Analysis of dissolved - gas atomization / Giuseppe Caputo in Industrial & engineering chemistry research, Vol. 49 N° 19 (Octobre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9454–9461 Titre : Analysis of dissolved - gas atomization : Supercritical CO2 dissolved in water Type de document : texte imprimé Auteurs : Giuseppe Caputo, Auteur ; Renata Adami, Auteur ; Ernesto Reverchon, Auteur Année de publication : 2010 Article en page(s) : pp. 9454–9461 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Atomization Dissolved Résumé : Supercritical dissolved-gas atomization is an atomization process in which carbon dioxide at temperature and pressure above its critical point is used as the atomizing gas. The spray characteristics in terms of droplets size and distribution have been experimentally studied using a laser diffraction method based on a Malvern apparatus. The main parameter that influences the droplets size is the gas-to-liquid mass ratio (GLR); the injection pressure in the range of 7.4−13 MPa has a minor effect. Upon variation of the GLR from 0.5 to 3, the droplet mean diameter changes from about 8.0 to 2.0 μm; very narrow droplet size distributions are also produced. From the point of view of the atomization mechanism, the mean droplet diameter is mainly influenced by the sudden release of the gas dissolved in the liquid. The overall analysis of the experimental data confirms that dissolved-gas atomization allows for the formation of micrometric droplets that can produce precipitates with controlled sizes and distributions that are useful in several fine-particles production processes. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100925w [article] Analysis of dissolved - gas atomization : Supercritical CO2 dissolved in water [texte imprimé] / Giuseppe Caputo, Auteur ; Renata Adami, Auteur ; Ernesto Reverchon, Auteur . - 2010 . - pp. 9454–9461. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 19 (Octobre 2010) . - pp. 9454–9461 Mots-clés : Gas Atomization Dissolved Résumé : Supercritical dissolved-gas atomization is an atomization process in which carbon dioxide at temperature and pressure above its critical point is used as the atomizing gas. The spray characteristics in terms of droplets size and distribution have been experimentally studied using a laser diffraction method based on a Malvern apparatus. The main parameter that influences the droplets size is the gas-to-liquid mass ratio (GLR); the injection pressure in the range of 7.4−13 MPa has a minor effect. Upon variation of the GLR from 0.5 to 3, the droplet mean diameter changes from about 8.0 to 2.0 μm; very narrow droplet size distributions are also produced. From the point of view of the atomization mechanism, the mean droplet diameter is mainly influenced by the sudden release of the gas dissolved in the liquid. The overall analysis of the experimental data confirms that dissolved-gas atomization allows for the formation of micrometric droplets that can produce precipitates with controlled sizes and distributions that are useful in several fine-particles production processes. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100925w

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Beclomethasone microparticles for wet inhalation, produced by supercritical assisted atomization / Ernesto Reverchon in Industrial & engineering chemistry research, Vol. 49 N° 24 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12747-12755 Titre : Beclomethasone microparticles for wet inhalation, produced by supercritical assisted atomization Type de document : texte imprimé Auteurs : Ernesto Reverchon, Auteur ; Renata Adami, Auteur ; Mariarosa Scognamiglio, Auteur Année de publication : 2011 Article en page(s) : pp. 12747-12755 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Supercritical state Microparticle Résumé : Supercritical assisted atomization (SAA) was used to produce micronized particles of beclomethasone dipropionate (BDP) to be used for inhalation therapy. Methanol, acetone, acetone + water 9% v/v, and methanol + water 4% v/v were tested as liquid solvents to explore their influence on particle size and crystalline structure of the precipitated powder. Particles with narrow size distributions (PSD) were obtained by changing the SAA process operating conditions. In particular, using acetone + water 9% v/v with a BDP concentration of 90 mg/mL, crystalline particles ranging between 0.2 and 4.7 μm were produced and 70% by volume of these particles ranged between 1 and 3 μm. PSD stability analysis in a wet formulation showed that BDP powder obtained by SAA does not modify over a long period of time. The results obtained on the laboratory scale plant were successfully reproduced on a pilot plant and a further refinement of the operating conditions was performed. About 30 g of BDP microparticles were produced per batch and a recovery of about 93 wt % of the micronized powder with respect to the injected quantity was obtained. The largest volumetric fraction of BDP particles falling in the range 1-3 μm was 83% on the pilot scale. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692032 [article] Beclomethasone microparticles for wet inhalation, produced by supercritical assisted atomization [texte imprimé] / Ernesto Reverchon, Auteur ; Renata Adami, Auteur ; Mariarosa Scognamiglio, Auteur . - 2011 . - pp. 12747-12755. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp. 12747-12755 Mots-clés : Supercritical state Microparticle Résumé : Supercritical assisted atomization (SAA) was used to produce micronized particles of beclomethasone dipropionate (BDP) to be used for inhalation therapy. Methanol, acetone, acetone + water 9% v/v, and methanol + water 4% v/v were tested as liquid solvents to explore their influence on particle size and crystalline structure of the precipitated powder. Particles with narrow size distributions (PSD) were obtained by changing the SAA process operating conditions. In particular, using acetone + water 9% v/v with a BDP concentration of 90 mg/mL, crystalline particles ranging between 0.2 and 4.7 μm were produced and 70% by volume of these particles ranged between 1 and 3 μm. PSD stability analysis in a wet formulation showed that BDP powder obtained by SAA does not modify over a long period of time. The results obtained on the laboratory scale plant were successfully reproduced on a pilot plant and a further refinement of the operating conditions was performed. About 30 g of BDP microparticles were produced per batch and a recovery of about 93 wt % of the micronized powder with respect to the injected quantity was obtained. The largest volumetric fraction of BDP particles falling in the range 1-3 μm was 83% on the pilot scale. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23692032

