Summary A new, highly sensitive and selective gas chromatography method, using radiochemical detection (GC-DR) was developed for the
selective determination of3H-labelled deramciclane and its N-desmethyl metabolite in dog plasma. Inter-day accuracy and precision, as well as system
suitability of the GC-RD method was investigated during the method validation. The calibration curve was proved to be linear
(r=0.9986) in a wide concentration range (13–1000 ngeqv mL−1)
The lower limit of quantitation (LLOQ) was 13.7 ngeqv mL−1, and the limit of the detection (LOD) was 1 ngeqv mL−1.
Using this new GC-RD method, plasma levels of3H-labelled deramciclane and its metabolite were determined in dogs, after the administration of a single 10 mg kg−1 oral dose. Pharmacokinetic curves and the calculated pharmacokinetic parameters were compared to those obtained using a previously
elaborated gas chromatography-nitrogen selective detection method (GC-NPD) and to those obtained by measuring the plasma level
of total radioactivity (liquid scintillation counting, LSC). Pharmacokinetic curves and the calculated pharmacokinetic parameters
obtained with the two different gas chromatography detection methods (NPD and RD) showed good correlation. Comparison of these
results to those acquired by total radioactivity measurement demonstrated that deramciclane was intensively metabolised. Moreover,
the biological half-life (t
12/β
) of the unknown metabolites proved to be more than a magnitude longer than the half-life of the parent compound or that of
N-desmethyl metabolite.
Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997. 相似文献
IR spectroscopy was coupled with the matrix isolation technique to study the molecular complex formed between C3O2 and HCl and its photodissociation. The vibrational frequencies of the complex were compared with those of HCl and C3O2 monomers. For C3O2, a bent structure was characterized in the solid environment.
The vibrational frequencies were calculated in the 4000–400 cm−1 range using an ab initio method at the MP2/6-31G** level for the most stable complex; these frequencies describe the hydrogen interaction with the central carbon atom of C3O2 (T complex). The measured shifts between the vibrational mode frequencies of the complex and monomers were in good agreement with the calculated values.
Broad-band UV irradiation ( > 230 nm) of the T complex leads preferentially to ketene chloride and carbon monoxide. Ketene chloride formation can be explained by the reaction between HCl and the carbene C2O, which results from photo-dissociation at the C=CO bond of C3O2. 相似文献
A homogeneous catalyst, 3-benzyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazolium chloride, for addition of aldehydes to activated double bond, was attached to 20% cross-linked polystyrene-divinylbenzene copolymer. The attached catalysts could be easily removed from the reaction mixture. Polymer-attached thiazolium salts in the presence of triethylamine are active catalysts for addition of aromatic and aliphatic aldehydes to α,β-unsaturated ketones to yield γ-diketones. 相似文献
7-(2-Methoxycarbonylvinyl)-3-hydroxychromones have been synthesized using Heck coupling reaction from the corresponding 7-bromo-3-hydroxychromones. Introduction of the electron acceptor (2-methoxycarbonylvinyl) group at 7-position of 3-hydroxychromone results in a 30-40 nm red shift in absorption and >50 nm red shifts of both bands in emission. This derivatization allowed us to develop dyes with absorption maxima reaching 480 nm and dual emission in the red region of the spectrum. In comparison to the parent dyes, 7-acryl-3-hydroxychromones demonstrate significantly stronger solvatochromism. This is due to the acceptor group at 7-position, which increases the transfer character of the excited state of the dyes. The new dyes are highly prospective for the development of new fluorescent probes in biological research. 相似文献
The biotransformation of bufalin by cell suspension cultures of Platycodon grandiflorus was investigated and two new biotransformed products were obtained,which was 3-epi-telocinobufagin and 3-epi-bufalin-3-O-β-D-glucoside. 相似文献
The use of plastic materials in agriculture causes the serious drawback of huge quantities of waste. The introduction of biodegradable materials, which can be disposed directly into the soil, can be one possible solution to this problem. Biodegradable materials are actually innovative materials; therefore, their physical properties must be evaluated in relation to their functionality during the use in field. In the present research results of experimental tests carried out on biodegradable films used in strawberries protected cultivation are presented. The decay of some relevant physical parameters of biodegradable films during the cultivation period was monitored by laboratory tests (SEM analysis, mechanical tensile tests and infrared reflectance spectroscopy). Infrared spectroscopy clearly indicated that the mechanical degradation starts from the starch component of the material. Tensile tests showed that the value of elongation at break of biodegradable materials decreased in some cases by 300% after 10 days of field application. 相似文献
Summary. N′-Arylacetonitrilimines were generated from acetohydrazonyl chlorides and reacted with mercaptoalkanoic acids forming 4-aryl-5-oxo-3-thiahexanoic
acids. These were cyclized by reaction with dicyclohexyl carbodiimide yielding 2-acetyl-4-aryl-6H-1,3,4-thiadiazin-5-ones.
Received November 13, 2001. Accepted January 9, 2002 相似文献
It was studied by spectroscopy that PSII reaction center complex consisting of three polypeptides, D1, D2 and Cytb559, were purified from PSII particle of CeCl3 treated spinach. The results of the experiment show that Ce3+ could improve the growth of spinach, and accelerate electron transport of PSII particles. Of chl-a of UV-Vis spectrum of
D1/D2/Cytb559 complex, Soret band was blue-shifted by 3 nm and Q band by 2 nm, respectively, and the fluorescence emission
peak was blue-shifted by 5 nm in CeCl3-treated spinach compared with the one in control. By the extended X-ray absorption fine structure (EXAFS) spectroscopy methods,
it has been found that Ce3+ is coordinated with 8 nitrogen atoms in the first coordination shell with Ce-N bond length of 0.253 nm, and Ce3+ with 6 oxygen atoms in the second coordination shell with Ce-O bond length of 0.32 nm. However, the secondary structure of
D1/D2/Cytb559 complex by circular dichroism (CD) spectroscopy has no significant change after CeCl3 treated. It might be that Ce3+ binds to porphyrin rings of chlorophyll and oxygen of amino acid residue of polypeptide in D1/D2/Cytb559 complex, and then
accelerates the primary reaction of PSII, intensifies function of P680+ primary electron donor of D1/D2/Cytb559, but there is little change in conformation of PSII reaction center complex. 相似文献