Hollow microspheres with binary colloidal and polymeric membrane: Effect of polymer and particle concentrations

2010 ◽  
Vol 21 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Olivier J. Cayre ◽  
Simon Biggs
Keyword(s):  
Hollow Microspheres ◽  
Polymeric Membrane ◽  
Membrane Effect

Solvothermal synthesis, characterisation and luminescent property of multilayered SnO 2 hollow microspheres

2014 ◽  
Vol 9 (2) ◽  
pp. 87-90 ◽  
Author(s):  
Zhi Yuan Wang ◽  
Feng Ping Wang ◽  
Yan Li ◽  
Ming Yan Li ◽  
Muhammad Zubair Iqbal ◽  
...  
Keyword(s):  
Luminescent Property ◽  
Solvothermal Synthesis ◽  
Hollow Microspheres

Synthesis and sensitivity of ZnO and Au-ZnO hollow microspheres

2018 ◽  
Vol 35 (3) ◽  
pp. 267
Author(s):  
Jianbo XING ◽  
Yuan CEN ◽  
Xue YIN ◽  
Yu DU ◽  
Qinhe PAN
Keyword(s):  
Hollow Microspheres

Preparation and Evaluation of a Gas Formation-based Multiple-Unit Gastro-Retentive Floating Delivery System of Dipyridamole

2012 ◽  
Vol 5 (1) ◽  
pp. 1607-1616
Author(s):  
Y. Madhusudan Rao ◽  
Katakam V V ◽  
S Reddy ◽  
J M Somagoni ◽  
P K Panakanti ◽  
...  
Keyword(s):  
Drug Release ◽  
Delivery System ◽  
Polymeric Membrane ◽  
Wet Granulation ◽  
Physical Parameters ◽  
Gastric Residence Time ◽  
Gas Formation ◽  
Multiple Unit ◽  
Model Drug

The aim of this study was to prepare mini tablets to be filled into a capsule that is designed to float on the gastric contents based on gas formation technique. The drug-containing core mini-tablets were prepared by wet granulation method followed by a coating of the core units with seal coating, an effervescent layer and a gas-entrapping polymeric membrane (Eudragit RS30D, RL30D). Dipyridamole, which is predominantly absorbed in the upper part of GI tract and unabsorbed/insoluble at the lower intestine, was used as a model drug. The effect of the preparative parameters like amount of the effervescent agent layered onto the seal coated units, type and coating level of the gas-entrapping polymeric membrane, floating ability and drug release properties of the multiple-unit FDDS were evaluated. The formulations were evaluated for pharmacopoeial quality control tests. Physical parameters were found to be within the acceptable limits. The system using Eudragit® RL30D as a gas-entrapping polymeric membrane exhibited floating properties. The time to float decreased as amount of the effervescent agent increased and coating level of gas-entrapping polymeric membrane decreased. The optimum system exhibited complete floating within 3 minutes and maintained that buoyancy over a period of 8 hours. The drug release was sustained and linear with the square root of time. Increasing the coating level of the gas-entrapping polymeric membrane decreased drug release. Both the rapid-floating and sustained-release properties were achieved in the multiple-unit floating delivery system developed in this study. The in vivo gastric residence time was examined by radiograms and it was found that the units remained in the stomach for about 6 hours. The analysis of the dissolution data after storage at 40°C and 75% RH for 6 months showed no significant change indicating good stability.

Characterization of a Polymeric Membrane for the Separation of Hydrogen in a Mixture with CO2

2016 ◽  
Vol 9 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Dionisio H. Malagón-Romero ◽  
Alexander Ladino ◽  
Nataly Ortiz ◽  
Liliana P. Green
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Production ◽  
Test Performance ◽  
Low Cost ◽  
Time Lag ◽  
Polymeric Membrane ◽  
Biological Processes ◽  
Scanning Calorimetry ◽  
Environmentally Sustainable ◽  
Production Of Hydrogen

Hydrogen is expected to play an important role as a clean, reliable and renewable energy source. A key challenge is the production of hydrogen in an economically and environmentally sustainable way on an industrial scale. One promising method of hydrogen production is via biological processes using agricultural resources, where the hydrogen is found to be mixed with other gases, such as carbon dioxide. Thus, to separate hydrogen from the mixture, it is challenging to implement and evaluate a simple, low cost, reliable and efficient separation process. So, the aim of this work was to develop a polymeric membrane for hydrogen separation. The developed membranes were made of polysulfone via phase inversion by a controlled evaporation method with 5 wt % and 10 wt % of polysulfone resulting in thicknesses of 132 and 239 micrometers, respectively. Membrane characterization was performed using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), atomic force microscopy (AFM), and ASTM D882 tensile test. Performance was characterized using a 23 factorial experiment using the time lag method, comparing the results with those from gas chromatography (GC). As a result, developed membranes exhibited dense microstructures, low values of RMS roughness, and glass transition temperatures of approximately 191.75 °C and 190.43 °C for the 5 wt % and 10 wt % membranes, respectively. Performance results for the given membranes showed a hydrogen selectivity of 8.20 for an evaluated gas mixture 54% hydrogen and 46% carbon dioxide. According to selectivity achieved, H2 separation from carbon dioxide is feasible with possibilities of scalability. These results are important for consolidating hydrogen production from biological processes.

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