Calcium sulfide-organosilicon complex for sustained release of H2S in strongly acidic wastewater: Synthesis, mechanism and efficiency

2021 ◽  
pp. 126745
Author(s):  
Feng Zhu ◽  
Xingyun Hu ◽  
Linghao Kong ◽  
Xianjia Peng
Keyword(s):  
Sustained Release ◽  
Calcium Sulfide ◽  
Synthesis Mechanism ◽  
Acidic Wastewater

The dissolution characteristics of calcium sulfide and utilization as a precipitation agent in acidic wastewater effluent treatment

2011 ◽  
Vol 63 (12) ◽  
pp. 2860-2866 ◽  
Author(s):  
J. N. Zvimba ◽  
J. Mulopo ◽  
M. De Beer ◽  
L. Bologo ◽  
M. Mashego
Keyword(s):  
Metal Removal ◽  
Wastewater Effluent ◽  
Effluent Treatment ◽  
Molar Ratio ◽  
Calcium Sulfide ◽  
Solution Ph ◽  
Solution Conductivity ◽  
Ph Dependent ◽  
Acidic Wastewater ◽  
Wastewater Effluents

The dissolution characteristics of CaS in the presence of CO2 has been investigated by monitoring sulfide speciation, solution conductivity and pH during dissolution. The sulfide speciation associated with CaS dissolution was utilized for metal precipitation from acidic wastewater effluents. The mechanism involved in the dissolution process was observed to be pH-dependent, characterized by increased solution conductivity as the HS− species becomes dominant in solution in the form of the Ca(HS)2 complex. The replacement of HS− by CO32− in the Ca(HS)2 complex triggered CaCO3 precipitation and H2S stripping and this was characterized by decreased solution pH and conductivity. The sulfide to total metal molar ratio was observed to have an effect on the pH and therefore sulfide speciation as well as extent of metal removal. The utilization of CaS in the treatment of acidic wastewater effluents demonstrated complete metal removal, with the potential of a pH-controlled selective metal removal and recovery.

1558: Local Injection of Sustained-Release Antiandrogen Formulation into a Target Prostatic Site: An Experimental Study

2007 ◽  
Vol 177 (4S) ◽  
pp. 515-515
Author(s):  
Nobuyuki Goya ◽  
Kotara Gotanda ◽  
Yasuko Tomizawa ◽  
Hiroshi Toma
Keyword(s):  
Experimental Study ◽  
Sustained Release ◽  
Local Injection

Effects of release modifier on Carvedilol release from Kollidon SR based matrix

2012 ◽  
Vol 1 (8) ◽  
pp. 186 ◽  
Author(s):  
Urmi Das ◽  
Mohammad Salim Hossain
Keyword(s):  
Drug Release ◽  
Sustained Release ◽  
Microcrystalline Cellulose ◽  
Matrix Tablets ◽  
Dissolution Time ◽  
Release Mechanism ◽  
Matrix Tablet ◽  
Weight Variation ◽  
The Matrix ◽  
Tablet Formulations

<p>Sustained release Carvedilol matrix tablets constituting Kollidon SR were developed in this study in an attempt to investigate the effect of release modifiers on the release profile of Carvedilol from matrix. Three matrix tablet formulations were prepared by direct compression of Kollidon SR in combination with release modifier (HPMC and Microcrystalline Cellulose) and magnesium stearate. Tablets containing only Kollidon SR with the active ingredient demonstrated a rapid rate of drug release. Incorporation of HPMC in the matrix tablet prolonged the release of drug but incorporation of Microcrystalline Cellulose showed superimposable release pattern with an initial burst effect as confirmed by mean dissolution time and Higuchi release rate data. After 7 hours of dissolution, Carvedilol release from the matrix systems were 91.42%, 83.41%, from formulation F1 and F2 respectively. Formulation F3 exhibited 100 % release at 4 hours. All the tablet formulations showed acceptable pharmaco-technical properties and complied with the in-house specifications for tablet weight variation, friability, hardness, thickness, and diameter. Prepared tablets also showed sustained release property for carvedilol. The drug release mechanism from the matrix tablets of F1 and F2 was found to be followed by Fickian and F3 by Non-Fickian mechanism.</p><p>DOI: <a href="http://dx.doi.org/10.3329/icpj.v1i8.11095">http://dx.doi.org/10.3329/icpj.v1i8.11095</a></p> <p>International Current Pharmaceutical Journal 2012, 1(8): 186-192</p>

Formulation Optimization of Sustained Release Resinate Microcapsules of Tramadol Hydrochloride by Using 3/2 Factorial Design

2017 ◽  
Vol 6 (2) ◽  
pp. 57
Author(s):  
Kamble Ravindra K. ◽  
Chauhan Chetan S. ◽  
Kamble Priyadarshani R. ◽  
Naruka Pushpendra S.
Keyword(s):  
Drug Delivery ◽  
Ion Exchange ◽  
Sustained Release ◽  
Factorial Design ◽  
Linear Regression Analysis ◽  
Extended Period ◽  
Multiple Linear Regression Analysis ◽  
Water Soluble ◽  
Tramadol Hydrochloride ◽  
Release Drug

The main aim of the present work was to develop the microcapsules of tramadol hydrochloride for the oral sustained release drug delivery. Tramadol hydrochloride a BCS class I drug a centrally acting synthetic analgesic was complexed with Indion 254 ion exchange resin. The microcapsules were prepared by encapsulating the prepared resinates by o/o solvent evaporation technique. In the investigation 32 full factorial design was used to investigate the joint influence of two formulation variable amount of eudragit RS 100 and plasticized PEG 400. The results of multiple linear regression analysis indicated that for obtaining a sustained release drug delivery the optimum concentrations of both the plasticizer and coating solution to be used. The factorial models were used to prepare optimized microcapsules and optimized formulations showed sustained release profiles for the extended period of more than 12 hrs. From the present investigations concluded that resinate microcapsules of highly water soluble drug can provide controlled release of drug for extended period.Key Words: Tramadol hydrochloride, ion exchange resinate, microcapsules, sustained release

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