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排序方式: 共有71条查询结果,搜索用时 15 毫秒
31.
Preparation of dry powder inhalation by surface treatment of lactose carrier particles 总被引:4,自引:0,他引:4
Iida K Hayakawa Y Okamoto H Danjo K Leuenberger H 《Chemical & pharmaceutical bulletin》2003,51(1):1-5
An attempt was made to produce carrier particles for dry powder inhalations by the surface treatment of lactose particles with aqueous ethanol solution. Drug/carrier powder mixtures were prepared consisting of lactose carriers with different particle surface properties and micronized salbutamol sulfate. These powder mixtures were aerosolized by Spinhaler, and in vitro deposition properties of salbutamol sulfate were evaluated by twin impinger. The degree of adhesion between drug particles and carrier particles was determined by the ultracentrifuge separation method. In addition, the air jet sieve method was used to evaluate characteristics of the separation of drug particles from carrier particles in airflow. The average adhesion force (F50) between the surface-treated lactose carrier and drug particles was significantly lower than that of powder mixed with the untreated lactose carrier, indicating that the degree of separation (T50) of drug particles from carrier particles was improved when surface-treated lactose carrier was used. This resulted in an improvement of in vitro inhalation properties. 相似文献
32.
Leuenberger M Nyfeler P Moret HP Sturm P Huber C 《Rapid communications in mass spectrometry : RCM》2000,14(16):1543-1551
We have developed a new inlet system for a gas sample isotope ratio mass spectrometer (IRMS). It is based on the well-known open split design from the gas chromatography/mass spectrometry (GC/MS) system due to its simplicity. The advantages over the conventional double inlet system with the metal bellows design include an improved reproducibility mainly due to a highly controllable pressure and temperature adjustment, a markedly lowered memory effect due to an uninterrupted gas flow through the ion source which limits adsorption/desorption processes on surfaces, and a single inlet capillary circumventing problems of asymmetrical behavior of sample and reference inlet paths. Furthermore, sample consumption is of the same order as for conventional measurements (i.e. about 0.4 mmol per hour), of which however only 2 &mgr;mol/h is used for the actual isotope ratio determination since the major gas amount acts as a gas flow seal against the atmosphere, corresponding to a 100-200 fold overkill. This may be improved in future systems. Copyright 2000 John Wiley & Sons, Ltd. 相似文献
33.
Hans Georg Wilhelm Leuenberger Walter Boguth Erich Widmer Reinhard Zell 《Helvetica chimica acta》1976,59(5):1832-1849
Synthesis of optically active natural carotenoids and structurally related compounds. I. Synthesis of the chiral key compound (4R, 6R)-4-hydroxy-2,2,6-trimethylcyclohexanone. A technical synthesis of (4R, 6R)-4-hydroxy-2,2,6-trimethylcyclohexanone ( 7 ) starting from the readily available oxo-isophorone ( 2 ) is described. 7 is an ideal precursor for the synthesis of naturally occurring, optically active hydroxylated carotenoids (e.g. zeaxanthin, cryptoxanthin and structurally related compounds). Chirality is introduced at C(6) by a stereoselective fermentative hydrogenation of the double bond using baker's yeast as the biocatalyst. Thereafter the carbonyl group at C(4) is reduced selectively and stereospecifically by chemical methods to the corresponding alcohol. Chemical reduction is preferably carried out by hydrogenation in the presence of a nickel catalyst or using triisobutylaluminium as the reducing agent. Stability, stereochemistry and physical properties of 7 and the stereoisomers thereof are discussed. 相似文献
34.
Helene Wolleb Francesco Bonina Megan Udry Stefan Reber Nicole Blumer Daniel Leuenberger Gabriel Schäfer 《Helvetica chimica acta》2023,106(10):e202300124
An efficient three-step synthesis of (1R)-1-(4-bromophenyl)-2,2,2-trifluoroethan-1-amine hydrochloride ( 1 ) starting from inexpensive and readily available starting materials was developed. The sequence features a highly diastereoselective trifluoromethylation of a chiral sulfinimine using the Rupert–Prakash reagent TMSCF3 in combination with K3PO4 as an initiator. The diastereomeric purity of the resulting sulfinamide was further improved by direct precipitation of the desired diastereomer from the reaction mixture upon addition of water. The chiral auxiliary was then removed under acidic conditions, resulting in the isolation of chiral benzylamine 1 as its hydrochloride salt in 71 % overall yield and excellent purity (LC/MS: >99 % a/a; e.r.=99 : 1). 相似文献
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M Goese W Eisenreich E Kupfer P Stohler W Weber H G Leuenberger A Bacher 《The Journal of organic chemistry》2001,66(13):4673-4678
Fermentation experiments with Streptomyces toxytricini were performed using (5Z,8Z)-[10,11,12,12-(2)H]tetradeca-5,8-dienoic acid or a mixture of [2,2-(2)H(2)]- and [8,8,8-(2)H(3)]octanoic acid as supplements. (2)H NMR and mass spectroscopy confirmed the incorporation of (5Z,8Z)-[10,11,12,12-(2)H]tetradeca-5,8-dienoic acid into the C(13) side chain as well as into the C(6) side chain of lipstatin. Moreover, deuterium was incorporated into the C(6) side chain of lipstatin from the 8-position but not from the 2-position of octanoate. The data establish that the beta-lactone moiety of lipstatin is formed by condensation of a C(8) and a C(14) fatty acid with a concomitant exchange of the H-2 atoms of the C(8) fatty acid. 相似文献
38.
Journal of Nanoparticle Research - 相似文献
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40.
Marc Ramuz David Leuenberger Lukas Bürgi 《Journal of Polymer Science.Polymer Physics》2011,49(1):80-87
Evanescent coupling is used to couple light from an organic Lambertian emitter into a single‐mode planar waveguide. A polymer light emitting diode pumps a photoluminescent layer located directly on top of the waveguide. At the out‐coupling grating stage, a fully organic mini‐spectrometer compatible with monolithical integration on optical bio chips has been developed. It consists of a single‐mode waveguide with integrated diffraction grating and a dense array of polymer photodiodes as sensing element. An overall spectral resolution of down to 5 nm has been achieved with the integrated optoelectronic system. As a proof of principle the fully organic optical device has been used in combination with a fluidic system to demonstrate an absorption‐based bio‐test with mouse immunoglobulin G. In a further step towards low‐cost and disposable lab‐on‐chip biosensors, the mentioned organic building blocks have been combined with a surface plasmon stack integrated directly onto the single mode waveguide. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010 相似文献