scholarly journals Drug Delivery Properties of Macroporous Polystyrene Solid Foams

2012 ◽  
Vol 15 (1) ◽  
pp. 197 ◽  
Author(s):  
Cristina Canal ◽  
Rosa Maria Aparicio ◽  
Alejandro Vilchez ◽  
Jordi Esquena ◽  
Maria José García-Celma
Keyword(s):  
Phase Inversion ◽  
Continuous Phase ◽  
Pharmaceutical Dosage Forms ◽  
Temperature Method ◽  
Lipophilic Molecule ◽  
Solid Foams ◽  
Solid Foam ◽  
Drug Incorporation ◽  
Concentrated Emulsions ◽  
Very High

Purpose. Polymeric porous foams have been evaluated as possible new pharmaceutical dosage forms. Methods. These materials were obtained by polymerization in the continuous phase of highly concentrated emulsions prepared by the phase inversion temperature method. Their porosity, specific surface and surface topography were characterized, and the incorporation and release of active principles was studied using ketoprofen as model lipophilic molecule. Results. Solid foams with very high pore volume, mainly inside macropores, were obtained by this method. The pore morphology of the materials was characterized, and very rough topography was observed, which contributed to their nearly superhydrophobic properties. These solid foams could be used as delivery systems for active principles with pharmaceutical interest, and in the present work ketoprofen was used as a model lipophilic molecule. Conclusions. Drug incorporation and release was studied from solid foam disks, using different concentrations of the loading solutions, achieving a delayed release with short lag-time. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

Phase Inversion in Two-Phase Liquid Systems

1992 ◽  
Vol 57 (7) ◽  
pp. 1419-1423
Author(s):  
Jindřich Weiss
Keyword(s):  
Interfacial Tension ◽  
Phase Inversion ◽  
Continuous Phase ◽  
Considerable Effect ◽  
Weak Dependence ◽  
Dispersed Phase ◽  
Two Phase ◽  
Liquid Systems ◽  
Phase Liquid

New data on critical holdups of dispersed phase were measured at which the phase inversion took place. The systems studied differed in the ratio of phase viscosities and interfacial tension. A weak dependence was found of critical holdups on the impeller revolutions and on the material contactor; on the contrary, a considerable effect of viscosity was found out as far as the viscosity of continuous phase exceeded that of dispersed phase.

Effect of Shear and Water Cut on Phase Inversion and Droplet Size Distribution in Oil–Water Flow

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Mo Zhang ◽  
Ramin Dabirian ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Phase Inversion ◽  
Droplet Size Distribution ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Water Emulsion ◽  
Inversion Region ◽  
Oil Water ◽  
Water Cut

Oil–water dispersed flow occurs commonly in the petroleum industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties, and other factors. Production equipment, such as pumps and chokes, generates shear in oil–water mixture flow, which has a strong effect on phase inversion phenomena. The objective of this paper is to investigate the effects of shear intensity and water cut (WC) on the phase inversion region and also the droplet size distribution. A state-of-the-art closed-loop two phase (oil–water) flow facility including a multipass gear pump and a differential dielectric sensor (DDS) is used to identify the phase inversion region. Also, the facility utilizes an in-line droplet size analyzer (a high speed camera), to record real-time videos of oil–water emulsion to determine the droplet size distribution. The experimental data for phase inversion confirm that as shear intensity increases, the phase inversion occurs at relatively higher dispersed phase fractions. Also the data show that oil-in-water emulsion requires larger dispersed phase volumetric fraction for phase inversion as compared with that of water-in-oil emulsion under the same shear intensity conditions. Experiments for droplet size distribution confirm that larger droplets are obtained for the water continuous phase, and increasing the dispersed phase volume fraction leads to the creation of larger droplets.

Phase Behavior and Nano-emulsion Formation by the Phase Inversion Temperature Method

Langmuir ◽  
2004 ◽  
Vol 20 (16) ◽  
pp. 6594-6598 ◽  
Author(s):  
Paqui Izquierdo ◽  
Jordi Esquena ◽  
Tharward F. Tadros ◽  
Joseph C. Dederen ◽  
Jin Feng ◽  
...  
Keyword(s):  
Phase Behavior ◽  
Phase Inversion ◽  
Inversion Temperature ◽  
Temperature Method ◽  
Nano Emulsion ◽  
Phase Inversion Temperature

Formation of Carbon Dioxide in Water Miniemulsions Using the Phase Inversion Temperature Method

Langmuir ◽  
2002 ◽  
Vol 18 (8) ◽  
pp. 3039-3046 ◽  
Author(s):  
Petros A. Psathas ◽  
Michelle L. Janowiak ◽  
Luis H. Garcia-Rubio ◽  
Keith P. Johnston
Keyword(s):  
Carbon Dioxide ◽  
Phase Inversion ◽  
Inversion Temperature ◽  
Temperature Method ◽  
Phase Inversion Temperature

scholarly journals Wetting Fraction in a Tubular Reactor with Solid Foam Packing and Gas/Liquid Co-Current Downflow

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 396
Author(s):  
Iman Mohammed ◽  
Uwe Hampel
Keyword(s):  
Liquid Phase ◽  
Mass Transfer Rate ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Electrochemical Measurement ◽  
Limiting Current ◽  
Structured Catalysts ◽  
Solid Foams ◽  
Solid Foam ◽  
Wetted Area

The performance of fixed-bed reactors with structured catalysts depends heavily on the gas–liquid–solid contacting pattern. For a broad range of flow conditions, the liquid phase does not cover the solid surface of the packing homogeneously; this is known as partial wetting. The wetting fraction in solid foams was obtained using a modified electrochemical measurement method with adaption of the limiting-current technique in different pre-wetting scenarios. The external wetting fraction, which is defined as fraction of the external solid-foam area covered by the liquid phase to the total external solid-foam area, is directly linked to the overall rate of reaction through the overall liquid mass transfer rate. The wetting fraction decreased with an increase in foam density, a process which was related to decreasing the strut thickness, increasing foam surface area, and consequently, decreasing the wetted area. Additionally, the results indicate that a better distribution of liquid and an increased wetting fraction occurred when a spray nozzle distributor was applied. A new wetting correlation for solid foams is proposed to estimate the wetting fraction with consideration of foam morphology and flow regime.

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