A Validated Chiral LC Method for the Determination of Enantiomeric Purity of Pemetrexed Disodium on an Amylose-Based Chiral Stationary Phase

A simple and new isocratic normal phase chiral HPLC method has been developed for the determination of enantiomeric purity of pemetrexed disodium (l-enantiomer) in bulk drugs with a short run time of about 20 min. Chromatographic separation of l and d-enantiomers of pemetrexed disodium was achieved on an amylose based chiral stationary phase using a mobile phase consists of hexane, ethanol and trifluoro acetic acid. The resolution between the enantiomers was found to be more than 2.0. The system precision and method precision were found to be within 5% RSD for the distomer (d-enantiomer) at its specification level (i.e. not more than 1.0% w/w). The limit of detection and limit of quantification of distomer were 1.6 and 5 μg mL⁻¹, respectively for 10 μL injection volume. The percentage recovery of distomer was ranged from 90.6 to 105.7 in bulk drug samples. The test solution was found to be stable in the diluent for 48 h. The method was found to be specific for the enantiomers of pemetrexed disodium and can be conveniently used for the quantification of undesired d-enantiomer present in the bulk drug samples of pemetrexed disodium.     

Die Kristallstrukturen der Vanadium-Weberite Na2MIIVIIIF7 (MII  Mn,Ni, Cu) und von NaVF4

The Crystal Structures of the Vanadium Weberites Na₂M^IIV^IIIF₇ (M^II ? Mn, Ni, Cu) and of NaVF₄ At single crystals of the vanadium(III) compounds NaVF₄ (a = 790.1, b = 531.7, c = 754.0 pm, β = 101.7°; P2₁/c, Z = 4), Na₂NiVF₇ (a = 726.0, b = 1031.9, c = 744.6 pm; Imma, Z = 4) and Na₂CuVF₇ (a = 717.6, b = 1043.5, c = 754.6 pm; Pmnb, Z = 4) X-ray structure determinations were performed, at Na₂MnVF₇ (a = 746.7, c = 1821.6 pm; P3₂21, Z = 6) a new refinement. NaVF₄ crystallizes in the layer structure type of NaNbO₂F₂. The fluorides Na₂M^IIVF₇ represent new orthorhombic (M^II ? Ni; Cu) resp. trigonal (M^II ? Mn) weberites. The average distances within the [VF₆] octahedra of the four compounds are in good agreement with each other and with data of related fluorides (V? F: 193.3 pm). The differences between mean bond lengths of terminal and bridging F ligands are 5% in NaVF₄, but less than 1% in the weberites. Details and data for comparison are discussed.     

镍(Ⅱ)、镉(Ⅱ)与去甲基斑蝥酸钠和咪唑配合物的结构、与DNA/BSA的作用及抗增殖活性

以2种配体去甲基斑蝥酸钠(Na₂DCA=7-氧杂二环[2.2.1]庚烷-2,3-二甲酸钠)和咪唑(IM),分别与镍(Ⅱ)和镉(Ⅱ)的醋酸盐通过溶液法合成了2种配合物[Ni(IM)(DCA)(H₂O)₂]·2H₂O(1),[Cd₂(IM)₄(DCA)₂]·2H₂O(2)。应用元素分析、热重分析、红外光谱及X-射线单晶衍射法对配合物的组成和结构进行了表征。配合物1与2的中心离子分别与咪唑的亚胺氮原子、去甲基斑蝥酸根的羧基氧原子和醚键氧原子配位,配位数均为6,分别为单核(1)和双核(2)配合物。通过紫外光谱法、荧光光谱法和粘度法研究了配合物与DNA的相互作用。结果表明,配合物能通过部分插入模式与DNA发生较强的结合作用(K_b:5.51×10³(1)、1.01×10³(2)L·mol^-1)。同时,利用荧光光谱法研究了配合物与牛血清白蛋白(BSA)的相互作用。配合物能与BSA发生强烈的相互作用(K_AM:1.91×10⁵(1)和6.17×10⁵(2)L·mol^-1),结合位点数均为1。测试了配合物对人肝癌细胞(SMMC₇₇₂₁)和人乳腺癌(MCF-7)的体外抗增殖活性。结果显示,配合物对不同癌细胞具有选择性抑制作用。镍配合物(1)对SMMC₇₇₂₁的抗癌活性较去甲基斑蝥酸钠有明显提高。     

