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971.
Hydrochlorothiazide is a common diuretic antihypertensive drug of the thiazide family. Its poor aqueous solubility is one of the reasons for its limited bioavailability after oral administration. This work aimed at the development of a hydrochlorothiazide:β-cyclodextrin (HTZ:β-CD) pharmaceutical composition in order to improve water solubility and bioavailability of the drug. The HTZ:β-CD complexes were prepared by three different methods: spray-drying, freeze-drying and fluid bed. Complexes were characterized by thermal analysis, Fourier transform-infrared (FTIR) spectroscopy, powder X-ray diffractometry, NMR (2D-ROESY), scanning electron microscopy (SEM), particle analysis and intrinsic dissolution. The findings reveal that three binary systems prepared presented better solubility results in comparison with free HTZ. Increased diuretic effect was observed to HTZ:β-CD obtained by fluid bed in comparison to free drug in rats. Results taken together suggest that pharmacological effect of HTZ in complex was increased by solubility improvement promoted by cyclodextrin. 相似文献
972.
973.
Zanotti KJ Silva GL Creeger Y Robertson KL Waggoner AS Berget PB Armitage BA 《Organic & biomolecular chemistry》2011,9(4):1012-1020
Fluoromodules are complexes formed upon the noncovalent binding of a fluorogenic dye to its cognate biomolecular partner, which significantly enhances the fluorescence quantum yield of the dye. Previously, several single-chain, variable fragment (scFv) antibodies were selected from a yeast cell surface-displayed library that activated fluorescence from a family of unsymmetrical cyanine dyes covering much of the visible and near-IR spectrum. The current work expands our repertoire of genetically encodable scFv-dye pairs by selecting and characterizing a group of scFvs that activate fluorogenic violet-absorbing, blue-fluorescing cyanine dyes, based on oxazole and thiazole heterocycles. The dye binds to both yeast cell surface-displayed and soluble scFvs with low nanomolar K(d) values. These dye-protein fluoromodules exhibit high quantum yields, approaching unity for the brightest system. The promiscuity of these scFvs with other fluorogenic cyanine dyes was also examined. Fluorescence microscopy demonstrates that the yeast cell surface-displayed scFvs can be used for multicolor imaging. The prevalence of 405 nm lasers on confocal imaging and flow cytometry systems make these new reagents potentially valuable for cell biological studies. 相似文献
974.
A fast, high-yielding synthesis of diaryl ethers with use of mild and metal-free conditions has been developed. The scope includes bulky ortho-substituted diaryl ethers, which are difficult to obtain by metal-catalyzed protocols. Halo-substituents, racemization-prone amino acid derivatives, and heteroaromatics are also tolerated. The methodology is expected to be of high utility in the synthesis of complex molecules and in the pharmaceutical industry. 相似文献
975.
This work reports the development of a simple method for the quantitative determination of aromatic and aliphatic low-molecular-mass aldehydes (LMMAs) as disinfection by-products (DBPs) in indoor swimming pool waters after chlorination with a simplified SPE sample treatment. The method is based on the continuous in situ derivatization/preconcentration of the aldehydes with 2,4-dinitrophenylhydrazine (DNPH) on a Lichrolut EN column in the presence of β-CD. After elution, the 2,4-dinitrophenylhydrazine derivatives were separated on an RP-C(18) analytical column using gradient of ACN-water at 60-80%. The optimized sample treatment described here allowed the direct analysis of large volumes of water in order to improve the sensitivity of the method; LODs in the 60-120 ng/L range were achieved for aromatic LMMAs by using a volume of 50 mL of water, precision being 7.5% or better at a concentration level of 5 μg/L. These results indicate that the ensuing method is a useful choice for the determination of LMMAs in water samples that provides better results than reported LC alternatives in terms of the LOD (except for MS/MS detection), sample requirements for analysis and cost. 相似文献
976.
