scholarly journals Zero-Order or First-Order Release Kinetics of Water-in-Oil-in-Water(W/O/W) Multiple Emulsions of Lipiodol Dependent on the Types of Surfactants.

1992 ◽  
Vol 40 (10) ◽  
pp. 2860-2863 ◽  
Author(s):  
Shan-Yang LIN ◽  
Wing-Yiu LUI
Keyword(s):  
Release Kinetics ◽  
Zero Order ◽  
First Order ◽  
Multiple Emulsions ◽  
Oil In Water ◽  
Order Release ◽  
Kinetics Of

scholarly journals In vitro release kinetics study of Esomeprazole Magnesium Trihydrate tablet available in Bangladesh and comparison with the originator brand (Nexium®)

1970 ◽  
Vol 4 (1) ◽  
pp. 79-83
Author(s):  
Shimul Halder ◽  
Madhabi Lata Shuma ◽  
Abul Kalam Lutful Kabir ◽  
Abu Shara Shamsur Rouf
Keyword(s):  
Release Kinetics ◽  
Zero Order ◽  
Kinetics Study ◽  
Medium Ph ◽  
First Order ◽  
Order Release ◽  
Originator Brand ◽  
E6 And E7 ◽  
Esomeprazole Magnesium

The main aim of present investigation was to study the dissolution pattern of most commercially available formulations of Esomeprazole in Bangladesh. Commercially available ten national brands and originator brand of esomeprazole magnesium trihydrate tablets were studied in simulated gastric medium (pH 1.2) for first 15 minutes and simulated intestinal medium (pH 6.8) for next 30 minutes time period using USP reference dissolu-tion apparatus (Type II). No brands met the dissolution pattern like the originator brand (E1). But three brands (E3, E6 and E7) were found to be very close to it in terms of dissolution pattern. One brand E11 was found to be sub-standard compared to originator one. Drug release profiles were analyzed for zero order, first order and Higuchi equation to reveal the release kinetics perspective of Esomeprazole magnesium trihydrate enteric coated tablets. It was found that first order kinetics was predominant for E1 (Originator Brand). Zero order and Higuchi release kinetics was predominant release mechanism than first order release kinetics for E2, E4 and E11. First order release kinetics was predominant for rest of the brands (E3, E5, E6, E7, E8, E9 and E10). It was found that drug release of those brands followed moderately diffusion method and concentration dependant from the dosage form. Among all of these locally manufactured Esomeprazole brands E3, E6 and E7 showed compatible dissolution pattern and release kinetics compared with the originator brand. Key words: In vitro dissolution; Market preparations; Kinetics study; Esomeprazole; National brand; Originator brand. DOI: http://dx.doi.org/10.3329/sjps.v4i1.8875 SJPS 2011; 4(1): 79-83

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

Strontium modified biocements with zero order release kinetics

Biomaterials ◽  
2008 ◽  
Vol 29 (35) ◽  
pp. 4691-4697 ◽  
Author(s):  
Mohammad Hamdan Alkhraisat ◽  
Claus Moseke ◽  
Luis Blanco ◽  
Jake E. Barralet ◽  
Enrique Lopez-Carbacos ◽  
...  
Keyword(s):  
Release Kinetics ◽  
Zero Order ◽  
Order Release ◽  
Zero Order Release

Supercritical Fluid Deposition of Ruthenium Thin Films: A Kinetic Study

2007 ◽  
Vol 992 ◽  
Author(s):  
Christos F. Karanikas ◽  
James J. Watkins
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Deposition Temperature ◽  
Zero Order ◽  
Measurable Effect ◽  
Deposition Rates ◽  
Reaction Pressure ◽  
Deposition Kinetics ◽  
First Order ◽  
Kinetics Of

AbstractThe kinetics of the deposition of ruthenium thin films from the hydrogen assisted reduction of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(1,5-cyclooctadiene)ruthenium(II), [Ru(tmhd)2cod], in supercritical carbon dioxide was studied in order to develop a rate expression for the growth rate as well as to determine a mechanism for the process. The deposition temperature was varied from 240°C to 280°C and the apparent activation energy was 45.3 kJ/mol. Deposition rates up to 30 nm/min were attained. The deposition rate dependence on precursor concentrations between 0 and 0.2 wt. % was studied at 260°C with excess hydrogen and revealed first order deposition kinetics with respect to precursor at concentrations lower then 0.06 wt. % and zero order dependence at concentrations above 0.06 wt. %. The effect of reaction pressure on the growth rate was studied at a constant reaction temperature of 260°C and pressures between 159 bar to 200 bar and found to have no measurable effect on the growth rate.

Fabrication and Release Kinetics of Liposomes Containing Leuprolide Acetate

2021 ◽  
Vol 7 (1) ◽  
pp. 35-38
Author(s):  
Sudipta Das ◽  
Arnab Samanta ◽  
Koushik Bankura ◽  
Debatri Roy ◽  
Amit Nayak
Keyword(s):  
Drug Release ◽  
Release Kinetics ◽  
In Vitro Release ◽  
Zero Order ◽  
Leuprolide Acetate ◽  
Lipid Film ◽  
In Vitro Drug Release ◽  
Liposomal Formulations ◽  
Kinetics Of

