HPLC同时测定金胆片中的龙胆苦苷和白藜芦醇及其苷的含量

建立了同时测定金胆片中龙胆苦苷、白藜芦醇及其苷含量的HPLC方法,以求用于中成药的质量监测.采用梯度洗脱,色谱柱为μBondapakTMC18(3.9 mm×300 mm,10μm)柱,流动相为水一甲醇,流速为1.0 mL·min-1,检测波长为288 mm,0.02 AUFS,样品采用乙醇-水(85:15,v/v)超声提取.龙胆苦苷线性范围1.877-75.06 mg·L-1.r=0.999 9;白藜芦醇苷的线性范围6.432-257.28mg·L-1,r=0.999 9;白藜芦醇的线性范围0.680-27.19 mg·L-1,r=0.999 9;平均加标回收率分别为:100.78%,RSD=3.61%;104.67%,RSD=3.29%;101.48%,RSD=3.68%;本方法灵敏度高、选择性好、操作简便、费用低,适合于该类中成药的有效成分快速分离分析.     

Recent studies on selected botanical dietary supplement ingredients

The market for botanical dietary supplements in the US has grown rapidly during the last 15 years. Use of newly introduced botanical ingredients has often outpaced an adequate scientific understanding of the ingredients themselves. This may lead to problems, including misidentification, mislabeling, adulteration, and toxicity related to the intended ingredient or one substituted for it. This article reviews recent work with several botanical ingredients (Ephedra, Citrus species, Hoodia gordonii, Teucrium, isoflavones) that illustrates the complexity of the current situation and approaches that contribute to ensuring the quality of botanical ingredients. Recent work with contamination of botanical products by mycotoxins is also reviewed. The need for tools for botanical authentication and methods for reproducible extraction of bioactive constituents is critical. Such tools, and improved analytical techniques for identifying potentially bioactive constituents in fresh plant material and in concentrated extracts and for detection of hazardous contaminants, are expected to improve the overall quality and safety of botanical dietary supplement ingredients.     

Tumbling dynamics of individual absorbed polymer chains in shear flow

The tumbling dynamics of individual absorbed polymer chains in shear flow is studied by employing multi-particle collision dynamics simulation techniques combined with molecular dynamics simulations.We find that the dependence of tumbling frequencies on shear rate is independent of both adsorption strength and surface corrugate.     

Eight salt forms of sulfadiazine

Proton transfer to the sulfa drug sulfadiazine [systematic name: 4‐amino‐N‐(pyrimidin‐2‐yl)benzenesulfonamide] gave eight salt forms. These are the monohydrate and methanol hemisolvate forms of the chloride (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium chloride monohydrate, C₁₀H₁₁N₄O₂S⁺·Cl⁻·H₂O, (I), and 2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium chloride methanol hemisolvate, C₁₀H₁₁N₄O₂S⁺·Cl⁻·0.5CH₃OH, (II)); a bromide monohydrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium bromide monohydrate, C₁₀H₁₁N₄O₂S⁺·Br⁻·H₂O, (III)), which has a disordered water channel; a species containing the unusual tetraiodide dianion [bis(2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium) tetraiodide, 2C₁₀H₁₁N₄O₂S⁺·I₄²⁻, (IV)], where the [I₄]²⁻ ion is located at a crystallographic inversion centre; a tetrafluoroborate monohydrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium tetrafluoroborate monohydrate, C₁₀H₁₁N₄O₂S⁺·BF₄⁻·H₂O, (V)); a nitrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium nitrate, C₁₀H₁₁N₄O₂S⁺·NO₃⁻, (VI)); an ethanesulfonate {4‐[(pyrimidin‐2‐yl)sulfamoyl]anilinium ethanesulfonate, C₁₀H₁₁N₄O₂S⁺·C₂H₅SO₃⁻, (VII)}; and a dihydrate of the 4‐hydroxybenzenesulfonate {4‐[(pyrimidin‐2‐yl)sulfamoyl]anilinium 4‐hydroxybenzenesulfonate dihydrate, C₁₀H₁₁N₄O₂S⁺·HOC₆H₄SO₃⁻·2H₂O, (VIII)}. All these structures feature alternate layers of cations and of anions where any solvent is associated with the anion layers. The two sulfonate salts are protonated at the aniline N atom and the amide N atom of sulfadiazine, a tautomeric form of the sulfadiazine cation that has not been crystallographically described before. All the other salt forms are instead protonated at the aniline group and on one N atom of the pyrimidine ring. Whilst all eight species are based upon hydrogen‐bonded centrosymetric dimers with graph set R₂²(8), the two sulfonate structures also differ in that these dimers do not link into one‐dimensional chains of cations through NH₃‐to‐SO₂ hydrogen‐bonding interactions, whilst the other six species do. The chloride methanol hemisolvate and the tetraiodide are isostructural and a packing analysis of the cation positions shows that the chloride monohydrate structure is also closely related to these.     

