桂枝的引药作用机制及其对环丙沙星在小鼠体内分布的影响

研究了桂枝和桂皮醛对环丙沙星在小鼠体内分布的影响,并基于此探讨了桂枝作为引药使用的作用机制.实验中将小鼠分为三组,分别灌胃生理盐水、桂枝(50gkg-1)和桂皮醛(0.25mLkg-1),然后对三组小鼠尾静脉注射环丙沙星(20mgkg-1),并以荧光法测定不同时间点小鼠体内各组织中环丙沙星的浓度.结果显示桂枝、桂皮醛均促进了环丙沙星在四肢的分布,桂枝与桂皮醛组相对于生理盐水组可将环丙沙星在四肢的含量提高约40%~200%,证实了桂枝引药到达肢节的作用.桂枝与桂皮醛组对环丙沙星分布情况的影响没有显著性差异,说明桂皮醛很可能是发挥桂枝引药作用的主要物质.     

Block copolymer micelles with enzyme molecules at the interfaces

This research provides an efficient method for the fabrication of hybrid micelles with enzyme molecules at the interfaces. Amphiphilic block copolymer is synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization, and thiol‐modified porcine pancreatic lipase (PPL‐SH) is obtained by treatment of native PPL with Traut's reagent. PPL‐SH is conjugated to the block copolymer chains by thiol‐disulfide exchange reaction. In phosphate buffered saline, the bioconjugate self‐assembles into micelles with enzyme molecules at the interfaces between hydrophobic cores and hydrophilic coronae. The bioactivity of the enzyme molecules on the micelles are compared with the native enzyme. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2047–2052     

Palladium(II) complexes of Y,C,Y‐chelated phosphines: synthesis,structure, and catalytic activity in Suzuki–Miyaura reaction

The phosphines L¹PPh₂ (1) and L²PPh₂ (2) containing different Y,C,Y‐chelating ligands, L¹ = 2,6‐(^tBuOCH₂)₂C₆H₃^? and L² = 2,6‐(Me₂NCH₂)₂C₆H₃^?, were treated with PdCl₂ and di‐µ‐chloro‐bis[2‐[(N,N‐dimethylamino)methyl]phenyl‐C,N]‐dipalladium(II) and yielded complexes trans‐{[2,6‐(^tBuOCH₂)₂C₆H₃]PPh₂}₂PdCl₂ (3), {[2,6‐(Me₂NCH₂)₂C₆H₃]PPh₂} PdCl₂ (4), {[2,6‐(^tBuOCH₂)₂C₆H₃]PPh₂}Pd(Cl)[2‐(Me₂NCH₂)C₆H₄] (5) and {[2,6‐(Me₂NCH₂)₂C₆H₃]PPh₂}Pd(Cl)[2‐(Me₂NCH₂)C₆H₄] (6) as the result of different ability of starting phosphines 1 and 2 to complex PdCl₂. Compounds 3–6 were characterized by ¹H, ¹³C, ³¹P NMR spectroscopy and ESI‐MS. The molecular structures of 3,4 and 6 were also determined by X‐ray diffraction analysis. The catalytic activity of complexes 3–6 was evaluated in the Suzuki‐Miyaura cross‐coupling reaction. Copyright © 2010 John Wiley & Sons, Ltd.     

Simultaneous Separation and Determination of Isosorbide Dinitrate and Isosorbide 5-Mononitrate in Human Plasma by LC–MS–MS

A sensitive, selective, and simple liquid chromatography-tandem mass spectrometry method has been developed for the simultaneous separation and determination of isosorbide dinitrate and its active metabolite, isosorbide 5-mononitrate, in human plasma. Topiramate was used as the internal standard. Sample preparation consisted of a simple one-step liquid–liquid extraction with ethylacetate without pH adjustment. The method was fully validated with respect to linearity, sensitivity, specificity, recovery, accuracy, and precision. Isosorbide dinitrate and isosorbide 5-mononitrate were stable in standard solution and in plasma samples under storage and processing conditions. The assay was successfully applied to the pharmacokinetic study of isosorbide dinitrate and isosorbide 5-mononitrate in human plasma.     

Hydroformylation of Oct‐1‐ene in Novel Ionic Liquid Crystals

Hydroformylation of oct‐1‐ene leading to nonanal (denoted by n) and 2‐methyloctanal (denoted by iso), in a novel series of caprolactam‐based and common imidazolium‐based ionic liquid crystals (ILCs; see Fig. 1) carried out for the first time (caprolactam=hexahydro‐2H‐azepin‐2‐one) (Scheme). Variation of the chain length (n) of the alkyl substituent (C_n) at the caprolactam cation (CP⁺) from n=12 to 18 caused the n/iso ratios to vary from 1.7 to 2.9. Meanwhile, the TOF (turnover frequency) decreased from 148 to 122 mol mol⁻¹ h⁻¹. Hydroformylation in the imidazolium‐based ILCs revealed that [C₁₆MIm]⋅BF₄ (n/iso 5.2, TOF 969 mol mol⁻¹ h⁻¹) was more favorable than [C₁₆MIm]⋅MsO (n/iso 3.7, TOF 969 mol mol⁻¹ h⁻¹) for the formation of the unbranched aldehyde. Although the n/iso ratio in caprolactam‐based ILCs was lower than that in imidazolium‐based ILCs, the conversions are higher in the former ILCs on the whole. It should be noted that the lamellar mesophase has a strong effect on the regioselectivity and TOF of the hydroformylation. Also, it is evident that the influences of different ILCs on the hydroformylation under the various reaction conditions are greatly different. The identification of the reaction products was established by GC and GC/MS analyses.     

Preparation of hierarchical polyaniline nanotubes based on self‐assembly and its electrochemical capacitance

This article reports the preparation and self‐assembly of polyaniline (PANI) nanotubes, which were chemically synthesized by using in situ doping polymerization in the presence of ammonium persulfate (APS; (NH₄)S₂O₈) as the oxidant without the use of an external template. The synthesized hierarchically nanotubes with a shape of a single nanotube with a length of 0.6 to 0.8 µm and an average with of 100 nm assembled from nanoparticles. The effects of the [salicylic acid]/[aniline] ratio on the size and capacitance of PANI nanotubes were studied. The specific capacitance behavior of the PANI nanotubes was also investigated by using cyclic voltammogram and galvanostatic charge–discharge tests. A maximum discharge‐specific capacitance of 422.5 F/g could be achieved, suggesting its potential application in electrode material for electrochemical capacitors. Copyright © 2011 John Wiley & Sons, Ltd.