Pedroso MP Ferreira EC Hantao LW Bogusz S Augusto F 《Journal of separation science》2011,34(13):1547-1554
Combining qualitative data from the chromatographic structure of 2-D gas chromatography with flame ionization detection (GC×GC-FID) and that from gas chromatography-mass spectrometry (GC/MS) should result in a more accurate assignment of the peak identities than the simple analysis by GC/MS, where coelution of analytes is unavoidable in highly complex samples (rendering spectra unsuitable for qualitative purposes) or for compounds in very low concentrations. Using data from GC×GC-FID combined with GC/MS can reveal coelutions that were not detected by mass spectra deconvolution software. In addition, some compounds can be identified according to the structure of the GC×GC-FID chromatogram. In this article, the volatile fractions of fresh and dehydrated pineapple pulp were evaluated. The extraction of the volatiles was performed by dynamic headspace extraction coupled to solid-phase microextraction (DHS-SPME), a technique appropriate for slurries or solid matrices. Extracted analytes were then analyzed by GC×GC-FID and GC/MS. The results obtained using both techniques were combined to improve compound identifications. 相似文献
977.
Martins A Alves da Silva ML Faria S Marques AP Reis RL Neves NM 《Macromolecular bioscience》2011,11(7):978-987
A specially designed electroconductive collector enables the electrospinning of P-NFM composed of areas of parallel/uniaxially aligned fibers and areas of random/orthogonal nanofiber distribution. The biological relevance of P-NFM is demonstrated using hBMSCs as an autologous cell source. The structures induce cell orientation along the uniaxially aligned fibers, mainly during earlier culturing periods under basal and osteogenic differentiation conditions. The microtopography of the P-NFM also controls the deposition of mineralized extracellular matrix along the pre-defined fiber direction. Genotypic characterization confirms the successful differentiation into the osteogenic lineage. 相似文献
978.
Silva SG Morales-Rubio A de La Guardia M Rocha FR 《Analytical and bioanalytical chemistry》2011,401(1):365-371
A new procedure for spectrofluorimetric determination of free and total glycerol in biodiesel samples is presented. It is
based on the oxidation of glycerol by periodate, forming formaldehyde, which reacts with acetylacetone, producing the luminescent
3,5-diacetyl-1,4-dihydrolutidine. A flow system with solenoid micro-pumps is proposed for solution handling. Free glycerol
was extracted off-line from biodiesel samples with water, and total glycerol was converted to free glycerol by saponification
with sodium ethylate under sonication. For free glycerol, a linear response was observed from 5 to 70 mg L−1 with a detection limit of 0.5 mg L−1, which corresponds to 2 mg kg−1 in biodiesel. The coefficient of variation was 0.9% (20 mg L−1, n = 10). For total glycerol, samples were diluted on-line, and the linear response range was 25 to 300 mg L−1. The detection limit was 1.4 mg L−1 (2.8 mg kg−1 in biodiesel) with a coefficient of variation of 1.4% (200 mg L−1, n = 10). The sampling rate was ca. 35 samples h−1 and the procedure was applied to determination of free and total glycerol in biodiesel samples from soybean, cottonseed,
and castor beans. 相似文献
979.
André Luiz Flores Trajano Pires da Nóbrega Neto 《Journal of Pure and Applied Algebra》2011,215(6):1440-1442
Let p be an odd prime. A family of (p−1)-dimensional over-lattices yielding new record packings for several values of p in the interval [149…3001] is presented. The result is obtained by modifying Craig’s construction and considering conveniently chosen Z-submodules of Q(ζ), where ζ is a primitive pth root of unity. For p≥59, it is shown that the center density of the (p−1)-dimensional lattice in the new family is at least twice the center density of the (p−1)-dimensional Craig lattice. 相似文献
980.
Alireza M. Ashtiani Paulo A. V. Ferreira 《Journal of Optimization Theory and Applications》2011,149(2):411-419
The paper addresses the problem of maximizing a sum of products of positive and concave real-valued functions over a convex
feasible set. A reformulation based on the image of the feasible set through the vector-valued function which describes the
problem, combined with an adequate application of convex analysis results, lead to an equivalent indefinite quadratic extremum
problem with infinitely many linear constraints. Special properties of this later problem allow to solve it by an efficient
relaxation algorithm. Some numerical tests illustrate the approach proposed. 相似文献