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RISS 인기검색어
- 검색키워드
- 저자 : Navid Mostoufi (검색결과 3 건)
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Sustained release coating of ibuprofen pellets at Wurster fluidization: statistical approach
Hossein Sedighikamal,Reza Zarghami,Parissa Khadiv-Parsi,Navid Mostoufi 한국약제학회 2015 Journal of Pharmaceutical Investigation Vol.45 No.4
The Wurster fluidization coating is recognized in many pharmaceutical industries for its precise film coating onto particulate materials such as pellets, granules, and powders. The current work focused on some process variables to study sustained release behavior of ibuprofen pellets at a lab-scale Wurster fluidized bed coater. Applying design of experiment, the effect of mean pellets size (dp), air flow rate (Qa), coating solution flow rate (Qs), and drying time duration (td) were investigated statistically on the mean dissolution time (MDT) of ibuprofen pellets. Results in analysis of variance illustrated that a decrease in dp make rising of MDT due to decreasing the ibuprofen diffusivity in the media owing to trapping role of ethyl cellulose. It was also found increasing of Qs resulted in extending of MDT due as the coating solution deposited on the pellets surface was increased. While the td did not play an important role on the MDT, the MDT was increased by Qa because of pellets circulation within the bed.
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Characterization of flow properties of pharmaceutical pellets in draft tube conical spout-fluid beds
Mohammad Foroughi-Dahr,Rahmat Sotudeh-Gharebagh,Navid Mostoufi 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.68 No.-
Experimental studies of the hydrodynamic performance of the draft tube conical spout-fluid bed (DCSF) were conducted using pharmaceutical pellets. The experiments were carried out in a DCSF consisted of two sections: (a) a conical section with the cross section of 120 mm × 250 mm and the height of 270 mm, (b) a cylindrical section with the diameter of 250 mm and the height of 600 mm. The flow characteristics of solids were investigated with a high speed camera and a pezoresistive absolute pressure transducer simultaneously. These characteristics revealed different flow regimes in the DCSF: packed bed at low gas velocities, fluidized bed in draft tube at higher gas velocities until minimum spouting, and spouted bed. The stable spouting was identified by the presence of two dominant frequencies of the power spectrum density of pressure fluctuation signature: (i) the frequency band 6–9 Hz and (ii) the frequency band 12–15 Hz. The pressure drops across the draft tube as well as the annulus measured in order to better recognize the flow structure in the DCSF. It was observed that the pressure drop across the draft tube, the pressure drop across the annulus, and the minimum spouting velocity increase with the increase in the height of draft tube and distance of the entrainment zone, but with the decrease in the distributor hole pitch. Finally, this study provided novel insight into the hydrodynamic of DCSF, particularly minimum spouting and stable spouting in the DCSF which contains valuable information for process design and scale-up of spouted bed equipment.
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Farhad Karimi,Rahmat Sotudeh-Gharebagh,Reza Zarghami,Mojgan Abbasi,Navid Mostoufi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.5
Wetted rice particles were dried in a fluidized bed and the corresponding passive acoustic emissions signals (AES) were recorded at a given frequency to study the drying phenomena and bed hydrodynamic changes as well. The results show that the end time of the constant rate zone and the end of the falling rate can be determined from the variation of standard deviation and kurtosis of AES, respectively. Frequency domain analysis was also used to quantify the moisture content of solids. For this end, the original signal was decomposed into ten sub-signals, and it was found that the energy of the 4th sub-signal can be correlated with the moisture content. The results show that the acoustic emission measurement is applicable as a practical method for on-line condition monitoring of drying process in fluidized bed dryers.
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