The present work is focused on the preparation and in vitro release kinetics of liposomal formulation of Leuprolide Acetate. In this work, “Thin Lipid Film Hydration Method” was used for preparation of Leuprolide Acetate loaded liposomes. Prepared liposomal formulations of Leuprolide acetate was evaluated by drug entrapment study, in-vitro drug release kinetics and stability studies. The percentage drug entrapment of Leuprolide acetate for F1 and F2 formulations were found to be 78.14 ± 0.67 and 66.70 ± 0.81% respectively. In-vitro drug release study of liposomal formulations had shown zero order release pattern. Regression co-efficient (R2) value of Zero order kinetics for F1 and F2 formulations were 0.9912 and 0.9676 respectively. After storing formulations for 1 month, stability testing was done at 40C.It was found that all batches were stable. These liposomal formulations of Leuprolide acetate can be formulated for parenteral application to treat prostate cancer and in women, to treat symptoms of endometriosis (overgrowth of uterine lining outside of the uterus) or uterine fibroids.

scholarly journals Kinetics of K release from soils of Brazilian coffee regions: effect of organic acids

2008 ◽  
Vol 32 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Vladimir Antônio Silva ◽  
Giuliano Marchi ◽  
Luiz Roberto Guimarães Guilherme ◽  
José Maria de Lima ◽  
Francisco Dias Nogueira ◽  
...  
Keyword(s):  
Release Kinetics ◽  
Kinetic Studies ◽  
Release Rates ◽  
First Order ◽  
Potassium Release ◽  
Minas Gerais State ◽  
Soil Clay ◽  
Extractant Solution ◽  
Kinetics Of ◽  
K Release

Kinetic studies on soil potassium release can contribute to a better understanding of K availability to plants. This study was conducted to evaluate K release rates from the whole soil, clay, silt, and sand fractions of B-horizon samples of a basalt-derived Oxisol and a sienite-derived Ultisol, both representative soils from coffee regions of Minas Gerais State, Brazil. Potassium was extracted from each fraction after eight different shaking time periods (0-665 h) with either 0.001 mol L-1 citrate or oxalate at a 1:10 solid:solution ratio. First-order, Elovich, zero-order, and parabolic diffusion equations were used to parameterize the time dependence of K release. For the Oxisol, the first-order equation fitted best to the experimental data of K release, with similar rates for all fractions and independent of the presence of citrate or oxalate in the extractant solution. For all studied Ultisol fractions, in which K release rates increased when extractions were performed with citrate solution, the Elovich model described K release kinetics most adequately. The highest potassium release rate of the Ultisol silt fraction was probably due to the transference of "non-exchangeable" K to the extractant solution, whereas in the Oxisol exchangeable potassium represented the main K source in all studied fractions.

Protodemercuration of organomercuric chlorides. II. Heterocyclic mercuric chlorides

1965 ◽  
Vol 18 (10) ◽  
pp. 1513 ◽  
Author(s):  
RD Brown ◽  
AS Buchanan ◽  
AA Humffray
Keyword(s):  
Chloride Ion ◽  
Ion Pair ◽  
Zero Order ◽  
Hydrogen Ion ◽  
First Order ◽  
Entropy Effects ◽  
Kinetics Of ◽  
Complex Anions ◽  
Dominant Influence ◽  
Electron Effects

The kinetics of protodemercuration, or displacement of the HgCl group by hydrogen, have been measured for 2- and 3-furyl, 2-thienyl, and 2-selenophenylmercuric chlorides. The reactions of these compounds with aqueous alcoholic hydrochloric acid were first order in hydrogen ion, first order in RHgC1, and zero order in chloride ion, when the latter was present at concentrations less than 0.1M. At 70�, the relative rates were: 3-furyl, 1; 2-furyl, 27; 2-thienyl, 11; 2-seleno- phenyl, 25. At higher chloride concentrations, the rate increases; this is discussed in terms of formation of complex anions of the type RHgCl32- and in terms of H+Cl- ion pair attack. The dominant influence of entropy effects in the case of furan compounds emphasizes the danger of trying to account for observed relative rates in terms of π-electron effects alone.

scholarly journals   Copper release kinetics: Effect of two extractants and wheat (Triticum aestivum L.) rhizosphere

2012 ◽  
Vol 58 (No. 10) ◽  
pp. 471-476 ◽  
Author(s):  
H.R. Motaghian ◽  
A.R. Hosseinpur
Keyword(s):  
Citric Acid ◽  
Release Kinetics ◽  
Calcareous Soils ◽  
Triticum Aestivum L ◽  
First Order ◽  
Rhizosphere Soils ◽  
Copper Release ◽  
Successive Extraction ◽  
The Mean ◽  
Kinetics Of

The greenhouse experiment was performed to determine Cu release characteristics in the bulk and the rhizosphere of some calcareous soils using rhizobox. The kinetics of Cu release in the bulk and the rhizosphere soils were determined by successive extraction with diethylenetriaminepentaacetic acid-triethanolamine (DTPA-TEA) and 10 mmol/L citric acid in a period of 1 to 504 h at 25 ± 1°C. The results of kinetics study showed that Cu extracted using DTPA-TEA in the rhizosphere soils was significantly (P < 0.01) lower than the bulk soils, while Cu extracted using citric acid in the rhizosphere soils was significantly (P < 0.01) higher than the bulk soils. The mean of released Cu after 504 h using DTPA-TEA were 8.59 and 7.46 mg/kg in the bulk and the rhizosphere soils, respectively. The mean release of Cu after 504 h using citric acid was 14.73 and 16.05 mg/kg in the bulk and the rhizosphere soils, respectively. Release kinetics of Cu in two extractants conformed fairly well to parabolic diffusion, power function, and first order equations. The results of correlation analysis illustrated that a significant correlation between Cu desorption after 504 h with citric acid and Cu concentration in wheat was found (r = 0.96 and r = 0.90 in the rhizosphere and the bulk soils, respectively, P < 0.01). Therefore, application of 10 mmol/L citric acid extractant would be recommended in the future study on the kinetics of release of Cu in calcareous soils.  

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