Diorganotin(IV) Complexes with Monohydrate Disodium Salt of Iminodiacetic Acid: Synthesis,Characterization, Crystal Structure and Biological Activities

Diorganotin(IV) derivatives have been synthesized by the reaction of R₂SnL₂ (R=n‐Bu 1 , Ph 2 ) with monohydrate disodium salt of iminodiacetic acid ( Na₂L ) in 1 : 1 M/L ratio under reflux conditions. The compounds have been characterized by FT‐IR, NMR (¹H and ¹³C) spectoscopy, electron ionization mass spectrometry (EIMS), thermogravimetric analyses (TGA) and single crystal XRD. FTIR data indicates a mono‐dentate binding mode of the carboxylic acid group as well as participation of the amino nitrogen and aqua oxygen in coordination with organotin(IV) moieties. NMR data demonstrates a tetra‐coordinated environment around tin(IV) in solution. Mass spectrometric and thermogravimetric analyses verify the close similarities between the molecular structures of both complexes. The thermal stability of diphenyltin(IV) derivative ( 2 ) was found slightly higher than that of the free ligand ( Na₂L ). Single crystal X‐ray analysis of the complex 1 have shown a hexa‐coordinated geometry around Sn(IV) with trans configuration. There are evidences for the existence of intermolecular hydrogen bonding in the structure of the complexes. The products displayed significant antibacterial and antifungal activities in contrast to the biologically inactive ligand precursor. However, the hemolytic cytoxicity of the complexes was comparatively high than the free ligand.     

New noncellular fluorescence microplate screening assay for scavenging activity against singlet oxygen

In the present study, a new fluorescence microplate screening assay for evaluating scavenging activity against singlet oxygen (¹O₂) was implemented. The chemical generation of ¹O₂ was promoted using the thermodissociable endoperoxide of disodium 3,3′-(1,4-naphthalene)bispropionate (NDPO₂). The detection of ¹O₂ was achieved using dihydrorhodamine 123 (DHR), a nonfluorescent molecule that is oxidizable to the fluorescent form rhodamine 123 (RH). The combined use of a ¹O₂-selective generator and a highly sensitive probe (DHR) was then successfully applied to perform a screening assay of the ¹O₂ scavenging activities of ascorbic acid, penicillamine, cysteine, N-acetylcysteine (NAC), methionine, reduced glutathione (GSH), dihydrolipoic acid, lipoic acid, and sodium azide. All of these antioxidants exhibited concentration-dependent ¹O₂ scavenging capacities. They could be ranked according to observed activity: ascorbic acid> cysteine> penicillamine> dihydrolipoic acid > GSH> NAC> sodium azide> lipoic acid (IC₅₀ values of 3.0 ± 0.2, 8.0 ± 0.7, 10.9 ± 0.8, 25.2 ± 4.5, 57.4 ± 5.9, 138 ± 13, 1124 ± 128, 2775 ± 359 μM, mean±SEM, respectively) > methionine (35% of scavenging effect at 10 mM). In conclusion, the use of NDPO₂ as a selective generator for ¹O₂ and its fluorescence detection by the highly sensitive probe DHR is shown to be a reliable and resourceful analytical alternative means to implement a microplate screening assay for scavenging activity against ¹O₂. Generation and detection of singlet oxygen     

Conductivity of Phosphoric Acid, Sodium, Potassium, and Ammonium Phosphates in Dilute Aqueous Solutions from 278.15 K to 308.15 K

Precise conductivity measurements on aqueous solutions of phosphoric acid, sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, diammonium hydrogen phosphate, sodium phosphate, and potassium phosphate were performed from 5 to 35°C. Data analysis was executed by the use of the Quint–Viallard equation for unsymmetrical electrolytes. Equations are given for the concentration dependence of electrolyte and single-ion conductivities at all temperatures.     

