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81.
Two kinds of thio-heterocyclic fused naphthalene carboxamides, 3a-b, 4a-b, were designed, synthesized and quantitatively evaluated as efficient antitumor and DNA photocleaving agents. Compound 3a or 3b, having the thiophene ring, intercalated into DNA more strongly than compound 4a or 4b, having the thioxanthene ring. Compound 4a or 4b, photocleaved DNA more efficiently than 3a or 3b via superoxide anion. Compound 4a was the strongest inhibitor for P388 (murine leukemia cell), while 3a was the most cytotoxic one against A549 (human lung cancer cell). Each new compound showed stronger DNA photocleaving activity than corresponding naphthalimide. 相似文献
82.
Crommentuyn KM Rosing H Nan-Offeringa LG Hillebrand MJ Huitema AD Beijnen JH 《Journal of mass spectrometry : JMS》2003,38(2):157-166
HIV protease inhibitors are important antiretroviral drugs which have substantially reduced the morbidity and mortality associated with HIV-1 infection. Recent data have shown relationships between plasma concentrations of the protease inhibitors and clinical response, which makes therapeutic drug monitoring valuable. We have developed and validated an assay, using liquid chromatography coupled with electrospray tandem mass spectrometry (LC/MS/MS), for the routine quantification of the six licensed protease inhibitors (amprenavir, indinavir, lopinavir, nelfinavir, ritonavir and saquinavir) and the pharmacologically active nelfinavir metabolite M8 in plasma. The sample pretreatment consisted of protein precipitation with a mixture of methanol and acetronitrile using only 100 microl of plasma. Chromatographic separation was performed on an Inertsil ODS3 column (50 x 2.0 mm i.d., particle size 5 microm), with a quick stepwise gradient using an acetate buffer (pH 5) and methanol, at a flow rate of 0.5 ml min(-1). The analytical run time was 5.5 min. The use of a 96-well plate autosampler allowed batch sizes up to 150 patient samples. The triple-quadrupole mass spectrometer was operated in the positive ion mode and multiple reaction monitoring was used for drug quantification. The method was validated over the concentration ranges 0.01-10 microg ml(-1) for indinavir and saquinavir, 0.1-10 microg ml(-1) for amprenavir, 0.05-10 microg ml(-1) for nelfinavir and ritonavir, 0.1-20 microg ml(-1) for lopinavir and 0.01-5 microg ml(-1) for M8. Saquinavir-d(5) and indinavir-d(6) were used as internal standards. The coefficients of variation were always <10% for both intra-day and inter-day precisions for each compound. Mean accuracies were also between the designated limits (+/-15%). The validated concentration ranges proved to be adequate in daily practice. This robust and fast LC/MS/MS assay is now successfully applied for routine therapeutic drug monitoring and pharmacokinetic studies in our hospital. 相似文献
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85.
Pro-oxidant properties of phenolic antioxidants, which are derived from their iron recycling reactivity, render the traditional deoxyribose degradation assay invalid to assess the hydroxyl radical-scavenging activity in Fenton-type reaction systems. In the present paper, we studied in detail the interactions between iron and phenolic compounds, and established a kinetic deoxyribose method by taking advantage of the distinct difference between the completion time of Fenton reaction and that of the iron-reducing process. With the newly established kinetic method, we investigated the effects of phenolics on hydroxyl radical formation in a Fenton-type system and determined successfully the second rate constants of hydroxyl radical-scavenging reactions. The site-specific and non-site-specific hydroxyl radical-scavenging ability suggested that both direct hydroxyl radical-scavenging potency and iron-chelating capacity accounted for their inhibitory effects on deoxyribose oxidation degradation. This method, more simple, time saving, and applicative than the traditional deoxyribose assay, produces as accurate results (RSD<0.05, with dynamic range from 7.5 to 575 μM) as typical methods, such as radiolysis technology, and may be of significance in evaluating and screen the hydroxyl radical-scavenging antioxidants. 相似文献
86.
87.
Cheguillaume G Buchmann W Desmazières B Tortajada J 《Journal of mass spectrometry : JMS》2004,39(4):368-377
Two model peptides, des-Arg1-bradykinin (DAB) and bradykinin (B), were cationized by Ag+ after their separation by reversed-phase liquid chromatography (RPLC) prior to mass spectrometry (MS). Silver nitrate solution was used as a post-column reagent. The RPLC and MS experimental conditions were optimized using flow injection in order to obtain sufficiently abundant silver adducts to permit MS/MS experiments. The use of water-methanol with 0.1% formic acid as mobile phase allowed a good chromatographic separation of the two peptides with a polymeric stationary phase and sufficiently abundant silver-containing adducts, [M + Ag + H]2+ and [M + 2Ag]2+. The gas-phase dissociation of [DAB + Ag + H]2+ and [DAB + 2Ag]2+ led to interpretable mass spectra during the on-line cationization experiment. Most of the ions obtained by dissociating [DAB + Ag + H]2+ and [DAB + 2Ag]2+ species are silver-containing ions but the ions produced depend on the parent. The ions coming from the dissociation of the doubly charged silver adducts [DAB + Ag + H]2+ or [DAB + 2Ag]2+ are of interest compared with those coming from the singly charged silver species or doubly charged protonated species. The fragmentation of the doubly charged silver adducts provides ions over the entire mass range. Although the presence of several prolines in des-Arg1-bradykinin prevents the formation of some expected ions, the observation of triplets [an-H + Ag]+, [bn-H + Ag]+ and [bn + OH + Ag]+ produced by the dissociation of on-line Ag(+)-cationized peptides could contribute to greater success of automatic sequencing of peptides. 相似文献
88.
A method for the quantification of clindamycin in animal plasma using high-performance liquid chromatography combined with electrospray ionization mass spectrometry (LC/ESI-MS/MS) is presented. Lincomycin is used as the internal standard. The sample preparation includes a simple deproteinization step with trichloroacetic acid. Chromatographic separation is achieved on an RP-18 Hypersil column using gradient elution with 0.01 M ammonium acetate and acetonitrile as mobile phase. Good linearity was observed in the range 0-10 microg ml(-1). The limit of quantification of the method is 50 ng ml(-1) and the limit of detection is 1.3 ng ml(-1). The method was shown out to be of use for pharmacokinetic studies of clindamycin formulations in dogs. 相似文献
89.
90.
Two rapid,sensitive and reliable immunoassay methods,namely competitive indirect enzyme-linked immunosorbent assay(CI- ELISA)and colloidal gold-based immunochromatographic assay(CGIA),were developed to detect ofloxacin(OFL).The linear range of the CI-ELISAwas from 0.5 to 128 ng/mL with a limit of detection(LOD)of 0.35 ng/mL.Good recoveries were obtained in analyzing simulated swine urine samples.The CGIA could accurately estimate OFL at concentrations as low as 10 ng/mL in less than 10 min,and test results were read visually without any instrument. 相似文献