Xianhua Zhang

Enantiomeric separation of β-blockers by HPLC using (R)-1-naphthylglycine and 3,5-dinitrobenzoic acid as chiral stationary phase

Abstract Direct liquid chromatographic separations of the enantiomers of metoprolol and bisoprolol have been developed, using (R)-1-naphthylglycine and 3,5-dinitrobenzoic acid as chiral stationary phase (CSP). The separations were achieved in a normal phase system employing a mobile phase containing n-hexane, 1,2-dichloroethane and methanol. Column efficiency was strongly dependent on the composition of the mobile phase. The eluent contents of methanol and of 1,2-dichloroethane were optimized, and so was flow-rate and column temperature. Under the optimal conditions, linear responses for (R)-metoprolol and (S)-metoprolol are obtained in the range of 0.079–1.38 and 0.015–5.80 mg/ml, with detection limits of 0.008 and 0.002 mg/ml, respectively. As for bisoprolol, the linear ranges of (R)-isomer and (S)-isomer are 0.05–1.31 and 0.02–1.00 mg/ml with detection limits of 0.001 and 0.008 mg/ml, respectively. The relative standard deviation (R.S.D.) of each enantiomer did not exceed 0.90%. The method has been successfully applied to the determination of enantiomers in pharmaceuticals.

Detection of different quorum‐sensing signal molecules in a virulent Edwardsiella tarda strain LTB‐4

Aims:  The aim of this study was to elucidate the potential quorum‐sensing (QS) signal molecules of an emerging pathogen (Edwardsiella tarda strain LTB‐4) of cultured turbot (Scophthalmus maximus).

Simultaneous quantification of EVT201, a novel partial positive allosteric GABAA receptor modulator, and its two metabolites in human plasma by UHPLC/MS/MS

HighlightsEVT201 is a novel partial GABAA receptor agonist to treat insomnia.A sensitive and accurate UHPLC‐MS/MS method was developed to determine EVT201 and its two metabolites in human plasma.The method was successfully applied to the sample analysis of a Phase I clinical trial. ABSTRACT A sensitive, accurate and rapid UHPLC–MS/MS method was developed and validated for the simultaneous determination of EVT201 and its two metabolites, Ro46‐1927 and Ro18‐5528, in human plasma. D6‐EVT201 was used as the internal standard (IS). Plasma samples were extracted using ethyl acetate after being alkalized with saturated sodium carbonate solution. Chromatographic separation was carried out on an Acquity BEH C18 column (2.1 × 50 mm, 1.7 &mgr;m) with a gradient mobile phase at a flow‐rate of 0.50 mL/min. The analytical run time was 5.5 min. For mass spectrometric detection, multiple reaction monitoring (MRM) was used. The MRM ion transitions were m/z 373.2 → 58.0 for EVT201, m/z 359.2 → 316.1 for Ro46‐1927, m/z 291.2 → 274.1 for Ro18‐5528 and m/z 379.3 → 64.0 for the IS. The linear range was 0.2–200 ng/mL for each analyte, with a correlation coefficient (r) over 0.9900. The intra‐/inter‐ precision was within 7.9% and 4.5% for EVT201, 13.2% and 6.3% for Ro46‐1927, 3.7% and 4.1% for Ro18‐5528. For the accuracy, the relative bias of intra‐/inter‐ run was no more than 6.4% and 4.6% for EVT201, 9.4% and 7.9% for Ro46‐1927, −6.9% and −7.5% for Ro18‐5528. The validated method was successfully applied to the analysis of more than 1500 samples from a Phase I clinical trial. The incurred sample reanalysis (ISR) of 146 samples from the study was evaluated and the results met the acceptance criteria. It indicated that the method could be used for the pharmacokinetic study of EVT201.

Using of method and result of LUCC study in field of Chinese medicine resources

The contradiction between the ecological environment, natural resources and the development of social and economic has become increasingly conspicuous. Land resources are the physical basis of Chinese medicine resources and habitat of the medicinal organisms. Meanwhile, land resources are also the bridge and tie between Chinese medicine resources and environment that include society and natural environment. Chinese medicine resources exist in the multiplexed system that constituted by the natural ecological environment and the human social environment. So the sustainable use of Chinese medicine resources includes the Chinese medicine resources itself and the nature environment and society environment that exist in. For the sustainable use of the Chinese medicine resources, it is necessary to study the change of Chinese medicine resources, the change of environment and the relationship between the Chinese medicine resources and environment that exist in. The technology method and result of land use and land cover change study, that can be use in the field of Chinese medicine resources change study. It can help researchers show the history, process, reason, and forecast the trend and result of Chinese medicine resources change.

Hormesis and its application in medicinal plant growing

Hormesis describes the low-dose stimulation and high-dose inhibition phenomena for all kind lives under toxicity environment. This paper generalized hormesis of medicinal plant on grow and metabolite after introducing the concept and study state of hormesis and analyzing hormesis mechanism and its significance. It points out that hormesis can be well used for medicinal plants growth, including increasing the metabolise, giving a dereaction for cultivated field chosen, guiding the agriculture management during the cultivation and improving the anti-stress.