Hirshfeld surface analysis of sulfameter (polymorph III), sulfameter dioxane monosolvate and sulfameter tetrahydrofuran monosolvate,all at 296 K

The ability of the antibacterial agent sulfameter (SMT) to form solvates is investigated. The X‐ray crystal structures of sulfameter solvates have been determined to be conformational polymorphs. Both 1,4‐dioxane and tetrahydrofuran form solvates with sulfameter in a 1:1 molar ratio. 4‐Amino‐N‐(5‐methoxypyrimidin‐2‐yl)benzenesulfonamide (polymorph III), C₁₁H₁₂N₄O₃S, (1), has two molecules of sulfameter in the asymmetric unit cell. 4‐Amino‐N‐(5‐methoxypyrimidin‐2‐yl)benzenesulfonamide 1,4‐dioxane monosolvate, C₁₁H₁₂N₄O₃S·C₄H₈O₂, (2), and 4‐amino‐N‐(5‐methoxypyrimidin‐2‐yl)benzenesulfonamide tetrahydrofuran monosolvate, C₁₁H₁₂N₄O₃S·C₄H₈O, (3), crystallize in the imide form. Hirshfeld surface analyses and fingerprint analyses were performed to study the nature of the interactions and their quantitative contributions towards the crystal packing. Finally, Hirshfeld surfaces, fingerprint plots and structural overlays were employed for a comparison of the two independent molecules in the asymmetric unit of (1), and also for a comparison of (2) and (3) in the monoclinic crystal system. A three‐dimensional hydrogen‐bonding network exists in all three structures, involving one of the sulfone O atoms and the aniline N atom. All three structures are stabilized by strong intermolecular N—H...N interactions. The tetrahydrofuran solvent molecule also takes part in forming significant intermolecular C—H...O interactions in the crystal structure of (3), contributing to the stability of the crystal packing.     

Chemical Assembly Systems: Layered Control for Divergent,Continuous, Multistep Syntheses of Active Pharmaceutical Ingredients

While continuous chemical processes have attracted both academic and industrial interest, virtually all active pharmaceutical ingredients (APIs) are still produced by using multiple distinct batch processes. To date, methods for the divergent multistep continuous production of customizable small molecules are not available. A chemical assembly system was developed, in which flow‐reaction modules are linked together in an interchangeable fashion to give access to a wide breadth of chemical space. Control at three different levels—choice of starting material, reagent, or order of reaction modules—enables the synthesis of five APIs that represent three different structural classes (γ‐amino acids, γ‐lactams, β‐amino acids), including the blockbuster drugs Lyrica and Gabapentin, in good overall yields (49–75 %).     

重频XeF(C-A)蓝绿激光器中XeF2浓度的监测与控制

 介绍了采用光谱吸收法实时监测重复频率XeF(C-A)蓝绿激光器中XeF₂气体浓度的原理和控制XeF₂气体浓度的方法；给出了监测窗中XeF₂气体浓度与激光器气室中的XeF₂气体浓度之间的关系，获得了在不同主/载气路气流量条件下激光器气室中XeF2气体浓度值，通过调节主/载气路的气流量实现了对激光器腔室内XeF₂气体浓度的控制，保证了XeF(C-A)蓝绿激光器1 Hz重频运行。     

Solid‐State NMR Studies of Pharmaceutical Systems

Abstract

High‐and low‐resolution solid‐state nuclear magnetic resonance (SSNMR) applications to the study of pharmaceuticals are reviewed. Examples are shown involving the use of mono‐and bidimensional SSNMR techniques based on different nuclear interactions and the measurement of several nuclear parameters, such as chemical shifts, line widths, and relaxation times (T₁, T₂, T_1ρ). The systems investigated include pure active pharmaceutical ingredients (APIs), substances used as drug excipients, and solid dispersions formed by APIs and excipients, up to final drug formulations. The most important aspects treated concern structural, dynamic, and morphological properties, and, in particular, identification, characterization, and quantitation of polymorphs and related forms, conformational and crystalline packing behavior, amorphous phase properties and stability, effects of drug processing, molecular motions, API‐excipient and excipient‐excipient chemical and physical interactions, and phase mixing in heterophasic systems.     

用NMR测定辐射剂量

本文介绍了利用琼酯糖-亚铁为剂量液,经辐照,产生糖的自由基、质子和三价铁离子。根据Fe~(3+)本身具有的弛豫能力-减小弛豫时间,利用NMR法测量出不同剂量下的T_1值并获得整个辐照过程弛豫速率随剂量分布的曲线。还观察到整个辐射过程体系氧化还原反应的动态变化过程。