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  • Author or Editor: Lu Zheng x
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Abstract

Calycanthine is an important class of alkaloids extracted and isolated from the roots, leaves, flowers and fruits of Chimonanthus praecox. In this work, the UPLC-MS/MS method was used for determination of calycanthine in rat plasma, and the pharmacokinetics in rats were investigated. Midazolam was used as an internal standard (IS), and methanol precipitation method was used to pretreatment the rat plasma samples. Chromatographic separation was achieved on a UPLC BEH C18 (50 × 2.1 mm, 1.7 μm) column with the mobile phase of methanol- 0.1% formic acid aqueous solution with gradient elution. Multiple reaction monitoring (MRM) mode with positive ionization was applied for quantitative analysis, m/z 347.3 → 246.7 and 326.2 → 291.4 for calycanthine and IS, respectively. The results indicated that within the range of 1–200 ng/mL, linearity of calycanthine in rat plasma was good (r > 0.995), and the lower limit of quantification (LLOQ) was 1 ng/mL. Accuracy range was between 90.6 and 109.4%, precision (RSD) of calycanthine was less than 14%. The matrix effect was between 97.9% and 105.4%, the recovery was better than 85.6%. The developed UPLC-MS/MS method was successfully applied in the pharmacokinetics of calycanthine in rats after oral and intravenous administration. The absolute bioavailability of the calycanthine was 37.5% in rats.

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Abstract

Crystallization behaviors and spherulitic morphology of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] with different 4-hydroxybutyrate (4HB) molar fraction were investigated by differential scanning calorimetry and polarized optical microscopy. Crystallization behaviors of P(3HB-co-4HB) are significantly affected by 4HB molar fraction. The melting temperature (T m), glass transition temperature (T g), and crystallinity (X c) decrease with the increase of 4HB molar fraction. Banded spherulites are observed in poly (3-hydroxybutyrate) (PHB) and P(3HB-co-4HB) copolymers. The band spacing decreases with the increase of 4HB molar fraction. The morphology and growth rate of the spherulites strongly depend on 4HB molar fraction and the crystallization temperatures. The introduction of 4HB unit can inhibit the emergence of cracks in PHB spherulites.

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Abstract  

In this paper the modification of Ahrland's method for the determination of free acidity of uranyl solutions has been studied. The modified method gave satisfactory results because the free acidity of original saturated ammonium sulphate solution was considered. Relative error of the determination was less than 5%. Moreover this modification method is suitable for uranyl solutions containing relatively high concentrations of uranium and ratio of uranium to acid.

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Abstract

Calycanthine is an important class of alkaloids extracted and isolated from the roots, leaves, flowers and fruits of Chimonanthus praecox. In this work, the UPLC-MS/MS method was used for determination of calycanthine in rat plasma, and the pharmacokinetics in rats were investigated. Midazolam was used as an internal standard (IS), and methanol precipitation method was used to pretreatment the rat plasma samples. Chromatographic separation was achieved on a UPLC BEH C18 (50 × 2.1 mm, 1.7 μm) column with the mobile phase of methanol- 0.1% formic acid aqueous solution with gradient elution. Multiple reaction monitoring (MRM) mode with positive ionization was applied for quantitative analysis, m/z 347.3 → 246.7 and 326.2 → 291.4 for calycanthine and IS, respectively. The results indicated that within the range of 1–200 ng/mL, linearity of calycanthine in rat plasma was good (r > 0.995), and the lower limit of quantification (LLOQ) was 1 ng/mL. Accuracy range was between 90.6 and 109.4%, precision (RSD) of calycanthine was less than 14%. The matrix effect was between 97.9% and 105.4%, the recovery was better than 85.6%. The developed UPLC-MS/MS method was successfully applied in the pharmacokinetics of calycanthine in rats after oral and intravenous administration. The absolute bioavailability of the calycanthine was 37.5% in rats.

Open access
Acta Chromatographica
Authors: Haiya Wu, Mengrou Lu, Jiamin He, Miaoling Huang, Aote Zheng, Meiling Zhang, Congcong Wen and Jufen Ye