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Continuous supercritical emulsions extraction / Nunzia Falco in Industrial & engineering chemistry research, Vol. 51 N° 25 (Juin 2012)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 51 N° 25 (Juin 2012) . - pp. 8616-8623 Titre : Continuous supercritical emulsions extraction : Packed tower characterization and application to poly (lactic-co-glycolic Acid) + insulin microspheres production Type de document : texte imprimé Auteurs : Nunzia Falco, Auteur ; Ernesto Reverchon, Auteur ; Giovanna Della Porta, Auteur Année de publication : 2012 Article en page(s) : pp. 8616-8623 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Production Microsphere Packed column Emulsion Supercritical state Résumé : The continuous supercritical emulsions extraction (SEE-C) process uses a countercurrent packed tower for the continuous extraction of the organic solvents from emulsions. The continuous operation allows the formation of microspheres that are recovered at the bottom of the tower in the form of a water suspension, avoiding coalescence problems and batch-to-batch repeatability, typical of traditional processes. In this work, the packed tower used for SEE-C was characterized from a fluidodynamic point of view: flooding conditions and the allowable density difference were calculated from the experimental data. Then, an active principle (insulin) was tested for its encapsulation in poly(lactic-co-glycolic acid) (PLGA) microspheres, starting from a double emulsion: particle size, morphology, and encapsulation efficiency of the produced microdevices were evaluated. Spherical, not collapsed microspheres with a mean diameter between 1.8 μm (SD ± 0.9) and 4.8 μm (SD ± 2.8) and encapsulation efficiencies up to 70% were obtained. The very fast solvent extraction rate did not influence the particle morphology but had a significant effect on the size distribution of the precipitates which were always smaller than the starting droplets. A solvent residue (ethyl acetate) lower than about 600 ppm was obtained in all the experiments performed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26066788 [article] Continuous supercritical emulsions extraction : Packed tower characterization and application to poly (lactic-co-glycolic Acid) + insulin microspheres production [texte imprimé] / Nunzia Falco, Auteur ; Ernesto Reverchon, Auteur ; Giovanna Della Porta, Auteur . - 2012 . - pp. 8616-8623. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 25 (Juin 2012) . - pp. 8616-8623 Mots-clés : Production Microsphere Packed column Emulsion Supercritical state Résumé : The continuous supercritical emulsions extraction (SEE-C) process uses a countercurrent packed tower for the continuous extraction of the organic solvents from emulsions. The continuous operation allows the formation of microspheres that are recovered at the bottom of the tower in the form of a water suspension, avoiding coalescence problems and batch-to-batch repeatability, typical of traditional processes. In this work, the packed tower used for SEE-C was characterized from a fluidodynamic point of view: flooding conditions and the allowable density difference were calculated from the experimental data. Then, an active principle (insulin) was tested for its encapsulation in poly(lactic-co-glycolic acid) (PLGA) microspheres, starting from a double emulsion: particle size, morphology, and encapsulation efficiency of the produced microdevices were evaluated. Spherical, not collapsed microspheres with a mean diameter between 1.8 μm (SD ± 0.9) and 4.8 μm (SD ± 2.8) and encapsulation efficiencies up to 70% were obtained. The very fast solvent extraction rate did not influence the particle morphology but had a significant effect on the size distribution of the precipitates which were always smaller than the starting droplets. A solvent residue (ethyl acetate) lower than about 600 ppm was obtained in all the experiments performed. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26066788

