13C-CPMAS and1H-NMR Study of the Inclusion Complexes ofβ-Cyclodextrin with Carvacrol, Thymol, and Eugenol Prepared in Supercritical Carbon Dioxide

2004 ◽  
Vol 1 (9) ◽  
pp. 1354-1366 ◽  
Author(s):  
Emanuela Locci ◽  
Simona Lai ◽  
Alessandra Piras ◽  
Bruno Marongiu ◽  
Adolfo Lai
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Inclusion Complexes ◽  
Nmr Study ◽  
Supercritical Carbon

NMR study of vinylpyrrolidone polymerization in supercritical carbon dioxide

2009 ◽  
Vol 428 (2) ◽  
pp. 246-249 ◽  
Author(s):  
A. A. Samoilenko ◽  
L. N. Nikitin ◽  
A. M. Lopatin ◽  
I. S. Ionova ◽  
Al. Al. Berlin ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Nmr Study ◽  
Supercritical Carbon

Enhancement of aqueous solubility of itraconazole by complexation with cyclodextrins using supercritical carbon dioxide

2005 ◽  
Vol 83 (10) ◽  
pp. 1833-1838 ◽  
Author(s):  
Ibrahim Shehatta ◽  
Ali Hassan Al-Marzouqi ◽  
Baboucarr Jobe ◽  
Ali Dowaidar
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Stability Constant ◽  
Inclusion Complexes ◽  
Driving Forces ◽  
Aqueous Solubility ◽  
Phase Solubility ◽  
Static Mode ◽  
The Stability ◽  
Supercritical Carbon

The formation of inclusion complexes between itraconazole, a highly hydrophobic drug, and α-, β-, γ-, and hydroxylpropyl-β-cyclodextrin (HP-β-CD) were assessed using phase-solubility techniques. The solubility of itraconazole increased as a function of cyclodextrin concentration showing an AL phase diagram indicating the formation of soluble complexes with 1:1 stoichiometry. The Gibbs free energies of transfer of the drug from aqueous solution to the cavity of cyclodextrin are negative and increase in magnitude with increasing cyclodextrin concentration. The solubility of itraconazole, as well as the stability constant of its complex with HP-β-CD, are found to be affected by the pH of the medium. The HP-β-CD cavity was found to have a greater affinity for the unionized itraconazole than the protonated one. It was found that the interaction between the drug and the cyclodextrin is weakened as the medium becomes more apolar by the addition of methanol. Also, the size of the cavity of the cyclodextrins plays an important role in the association process. Furthermore, the thermodynamic parameters of the complexation process were calculated, by monitoring the isothermic solubility diagrams of itraconazole–HP-β-CD and itraconazole–β-CD at various temperatures, to gain information on the driving forces for the formation of inclusion complexes. Drug formulations of itraconazole were prepared by complexation of the drug into different cyclodextrins using supercritical carbon dioxide in a static mode. The effects of cyclodextrins on the prepared inclusion complexes were studied and characterized by differential scanning calorimetry.Key words: cyclodextrin, itraconazole, inclusion complex, solubility, stability constant.

Diffusion of Water in Liquid and Supercritical Carbon Dioxide:  An NMR Study

2003 ◽  
Vol 107 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Bin Xu ◽  
Kaz Nagashima ◽  
Joseph M. DeSimone ◽  
Charles S. Johnson
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Nmr Study ◽  
Supercritical Carbon
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