In this study, a precise, rapid, and accurate ultra-performance liquid chromatography–tandem mass spectrometer (UPLC–MS/MS) method for the quantitation of O-demethyl nuciferine in mouse blood was developed, and pharmacokinetics of O-demethyl nuciferine was studied for the first time after sublingual injection and gavage. The study was performed with an UPLC ethylene bridged hybrid (UPLC BEH) (2.1 mm × 50 mm, 1.7 μm) column at 30 °C, using diazepam as the internal standard (IS). The mobile phase consisted of acetonitrile–10 mmol/L ammonium acetate (containing 0.1% formic acid), with a flow rate of 0.4 mL/min for 4 min run time. Multiple reaction monitoring (MRM) modes of m/z 282.1→219.0 for O-demethyl nuciferine and m/z 296.2→265.1 for IS were utilized to conduct quantitative analysis. Protein in mouse blood was directly precipitated with acetonitrile for sample preparation. The linear range was 1–500 ng/mL with r > 0.995, and the lower limits of quantification (LLOQ) was 1 ng/mL. The intra- and inter-day precision of O-demethyl nuciferine in mouse blood were RSD < 14% and RSD < 15%, respectively.r The accuracy ranged from 89.0% to 110.7%, with a recovery higher than 88.9%, while the matrix effect was between 103.1% and 108.7%. We further applied this UPLC–MS/MS method to the pharmacokinetic study on O-demethyl nuciferine after sublingual injection and gavage and determined the bioavailability to be 6.4%.

Open access

In this paper, we present detailed experimental and modeling studies of a recently developed triphasic segmented flow millireactors for rapid nanoparticle-catalyzed gas–liquid reactions. We first present detailed observations of the hydrodynamics and flow regimes in a pseudo-biphasic mode of operation, which enable the design and selection of optimal operating conditions for the triphasic millireactor. We particularly focus on and analyze the presence of wetting films of the organic phase on the reactor walls at high flow speeds, a consequence of the phenomenon of forced wetting, which is a key ingredient for optimal reactor performance. Next, we describe the development of a simple phenomenological model, incorporating the key mass transport steps that accurately captures the observed experimental trends for the rhodium nanoparticle (RhNP) catalyzed hydrogenation of a model substrate (1-hexene). We further discuss and analyze the consequences of this model.

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Aegilops sharonensis (Sharon goatgrass) is a valuable source of novel high molecular weight glutenin subunits, resistance to wheat rust, powdery mildew, and insect pests. In this study, we successfully hybridized Ae. sharonensis as the pollen parent to common wheat and obtained backcross derivatives. F1 intergeneric hybrids were verified using morphological observation and cytological and molecular analyses. The phenotypes of the hybrid plants were intermediate between Ae. sharonensis and common wheat. Observations of mitosis in root tip cells and meiosis in pollen mother cells revealed that the F1 hybrids possessed 28 chromosomes. Chromosome pairing at metaphase I of the pollen mother cells in the F1 hybrid plants was low, and the meiotic configuration was 25.94 I + 1.03 II (rod). Two pairs of primers were screened out from 150 simple sequence repeat markers, and primer WMC634 was used to identified the presence of the genome of Ae. sharonensis. Sequencing results showed that the F1 hybrids contained the Ssh genome of Ae. sharonensis. The sodium dodecyl sulfate polyacrylamide gel electrophoresis profile showed that the alien high molecular weight glutenin subunits of Ae. sharonensis were transferred into the F1 and backcross derivatives. The new wheat-Ae. sharonensis derivatives that we have produced will be valuable for increasing resistance to various diseases of wheat and for improving the quality of bread wheat.

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Acta Chromatographica
Authors: Qinghua Weng, Lianguo Chen, Luxin Ye, Xiaojie Lu, Zheng Yu, Congcong Wen, Yichuan Chen and Gang Huang

The aim of this study was to establish a rapid, sensitive, and selective ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method to quantify the concentrations of licochalcone A and applicate the technique to its pharmacokinetic study. Analytes were separated on an UPLC ethylene bridged hybrid (BEH) C18 column (2.1 mm × 50 mm, 1.7 μm). The mobile phase was consisted of acetontrile and 0.1% formic acid with a flow rate of 0.4 mL/min in a gradient elution mode. Multiple-reaction monitoring (MRM) was carried out in a negative mode for licochalcone A (m/z 337.2 → 119.7) and the internal standard (IS) (m/z 609.0 → 300.9). The linearity of licochalcone A was great from 0.53 to 530 ng/mL. The lower limit of quantification and the lower limit of detection were 0.53 ng/mL and 0.26 ng/mL, respectively. The intra-day precision was less than 14%, and the inter-day precision was no more than 11%. The accuracy was from 91.5% to 113.9%, the recovery was over 90.5%, and the matrix effect was between 84.5% and 89.7%. The results of stability were in an acceptable range. The bioavailability was only 3.3%, exhibiting poor absorption. The developed method was successfully applicable for determining the concentrations of licochalcone A and its pharmacokinetic study.

Open access