A study on solvent extraction of cerium/III/ ion with 1-/2-pyridylazo/-2-naphthol /PAN or HL/ in chloroform from perchloric acid solution is described. The effect of equilibrium time, the pH of the aqueous phase and the concentration centration of extractant in organic phase on the extraction efficiency of cerium/III/ has been studied. The results show that the mechanism of extraction reaction is 3Ce
CeL3/o/ + 3H
Authors:Zhen Li, Li Yu, Liqiang Zheng, and Fei Geng
In this work, solid lipid nanoparticles (SLN) have been prepared from water-in-oil-in-water double emulsion, using monocaprate as solid lipid, sorbitan monooleate (Span 80) and polyoxyethylene sorbitan monolaurate (Tween 20) as emulsifier, and puerarin as target drug. The morphology of SLN with drug loaded or not was investigated by the transmission electron microscope (TEM). The crystal order and structure of particles were studied by differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD), respectively. The results indicate that the diameters of SLN with puerarin inside are larger than those without drugs. The analysis of WAXD and DSC shows that the state of crystallinity SLN prepared by double emulsion method was worse than that of SLN prepared by microemulsion. And also the drug-loaded SLN presents a less ordered crystallinity than the drug-free SLN. But both the drug-free and drug-loaded SLN exist in an amorphous state. The reasons of the phenomenon have been discussed.
Authors:Zhu Zhaowu, He Jianyu, Zhang Zefu, Zhang Yu, and Zheng Weifang
The kinetics of the reduction of plutonium(IV) by hydroxyurea (HU), a novel salt free reductant, in nitric acid solutions
has been studied. The observed reaction rate can be expressed as: -d[Pu(IV)]/dt=k0[Pu(IV)]2[HU]/[H+]0.9, where k0 = 5853±363 (l1.1.mol-1.1.s-1) at t = 13 °C. The activation energy is about 81.2 kJ/mol. The study also shows that uranium(VI) has no appreciable influence on
the reaction rate. Compared with other organic reductants our experiments indicate that HU is a very fast reductant for plutonium(IV).
8-O-Acetylharpagide is the main active component of the herb Ajuga decumbens, which possesses anti-tumor, anti-virus, and anti-inflammation properties. In this study, ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was used to measure the concentration of 8-O-acetylharpagide in mouse blood, with subsequent investigation of the pharmacokinetics of the drug after intravenous or oral administration. Shanzhiside methyl ester was used as an internal standard, and the acetonitrile precipitation method was used to process the blood samples. Chromatographic separation was achieved using an ultra-performance liquid chromatography ethylene-bridged hybrid (UPLC BEH) column (2.1 mm × 50 mm, 1.7 μm) with a gradient methanol–water mobile phase (containing 0.1% formic acid). The flow rate was 0.4 mL/min, and the elution time was 5.0 min. 8-O-Acetylharpagide was quantitatively measured using electrospray ionization (ESI) tandem mass spectrometry in multiple reaction monitoring (MRM) mode with positive ionization. The result indicated that, within the range of 5–500 ng/mL, the linearity of 8-O-acetylharpagide in mouse blood was satisfactory (r > 0.995), and the lower limit of quantification (LLOQ) was 5 ng/mL. Intra-day precision relative standard deviation (RSD) of 8-O-acetylharpagide in blood was lower than 9%, and the inter-day precision RSD was lower than 13%. The accuracy range was between 94.3% and 107.1%, average recovery was higher than 91.3%, and the matrix effect was between 100.8% and 110.8%. This analytical method was sensitive and fast with good selectivity and was successfully applied to perform pharmacokinetic studies of 8-O-acetylharpagide in mice. The bioavailability of 8-O-acetylharpagide was 10.8%, and the analysis of the primary pharmacokinetic parameters after oral and intravenous administration indicated that 8-O-acetylharpagide had a significant first pass effect after oral administration.
