A Comparison of Dynamic Systems Models of Gastrointestinal Kinetics of Controlled Release Multimatrix System 5-Aminosalicylic Acid (5-ASA), LialdaTM with pH-dependent, Delayed Release 5-ASA (AsacolTM)

2010 ◽  
Vol 105 ◽  
pp. S475
Author(s):  
Deepak Parakkal ◽  
Matthew Thorpe ◽  
Sarah Paver ◽  
Eli Ehrenpreis ◽  
Bruce Hannon
2008 ◽  
Vol 103 ◽  
pp. S434
Author(s):  
Srini Tenjarla ◽  
Vallente Romasanta ◽  
Adeyinka Abinusawa

2016 ◽  
Author(s):  
Galina Ivanovna Popova ◽  
◽  
Yuliya Nikolaevna Prilepskaya ◽  

1980 ◽  
Vol 45 (5) ◽  
pp. 1601-1607 ◽  
Author(s):  
Marie Stiborová ◽  
Sylva Leblová

Iodoacetate inactivates rape alcohol dehydrogenase (ADH, EC 1.1.1.1). The inactivation rate follows the kinetics of the first order, is pH-dependent, and decreases below pH 7.5. Besides irreversible alkylation of the sulfhydryl groups of the enzyme iodoacetate also forms a reversible complex with rape ADH. The coenzyme (NAD) and its analogs (ATP, ADP, AMP) competitively protect the enzyme against alkylation; o-phenanthroline also protects the enzyme against alkylation yet noncompetitively with respect to iodoacetate. Imidazole and o-phenanthroline compete with one another for binding to the protein molecule of rape ADH. Whereas o-phenanthroline decreases the inactivation rate imidazole increases the rate of iodoacetate inactivation.


Author(s):  
Félix M. Pereira ◽  
Adilson R. Gonçalves ◽  
André Ferraz ◽  
Flávio T. Silva ◽  
Samuel C. Oliveira

2015 ◽  
Vol 585 ◽  
pp. 52-63 ◽  
Author(s):  
Rishu Jain ◽  
Rajesh Kumar ◽  
Sandeep Kumar ◽  
Ritika Chhabra ◽  
Mukesh Chand Agarwal ◽  
...  

2015 ◽  
Vol 185 ◽  
pp. 361-379 ◽  
Author(s):  
Ana Marta Diniz ◽  
Nuno Basílio ◽  
Hugo Cruz ◽  
Fernando Pina ◽  
A. Jorge Parola

A multistate molecular dyad containing flavylium and viologen units was synthesized and the pH dependent thermodynamics of the network completely characterized by a variety of spectroscopic techniques such as NMR, UV-vis and stopped-flow. The flavylium cation is only stable at acidic pH values. Above pH ≈ 5 the hydration of the flavylium leads to the formation of the hemiketal followed by ring-opening tautomerization to give the cis-chalcone. Finally, this last species isomerizes to give the trans-chalcone. For the present system only the flavylium cation and the trans-chalcone species could be detected as being thermodynamically stable. The hemiketal and the cis-chalcone are kinetic intermediates with negligible concentrations at the equilibrium. All stable species of the network were found to form 1 : 1 and 2 : 1 host : guest complexes with cucurbit[7]uril (CB7) with association constants in the ranges 105–108 M−1 and 103–104 M−1, respectively. The 1 : 1 complexes were particularly interesting to devise pH responsive bistable pseudorotaxanes: at basic pH values (≈12) the flavylium cation interconverts into the deprotonated trans-chalcone in a few minutes and under these conditions the CB7 wheel was found to be located around the viologen unit. A decrease in pH to values around 1 regenerates the flavylium cation in seconds and the macrocycle is translocated to the middle of the axle. On the other hand, if the pH is decreased to 6, the deprotonated trans-chalcone is neutralized to give a metastable species that evolves to the thermodynamically stable flavylium cation in ca. 20 hours. By taking advantage of the pH-dependent kinetics of the trans-chalcone/flavylium interconversion, spatiotemporal control of the molecular organization in pseudorotaxane systems can be achieved.


2020 ◽  
Vol 190 ◽  
pp. 105566 ◽  
Author(s):  
Chou Wu ◽  
Xianfen Lou ◽  
Aimin Huang ◽  
Min Zhang ◽  
Lin Ma

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