The release behaviour of the microparticles precipitated by the SAS process was evaluated in two biological fluids – simulated gastric and simulated intestinal fluids. Co-precipitated materials allowed a slower drug release rate than pure dru

Supercritical antisolvent precipitation of PHBV microparticles

The micronization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from organic solutions using supercritical antisolvent (SAS) technique has been successfully achieved. SASexperiments were carried out at different operational conditions and microspheres with mean diameters ranging from 3 to 9 mwere obtained. The effect of CO2 and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a dichloromethane (DCM) solution. The best process conditions for this mixture were, according to our study, 40 ◦C, 100 bar, 1mLmin−1 liquid flow and 10 L min−1 carbon dioxide flow. Experiments with polymers containing different HV percentages were carried out. The powders obtained became more spherical as the HV content decreased