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Nanostructured PLLA-hydroxyapatite scaffolds produced by a supercritical assisted technique / Ernesto Reverchon in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5310–5316 Titre : Nanostructured PLLA-hydroxyapatite scaffolds produced by a supercritical assisted technique Type de document : texte imprimé Auteurs : Ernesto Reverchon, Auteur ; Paola Pisanti, Auteur ; Stefano Cardea, Auteur Année de publication : 2009 Article en page(s) : pp. 5310–5316 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Bone scaffolds Nanostructural properties Supercritical fluid assisted technique Hydroxyapatite nanoparticles Résumé : Temporary bone scaffolds can surrogate the extracellular matrix to favor the regeneration of tissues and organs. It is very difficult to obtain the coexistence of the macro-, micro-, and nanostructural properties necessary to mimic the organization of the human bone. To obtain all of these characteristics, we tested a supercritical fluid assisted technique for the formation of PLLA/ceramic scaffolds using hydroxyapatite (HA) nanoparticles loaded at up to 50% by weight of the polymer to improve the biomimethism and the mechanical properties of the scaffolds. We produced poly(l-lactic acid) scaffolds in relatively short time ( En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018752 [article] Nanostructured PLLA-hydroxyapatite scaffolds produced by a supercritical assisted technique [texte imprimé] / Ernesto Reverchon, Auteur ; Paola Pisanti, Auteur ; Stefano Cardea, Auteur . - 2009 . - pp. 5310–5316. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5310–5316 Mots-clés : Bone scaffolds Nanostructural properties Supercritical fluid assisted technique Hydroxyapatite nanoparticles Résumé : Temporary bone scaffolds can surrogate the extracellular matrix to favor the regeneration of tissues and organs. It is very difficult to obtain the coexistence of the macro-, micro-, and nanostructural properties necessary to mimic the organization of the human bone. To obtain all of these characteristics, we tested a supercritical fluid assisted technique for the formation of PLLA/ceramic scaffolds using hydroxyapatite (HA) nanoparticles loaded at up to 50% by weight of the polymer to improve the biomimethism and the mechanical properties of the scaffolds. We produced poly(l-lactic acid) scaffolds in relatively short time ( En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018752

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Supercritical phase Inversion to form drug-loaded poly(vinylidene fluoride-co-hexafluoropropylene) membranes / Stefano Cardea in Industrial & engineering chemistry research, Vol. 49 N° 6 (Mars 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2783–2789 Titre : Supercritical phase Inversion to form drug-loaded poly(vinylidene fluoride-co-hexafluoropropylene) membranes Type de document : texte imprimé Auteurs : Stefano Cardea, Auteur ; Margherita Sessa, Auteur ; Ernesto Reverchon, Auteur Année de publication : 2010 Article en page(s) : pp. 2783–2789 Note générale : Inustrial Chemistry Langues : Anglais (eng) Mots-clés : Drug  Poly  vinylidene  fluoride  co-hexafluoropropylene  Membranes Résumé : Membranes loaded with an active principle are one of the alternatives proposed to obtain controlled release pharmaceutical formulations. Until now, several methods have been proposed for the fabrication of membranes as drug delivery devices, such as phase inversion, gas foaming/particulate leaching, and solvent evaporation. Supercritical CO2 (SC-CO2) phase inversion offers an alternative process to obtain solvent-free membranes with short processing times, avoiding the collapse of the structure. We prepared poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF−HFP) loaded membranes by SC-CO2 phase inversion, performing experiments at pressures ranging between 150 and 250 bar and at temperatures ranging between 35 and 55 °C. We selected as the base case the PVDF−HFP−acetone solution at 15% w/w polymer and modified the drug (amoxicillin) concentration from 20 to 50% w/w with respect to PVDF−HFP. Different membranes morphologies, ranging from nanometric gel-like networks (mean pores diameter of about 150 nm) to micrometric cellular structures (mean cells diameter ranging between 5 and 12 μm), and different drug distributions were obtained, depending on the process conditions. Drug-controlled release experiments were also performed to study the kinetics and duration of the release process. Note de contenu : Bibiogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901616n [article] Supercritical phase Inversion to form drug-loaded poly(vinylidene fluoride-co-hexafluoropropylene) membranes [texte imprimé] / Stefano Cardea, Auteur ; Margherita Sessa, Auteur ; Ernesto Reverchon, Auteur . - 2010 . - pp. 2783–2789. Inustrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 6 (Mars 2010) . - pp. 2783–2789 Mots-clés : Drug  Poly  vinylidene  fluoride  co-hexafluoropropylene  Membranes Résumé : Membranes loaded with an active principle are one of the alternatives proposed to obtain controlled release pharmaceutical formulations. Until now, several methods have been proposed for the fabrication of membranes as drug delivery devices, such as phase inversion, gas foaming/particulate leaching, and solvent evaporation. Supercritical CO2 (SC-CO2) phase inversion offers an alternative process to obtain solvent-free membranes with short processing times, avoiding the collapse of the structure. We prepared poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF−HFP) loaded membranes by SC-CO2 phase inversion, performing experiments at pressures ranging between 150 and 250 bar and at temperatures ranging between 35 and 55 °C. We selected as the base case the PVDF−HFP−acetone solution at 15% w/w polymer and modified the drug (amoxicillin) concentration from 20 to 50% w/w with respect to PVDF−HFP. Different membranes morphologies, ranging from nanometric gel-like networks (mean pores diameter of about 150 nm) to micrometric cellular structures (mean cells diameter ranging between 5 and 12 μm), and different drug distributions were obtained, depending on the process conditions. Drug-controlled release experiments were also performed to study the kinetics and duration of the release process. Note de contenu : Bibiogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901616n

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