Procédé supercritique continu de fractionnement de microalgues (2017-2018)
Publications scientifiques au M2P2
Rania Djerafi, Andri Swanepoel, Christelle Crampon, Lonji Kalombo, Philip Labuschagne, et al.. Supercritical antisolvent co-precipitation of rifampicin and ethyl cellulose. European Journal of Pharmaceutical Sciences, Elsevier, 2017, 102, pp.161 - 171. ⟨10.1016/j.ejps.2017.03.016⟩. ⟨hal-01524709⟩ Plus de détails...
L.M. Santiago, Y. Masmoudi, A. Tarancón, R. Djerafi, H. Bagán, et al.. Polystyrene based sub-micron scintillating particles produced by supercritical anti-solvent precipitation. Journal of Supercritical Fluids, Elsevier, 2015, 103, pp.18-27. ⟨10.1016/j.supflu.2015.04.015⟩. ⟨hal-01297575⟩ Plus de détails...
scintillation microspheres (PSm) are a novel material employed in the measurement of radioactivity (α and β emitters). This work is focused on the formation of plastic scintillation particles through the precipitation and encapsulation of two fluorescent solutes (2,5-diphenyloxazol (PPO) and 1,4-Bis(5-phenyloxazol-2-yl) benzene (POPOP)) and an aromatic solvent 2,6-diisopropyl-naphthalene (DIN), which acts as an enhancer for α and β emitters discrimination, into a polymeric matrix of Polystyrene (PS) by Supercritical Anti-Solvent process (SAS) using ethyl acetate (EtAc) for dissolving the PS and supercritical CO2 as antisolvent. Different process parameters were varied; solute concentration in the organic solution (W, wt%), injection velocity of the organic solution (u, ms−1), molar ratio of the organic solvent regarding to CO2 (XEA) and injection capillary tube diameter (μm). In the different experimental conditions tested, SAS coprecipitation was successfully achieved resulting in yields higher than 90% and very low quantities of residual solvent (600–1200 ppm). The different Polystyrene based particles obtained were nearly spherical sub-micron particles (ranged between 150 and 400 nm) and also agglomerates of a few micrometers were observed in most of the studied conditions. Radiometric capacities of particles were evaluated through measuring different beta and alpha emitting radionuclide. The coprecipitates showed scintillation behavior when fluorescent solutes were added, therefore confirming their encapsulation.
L.M. Santiago, Y. Masmoudi, A. Tarancón, R. Djerafi, H. Bagán, et al.. Polystyrene based sub-micron scintillating particles produced by supercritical anti-solvent precipitation. Journal of Supercritical Fluids, Elsevier, 2015, 103, pp.18-27. ⟨10.1016/j.supflu.2015.04.015⟩. ⟨hal-01297575⟩
Quercetin is a strong naturally occurring antioxidant that is exploited in pharmaceutical and cosmeticsapplications. Unfortunately, quercetin is highly susceptible to oxidation. Besides, its poor solubility inwater and low bioavailability upon oral administration limit the use in drug formulations for the treat-ment of human diseases. In an effort to overcome these drawbacks, the micronization and coprecipitationof quercetin particles with a low-cost biocompatible polymer (ethyl cellulose, EC) was studied by usingsupercritical anti-solvent process (SAS) with a non-toxic solvent ethyl acetate. The results showed thatSAS micronization of quercetin led to a reduction in the quercetin particle size and crystallinity withouta change in the needle-like habit. SAS coprecipitation of quercetin with EC at moderate pressure andtemperature (10 MPa and 35◦C) led to obtaining quasi-spherical particles. The coated polymer avoidthe growth of quercetin crystals, thus amorphous particles in the submicron range (mean size rangingbetween 150 and 350 nm) were formed. Promising coprecipitation results were reached with quite highprocess yields (above 85%) and encapsulation efficiencies up to 99% that provided a high stability to thecoated quercetin with EC against oxidation.
Maria Teresa Fernández-Ponce, Yasmine Masmoudi, Rania Djerafi, Lourdes Casas, Casimiro Mantell, et al.. Particle design applied to quercetin using supercritical anti-solvent techniques. Journal of Supercritical Fluids, Elsevier, 2015, 105, pp.119 - 127. ⟨hal-01266553⟩
Supercritical anti-solvent (SAS) process is considered to be a clean technology suitable for particle design. It is generally used in order to micronize compounds of interest under mild operating conditions of temperature and with very low residual solvent traces in the end-product. By varying the process parameters, the properties of the produced powders can be adjusted with defined size (generally micron or nanometer sized particles), morphology and a narrow particle size distribution. There is currently a growing interest for the elaboration of controlled delivery systems. For this purpose, the SAS process can also be applied in order to co-precipitate molecules of interest with biocompatible and/or biodegradable polymers. An experimental study dealing with supercritical anti-solvent (SAS) precipitation has been carried out in order to micronize a biocompatible polymer, ethyl cellulose, widely used as a drug carrier in controlled delivery systems for oral administration. Supercritical carbon dioxide was used as anti-solvent for the polymer and ethyl acetate (EtAc), generally recognized as safe (GRAS) by the FDA (Food and Drug Administration) as solvent. The influence of the variation of the main operating parameters upon the characteristics of the micronized polymer was evaluated. In particular, the temperature (308, 318 and 333 K), the polymer concentration (1, 3 and 4 wt%), the EtAc/CO2 molar ratio (5 and 8 mol%) and the capillary tube diameter (127 and 254 μm) while pressure was kept constant and equal to 10 MPa. Using a low organic solution concentration of 1 wt% and at a temperature of 308 K, ethyl cellulose was successfully micronized in submicron particles with a mean size of 300 nm. However, increasing the temperature or the polymer concentration in the organic solution favored the particle coalescence and even led to fiber formation.
Rania Djerafi, Yasmine Masmoudi, Christelle Crampon, Abdeslam-Hassen Meniai, Elisabeth Badens. Supercritical anti-solvent precipitation of ethyl cellulose. Journal of Supercritical Fluids, Elsevier, 2015, 105, pp.92-98. ⟨hal-01266175⟩