Authors:Shao-Ning Yu, Zheng-Ping Fan, Li Ma, Yan-Zhao Yang, and Bo-Rong Bao
The influence of the concentration of nitric, hydrochloric and phosphoric acids, petroleum sulfoxides (PSO), salting-out agent,
kind of diluent and temperature on the distribution ratio of U(VI) and Th(IV) has been systematically studied. It is found
that the extraction regularity of PSO is similar to that of TBP. The distribution ratio in phosphoric acid is lower, but it
increases with the increase of hydrochloric acid concentration and reaches a high value. The U(VI) exhibits the maximum distribution
ratio at 3–4 mol/l HNO3. The distribution ratio of U(VI) and Th(IV) increases rapidly in the presence of a salting out agent. The extracted compounds
are determined to be UO2(NO3)22PSO and Th(NO3)42PSO. The extraction enthalpies of U(VI) and Th(IV) with PSO were also calculated.
Authors:Meifei Lu, Xiaojie Lu, Zheng Yu, and Congcong Wen
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.
Authors:Lixia Wang, Wanchun Zhu, Dafang Zheng, Xue Yu, Jing Cui, Mingjun Jia, Wenxiang Zhang, and Zhenlu Wang
The reaction of direct transformation of ethanol to ethyl acetate was investigated on reduced Cu/ZrO2 catalysts prepared by a co-precipitation procedure. The catalytic performances of these Cu–Zr mixed oxides were considerably
influenced by changing the molar ratio of Cu to Zr. The highest selectivity to ethyl acetate was found over Cu/ZrO2(1) catalyst (molar ratio of Cu to Zr was 1). A variety of characterization techniques, such as N2 adsorption, XRD, XPS, TPR and NH3-TPD were carried out on the catalysts. The results revealed that the presence of a certain amount of Cu+ species may play very important role in improving the selectivity to ethyl acetate of the Cu/ZrO2 catalysts.
Authors:Fang Geng, Nan Hu, Ji-Fang Zheng, Cheng-Lei Wang, Xin Chen, Jia Yu, and De-Xin Ding
The objective of this study was to evaluate the potential ecological danger and toxic effect of uranium mill tailings leaching
solution (UMTLS) on aquatic animals. UMTLS was identified to contain two radioactive elements, nine heavy metal elements,
and five non-metallic materials. The acute toxicity test indicated that the 1, 12, 24, 48, 72, 96 h LC50 values of UMTLS to the zebrafish were 12.1, 7.1, 4.4, 3.8, 3.4, and 2.9%, respectively. In sub-lethal toxicity tests, superoxide
dismutase, catalase, Na+–K+–ATPase activities, and malondialdehyde content were respectively determined and analyzed in the zebrafish gill, gonad, muscle,
and liver after exposed to four different concentration levels of UMTLS for 7 and 14 days, respectively. The result showed
that the most sensitivity of the antioxidant system in zebrafish tissues in UMTLS was gill, and then decreased in gonad, muscle
and liver respectively. Na+–K+–ATPase activity in the liver and gonad may be considered as a reference biomarker of UMTLS stress. The data in this study
may be valuable that the toxicity of such as the leaching solution of potentially hazardous material was compared with that
of each constituent.
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.
Radiolabeling of biologically active molecules with fac-[188Re(CO)3(H2O)3]+ unit has been of primary interest in recent years. Therefore, we herein report ligands L1−L4 (L1=histidine, L2=nitrilotriacetic acid, L3=2-picolylamine-N,N-diacetic acid, L4=bis(2-pyridymethy)amine) that have been evaluated by radiochemical reactions with fac-[188Re(CO)3(H2O)3]+. These reactions yielded the radioactive complexes of fac-[188Re(CO)3L] (L = L1−L4, 188Re tricarbonyl complexes 1–4), which were identified by HPLC. Complexes 1–4, with log Po/w values ranging from −2.23 to 2.18, were obtained with yields of ≥95% using ligand concentrations within 10−6–10−4M range. Thus, specific activities of 220 GBq/μmol could be achieved. Challenge studies with cysteine and histidine revealed
high stability for all of these radioactive complexes, and biodistribution studies in mice indicated a fast rate of blood
clearance and high rate of total radioactivity excretion occurring primarily through the renal-urinary pathway. In summary,
the ligands L1–L4 are potent chelators for the future functionalization of biomolecules labeling with fac-[188Re(CO)3(H2O)3]+.