Preparation of pure U3O8 from crude sodium diuranate by intermediate complex formation

1957 ◽  
Vol 45 (1) ◽  
pp. 20-23 ◽  
Author(s):  
N. S. Krishnaprasad ◽  
V. V. Dadape
Keyword(s):  
Complex Formation ◽  
Intermediate Complex

scholarly journals Cytochrome P-450 complex formation in rat liver by the antibiotic tiamulin.

1996 ◽  
Vol 40 (1) ◽  
pp. 50-54 ◽  
Author(s):  
R F Witkamp ◽  
S M Nijmeijer ◽  
A S van Miert
Keyword(s):  
Complex Formation ◽  
Selective Inhibition ◽  
Farm Animals ◽  
Intermediate Complex ◽  
Metabolic Intermediate ◽  
Dose Dependent ◽  
Cytochrome P 450 ◽  
Related Compounds ◽  
Substrate Concentrations ◽  
Different Doses

Tiamulin is a semisynthetic diterpene antibiotic frequently used in farm animals. The drug has been shown to produce clinically important--often lethal--interactions with other compounds. It has been suggested that this is caused by a selective inhibition of oxidative drug metabolism via the formation of a cytochrome P-450 metabolic intermediate complex. In the present study, rats were treated orally for 6 days with tiamulin at two different doses: 40 and 226 mg/kg of body weight. For comparison, another group received 300 mg of triacetyloleandomycin (TAO) per kg, which is equivalent to the 226-mg/kg tiamulin group. Subsequently, microsomal P-450 contents, P-450 enzyme activities, metabolic intermediate complex spectra, and P-450 apoprotein concentrations were assessed. In addition, effects on individual microsomal P-450 activities were studied in control microsomes at different tiamulin and substrate concentrations. In the rats treated with tiamulin, a dose-dependent complex formation as evidenced by its absorption spectrum and an increase in cytochrome P-4503A1/2 contents as assessed by Western blotting (immunoblotting) were found. The effects were comparable to those of TAO. Tiamulin induced microsomal P-450 content, testosterone 6 beta-hydroxylation rate, erythromycin N-demethylation rate, and the ethoxyresorufin O-deethylation activity. Other activities were not affected or decreased. When tiamulin was added to microsomes of control rats, the testosterone 6 beta-hydroxylation rate and the erythromycin N-demethylation were strongly inhibited. It is concluded that tiamulin is a potent and selective inducer-inhibitor of cytochrome P-450. Though not belonging to the macrolides, the compound produces an effect on P-450 similar to those of TAO and related compounds.

In-vivo kinetics of the interaction between midazolam and erythromycin in rats, taking account of metabolic intermediate complex formation

2001 ◽  
Vol 53 (5) ◽  
pp. 643-651 ◽  
Author(s):  
Sayuri Takedomi ◽  
Hirotami Matsuo ◽  
Katsuhiro Yamano ◽  
Hisakazu Ohtani ◽  
Yasufumi Sawada
Keyword(s):  
Complex Formation ◽  
Intermediate Complex ◽  
Metabolic Intermediate ◽  
In Vivo Kinetics ◽  
Kinetics Of

Kinetics and Mechanism of the Oxidation of Oxyacids of Phosphorus by Benzimidazolium Dichromate

2011 ◽  
Vol 36 (4) ◽  
pp. 352-360 ◽  
Author(s):  
Rakesh Kumar ◽  
Dinesh Panday ◽  
Seema Kothari
Keyword(s):  
Complex Formation ◽  
Oxidation State ◽  
Kinetics And Mechanism ◽  
Intermediate Complex

Oxidation of some lower oxyacids of phosphorus by benzimidazolium dichromate results in the formation of the corresponding oxyacids containing phosphorus in a higher oxidation state, via an intermediate complex formation.

Sulfenamide Accelerated Sulfur Vulcanization of Natural Rubber in Presence and Absence of Dicumyl Peroxide

1970 ◽  
Vol 43 (6) ◽  
pp. 1311-1326 ◽  
Author(s):  
S. P. Manik ◽  
S. Banerjee
Keyword(s):  
Complex Formation ◽  
Stearic Acid ◽  
Natural Rubber ◽  
Methyl Iodide ◽  
Intermediate Complex ◽  
Radical Mechanism ◽  
Dicumyl Peroxide ◽  
Sulfur Vulcanization ◽  
Cross Links ◽  
Presence And Absence

Abstract Sulfuration by CBS acceleration both in presence and absence of ZnO and stearic acid with or without DCP has been studied in detail. It is observed that CBS increases the rate of DCP decomposition and decreases the crosslinking maxima due to DCP—ultimately leading to zero cross links with high amounts of CBS. In accordance with the observed sulfur decrease, free MBT formation, combined sulfur as MS etc., a predominantly radical mechanism has been presented, presumably not proceeding through intermediate complex formation. In mixes containing DCP together with sulfur, CBS, ZnO, and stearic acid crosslinks are found to be formed nearly additively, further confirmed by methyl iodide treatment of vulcanizates. Attempts have been made to interpret the results in terms of radical and polar mechanisms.

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