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71.
Taher Boukhris Malika Lahiani-Skiba Damien Martin Mohamed Skiba 《Journal of inclusion phenomena and macrocyclic chemistry》2013,75(3-4):323-332
The purpose of this study was to develop a new oral cyclosporine A (CsA) formulation free of surfactant cremophor using cyclodextrin terpolymers (P-αβ-CD, P-βγ-CD and P-αγ-CD) as excipients in attempt to enhance its stability, dissolution rate and eliminate surfactant side effects. Two spray-dried dispersions (SDDs) containing poorly water-soluble CsA were prepared with either P-αβ-CD, P-βγ-CD or P-αγ-CD using water ( $ F_{{{\text{H}}_{2} {\text{O}}}} $ ) and ethanol (F EOH) via spray-drying technique and characterized by scanning electron microscopy, powder X-ray diffraction, particle size distribution, circular dichroism (CD) and nuclear magnetic resonance along with the dissolution study which was compared to Neoral® and Sandimmune®. The results showed an interaction between CsA and P-αβ-CD, P-βγ-CD and P-αγ-CD without secondary structure change of CsA. The order of the CsA release from the terpolymers was ranked as follows: P-αγ-CD/CsA ( $ F_{{{\text{H}}_{2} {\text{O}}}} $ ) = Neoral® > P-βγ-CD/CsA ( $ F_{{{\text{H}}_{2} {\text{O}}}} $ ) > P-αβ-CD/CsA ( $ F_{{{\text{H}}_{2} {\text{O}}}} $ ) > P-αγ-CD/CsA (F EOH) > Sandimmune® > P-αβ-CD/CsA (F EOH) > P-βγ-CD/CsA (F EOH). The results of ( $ F_{{{\text{H}}_{2} {\text{O}}}} $ ) could be explained by hydrophilisation and absence of crystallinity of CsA while maintaining part of its crystallinity in the case of formulations (F EOH). In summary, developed SDD formulations P-αγ-CD/CsA ( $ F_{{{\text{H}}_{2} {\text{O}}}} $ ) revealed same dissolution profile as Neoral® and better than Sandimmune®. These systems seem to be stable to carry cyclosporine and release it, while preserving structure and thus, potentially, also maintaining cyclosporine activity. 相似文献
72.
Fréderic Bounoure Malika Lahiani-Skiba Cécile Barbot Abdussalam Sughir Eric Mallet Soizic Jezequel Ludovic Didier Philippe Arnaud Mohamed Skiba 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):191-195
Metopimazine (MPZ) is an antiemetic drug used by oral and rectal administration. A transdermal delivery system of MPZ may
present a great advantage for the treatment of nausea and vomiting to improve therapeutic adhesion. MPZ is a lipophilic drug
with poor water solubility. Partially methyled β cyclodextrin (PMβ-CD) was tested to enhance percutaneous absorption of MPZ.
Complex MPZ/cyclodextrin was characterized by Higushi’s phase solubility, Fourier transform infrared spectroscopy (FTIR) and
differential scanning calorimetry (DSC) analyses and MPZ octanol partition coefficient was also determinated. The permeation
of free MPZ and inclusion complex through pig skin were investigated using Franz’s cells. Four concentrations of cyclodextrins,
0, 5, 10 and 20% were tested. Partition coefficient was depending on pH of the solution. At pH 5.5, MPZ ionization increased
the hydrophily (0.71) and at pH 10.3, non-ionized MPZ was the dominant form (591). The solubility of MPZ increased with the
concentration of PMβ-CD and the phase solubility diagram is an Ap type. The used characterization analyses demonstrated the formation of an inclusion complex and this complex improved percutaneous
absorption of MPZ. No MPZ flux was detected for a suspension of MPZ and it was more important with MPZ hydrochloride, 0.177 ± 0.044 μg/h/cm2.
Flux was increased to 0.570 ± 0.058 μg/h/cm2 with a concentration of 20%. The use of cyclodextrin with MPZ hydrochloride increased
also the percutaneous absorption with 0.549 ± 0.175 μg/h/cm2 for a concentration of 5%, 0.435 ± 0.031 μg/h/cm2 for a concentration
of 10% and 0.474 ± 0.054 μg/h/cm2 for a concentration of 20%. This study shows that PMβ-CD improves percutaneous penetration
of MPZ. But the absorption is not enough to allow a therapeutic effect. Cyclodextrin complex increases MPZ solubility and
this bioavailability at the skin surface, and cyclodextrin may also modify the barrier propriety of skin. 相似文献
73.
Julie Dutet Malika Lahiani-Skiba Ludovic Didier Soizic Jezequel Fréderic Bounoure Cécile Barbot Philippe Arnaud Mohamed Skiba 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):203-209
Purpose Ternary solid dispersions were prepared in order to estimate the effect of a double hydrophilization by cyclodextrins and
PEG 6000 on nimesulide apparent characteristics. Ternary solid dispersions of nimesulide, cyclodextrins and PEG 6000 were
characterized using DSC, FT-IR, dissolution studies and evaluating the bioavailability in rats.
Methods Ternary solid dispersions were prepared either using native powders or using a preformed inclusion complex of nimesulide and
cyclodextrin. Inclusion complexes and pure drug were used as references. Circulating nimesulide was measured out in rat plasma
after orally administration of our different products (ternary solid dispersions, inclusion complexes and pure drug).