Evaluation of gadoxetate disodium as a contrast agent for mouse liver imaging: comparison with gadobenate dimeglumine

We investigated the characteristics of gadoxetate disodium (Gd-EOB-DTPA) as a contrast agent for magnetic resonance imaging of the mouse liver. Mice were imaged sequentially under isoflurane anesthesia using a T1-weighted, three-dimensional fast low-angle shot (3D FLASH) sequence after an intravenous injection of Gd-EOB-DTPA or gadobenate dimeglumine (Gd-BOPTA), and the time course of the contrast effect was examined. The time course of the contrast effect of Gd-EOB-DTPA was also assessed after intravenous injection under pentobarbital anesthesia and after subcutaneous injection while awake or under isoflurane or pentobarbital anesthesia. Moreover, different doses of Gd-EOB-DTPA or Gd-BOPTA were injected subcutaneously into conscious mice, and the clarity of the liver border was evaluated visually. Intravenous injection under isoflurane anesthesia caused rapid contrast enhancement in the liver with both Gd-EOB-DTPA and Gd-BOPTA, and the contrast effect was 41% stronger with Gd-EOB-DTPA. Subcutaneous injection of Gd-EOB-DTPA caused delayed but favorable contrast enhancement in the liver. Washout of Gd-EOB-DTPA was faster in mice injected while awake than in those injected under anesthesia. After intravenous injection, washout was faster under pentobarbital anesthesia than under isoflurane anesthesia. The peak liver contrast was 11% and 18% stronger under pentobarbital anesthesia than under isoflurane anesthesia, after intravenous and subcutaneous injections, respectively. Subcutaneous injection of Gd-EOB-DTPA or Gd-BOPTA caused dose-dependent contrast effects in the liver. At a given dose, the contrast effect tended to be stronger and liver demarcation tended to be clearer with Gd-EOB-DTPA than with Gd-BOPTA. In conclusion, intravenous or subcutaneous injection of Gd-EOB-DTPA produces a favorable contrast effects in the mouse liver, indicating its potential in investigating mouse models of liver diseases. The contrast effects vary between conscious mice and anesthetized mice and among anesthetic agents used.     

离子色谱法测定氯膦酸二钠及其制剂的含量和有关物质

采用抑制型电导检测-离子色谱法同时测定氯膦酸二钠及其制剂的含量和有关物质.色谱条件为阴离子交换色谱柱(IonPac AS11-HC);检测方式为抑制电导检测;柱温30 ℃;流速1.2 mL/min;以KOH溶液为淋洗液,含量测定采用等度洗脱,有关物质检查采用梯度洗脱.氯膦酸二钠在0.0568～0.1895 g/L范围内线性关系良好(r＝0.9999); 注射液和胶囊的平均回收率分别为100.1%(RSD=0.7%)和98.9%(RSD=0.6%);检出限为0.3 ng.各杂质与主成分色谱峰能完全分离.     

亚硫酸氢钠溶液稳定性的探讨

从溶液的酸度、空气及光照、温度等因素对亚硫酸氢钠溶液的稳定性及滴定反应进行实验探讨,选择三乙醇胺(TEA)、甲醛、二乙胺四乙酸二钠(EDTA-2Na)、盐酸羟胺四种常用的螯合剂或强还原剂进行试验,结果表明EDTA-2Na作为溶液的稳定剂效果最好,其次是甲醛,最后是盐酸羟胺。TEA因为其强碱性会降低溶液的稳定性而不宜作为稳定剂。