Results An improvement of the nimesulide dissolution rate was obtained with inclusion complexes and ternary solid dispersion. In rat
plasma, inclusion complexes and ternary solid dispersion improved T
max.
Conclusions A second hydrophilization of inclusion complexes by PEG 6000 does not allow to achieve better results concerning nimesulide
concentration in rat plasma or in dissolution studies than with inclusion complexes alone. 相似文献
74.
Pelzer K Hävecker M Boualleg M Candy JP Basset JM 《Angewandte Chemie (International ed. in English)》2011,50(22):5170-5173
75.
Curran DP Solovyev A Makhlouf Brahmi M Fensterbank L Malacria M Lacôte E 《Angewandte Chemie (International ed. in English)》2011,50(44):10294-10317
Boranes are widely used Lewis acids and N-heterocyclic carbenes (NHCs) are popular Lewis bases, so it is remarkable how little was known about their derived complexes until recently. NHC-boranes are typically readily accessible and many are so stable that they can be treated like organic compounds rather than complexes. They do not exhibit "borane chemistry", but instead are proving to have a rich chemistry of their own as reactants, as reagents, as initiators, and as catalysts. They have significant potential for use in organic synthesis and in polymer chemistry. They can be used to easily make unusual complexes with a broad spectrum of functional groups not usually seen in organoboron chemistry. Many of their reactions occur through new classes of reactive intermediates including borenium cations, boryl radicals, and even boryl anions. This Review provides comprehensive coverage of the synthesis, characterization, and reactions of NHC-boranes. 相似文献
76.
Glass RS Schöneich C Wilson GS Nauser T Yamamoto T Lorance E Nichol GS Ammam M 《Organic letters》2011,13(11):2837-2839
Methionine residues have been shown to function as efficient "hopping" sites in long-range electron transfer in model polyprolyl peptides. We suggest that a key to this ability of methionine is stabilization of the transient sulfur radical cation by neighboring proline amide participation. That is, in a model system a neighboring pyrrolidine amide lowers the oxidation potential of the thioether by over 0.5 V by formation of a two-center three-electron SO bond. 相似文献
77.
An efficient synthesis of 11-selena and 11-tellura steroids bearing a pyridine as an A ring was achieved via an intramolecular Diels-Alder cycloaddition of o-quinodimethanes, which were generated from a 3-azabicyclo[4.2.0]octa-1,3,5-trien-7-one ketal. The major isomer matches the trans-anti-trans ring configuration of natural products. Finally, the vinyl groups of the synthesized 11-hetero steroids have been oxidized by the Wacker process in good yields. The characteristic 1H and 13C NMR spectroscopic features of the synthesized compounds are reported. 相似文献
78.
Tlach BC Tomlinson AL Bhuwalka A Jeffries-El M 《The Journal of organic chemistry》2011,76(21):8670-8681
In an effort to design new electron-deficient building blocks for the synthesis of conjugated materials, a series of new trans-benzobisoxazoles bearing halogen or alkynyl substituents at the 4,8-positions was synthesized. Additionally, the impact of these modifications on the optical and electronic properties was investigated. Theoretical calculations predicted that the incorporation of various alkynes can be used to tune the energy levels and band gaps of these small molecules. The targeted 4,8-disubstituted benzobisoxazoles were easily prepared in good yields using a two-step reaction sequence: Lewis acid catalyzed orthoester cyclization followed by Sonogashira cross-coupling. The experimentally determined HOMO values for these 4,8-disubstituted benzobisoxazoles ranged from -4.97 to -6.20 eV and showed reasonable correlation to the theoretically predicted values, with a percent deviation that ranged from 2.4-12.8%. However, the deviation between actual and predicted HOMO values was reduced to less than 3.5% when the theoretical values were extrapolated to the long-chain limit and compared to copolymers containing the 4,8-disubstituted benzobisoxazoles. Collectively, these results indicate that these 4,8-disubstituted trans-benzobisoxazoles can be used for the synthesis of new conjugated materials with electronic properties that are variable and predictable. 相似文献
79.
Malika Ammam Bineta Keita Louis Nadjo Israel‐Martyr Mbomekalle Michelle D. Ritorto Travis M. Anderson Wade A. Neiwert Craig L. Hill Jan Fransaer 《Electroanalysis》2011,23(6):1427-1434
The electrochemical behavior of two manganese (Mn)‐substituted polyoxoanions, the dissymmetrical Dawson sandwich‐type [MnII4(H2O)2(H4AsW15O56)2]18? and the Keggin sandwich banana‐shaped [((MnIIOH2)MnII2PW9O34)2(PW6O26)]17? is investigated. At pH 5, the oxidation of the MnII‐centers results in one oxidation wave for [MnII4(H2O)2(H4AsW15O56)2]18? and two oxidation waves for [((MnIIOH2)MnII2PW9O34)2(PW6O26)]17?. To the best of our knowledge, presence of the second Mn‐based wave is rarely observed in the electrochemistry of Mn‐containing polyoxometalates. Deposition of Mn‐oxides electrocatalysts for dioxygen reduction is noticed by cyclic voltammetry, which can be distinguished by the significant positive shift in potentials of the dioxygen reduction reaction. 相似文献
80.