水溶液微悬浮聚合法制备酸性药物吲哚美辛分子印迹微球及其色谱表征

以带有羧基的酸性药物吲哚美辛为模板分子、碱性的4-乙烯基吡啶为功能单体,采用水溶液微悬浮聚合法制备了用于色谱分离的微米级分子印迹微球.详细讨论了流动相中缓冲溶液的pH值对吲哚美辛在MIMs柱上的容量因子(k′)、分离因子(α)和印迹因子(β)的影响.通过MIMs柱对吲哚美辛和4-氨基吡啶(4-AP)的保留行为的比较,证明以4-乙烯基吡啶为功能单体制得的MIMs对吲哚美辛的识别作用,主要靠吡啶环上氮原子与吲哚美辛羧基之间的离子键相互作用,以及吡啶环与模板分子之间的π-π相互作用.     

Synthesis,characterization and effects of arm number on properties of amphiphilic polyurethanes as drug delivery carriers

Amphiphilic polyurethanes based on methoxy poly(ethylene glycol) (mPEG) and poly(?-caprolactone) diol (PCL) with different arm numbers such as two, three and four were successfully synthesized. Their structures were confirmed by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (¹H NMR) and gel permeation chromatography (GPC). The effects of arm number on properties of amphiphilic polyurethanes were studied. Pyrene fluorescence probe technique and dynamic light scattering (DLS) analyses showed that the CMC value and the micellar size of the resultant amphiphilic polyurethanes decreased and the micellar stability against dilution enhanced with increasing the arm number of polyurethane. Using indometacin (IMC) as a model drug, the results indicated that the drug loading capacity and in vitro drug sustained release effect of polyurethane with four arms were better than those of polyurethanes with two and three arms.     

Polyelectrolyte titration using fluorescent indicator. I. Direct titration of anionic and cationic polyelectrolytes with 10−4N standard solutions

The polyelectrolyte titration, which was originally called colloid titration, is based on the stoichiometric reaction between positively charged colloidal particles and negatively charged ones. In the conventional method, the metachromatic color change of the indicator, toluidine blue, from blue to red-purple has been applied for the determination of the end point in the titration. 2.5 × 10^?3N potassium polyvinylsulfonate (KPVS) is usually used as the standard titrant. In this work, fluorescent indicators such as 6-(p-toluidino)-2-naphthalene sulfonate (TNS), acridine orange, etc., have been introduced. The fluorescence intensity was measured using the spectrophotometer equipped with magnetic stirrer and connected with a vinyl tube attached to the hand piston burette. For example, TNS is practically nonfluorescent, but it exhibits strong fluorescence when it is bound to a cationic polyelectrolyte (CP). The fluorescence of the TNS–CP complex is diminished by titration with KPVS standard solution since TNS is liberated from the complex by substitution with KPVS. After the equivalent point, the fluorescence intensity becomes constant and the end point can thus be detected by that point. It has been elucidated that the very dilute standard solution like 1 × 10^?4N can be used because the sensitivity of fluorescence detection is extremely high. © 1993 John Wiley & Sons, Inc.     

滴定量热法研究连串一级反应热动力学

本文用滴定量热法分别建立了滴定期和停滴反应期1-1级连串反应热动力学的数学模型。根据这两种模型,由非线性最小二乘法原理直接拟合单次实验结果可同时求得1-1级连串反应的速率常数（ k ₁和 k ₂）和摩尔反应焓。并用滴定量热法研究了丁二酸二乙酯皂化反应的热动力学,实验结果验证了两种数学模型的正确性。     

A carboxyl porphyrin zinc(II)–copper(II) supramolecular system with fluorescence strengthening properties

The supramolecular self-assembly behavior, by hydrogen-bonding, of zinc(II) [Zn(p-CPTPP)], copper(II) [Cu^II-(p-CPTPP)] complexes [(p-CPTPP) = 5-(p-carboxyl)-phenylene-methanamidophenyl-10,15,20-triphenylporphyrin] were studied by fluorescence spectroscopic titration and by u.v.–vis. spectra. The fluorescence strengthening character was observed in the Zn(p-CPTPP)/Cu^II(p-CPTPP) system in a fluorescence spectroscopic titration experiment. The formation constant was determined from the fluorescence spectroscopic titration data and the fluorescence strengthening property of the system was discussed using the fluorescence spectrum of the charge-separated state obtained by the method of spline wavelet least squares.     

高效液相色谱法测定人血清中阿西美辛和吲哚美辛

摘要：建立了测定人血清中阿西美辛及其活性代谢物吲哚美辛的高效液相色谱法。分析柱为Spherisorb-C8（5μm）,4.6mm×250mm,流动相为V（醋酸盐缓冲液,pH4.6）:V（乙腈）:V（甲醇）=55:40:5,流速1.0mL/min,检测波长254nm。血清中药物质量浓度为12.5μg/L～1.6mg/L时,阿西美辛、吲哚美辛峰高与内标甲苯磺丁脲峰高比值和质量浓度呈良好的线性关系;阿西美辛日内、日间变异系数分别为3.6％和5.6％,平均回收率为78.3％;吲哚美辛日内、日间变异系数分别为2.4     

Calibration of titration methods

Summary A calibration method is proposed which makes it possible to use titration techniques in the presence of systematic errors, even if these errors depend on the concentrations of the analytes. The approach uses an empirical calibration model which approximates the relationship between apparent (found) and true concentrations of the analytes. Also a calibration of the physical model of the titration process is proposed, as well as a method of determination of the model parameters, which are useful when analytes are determined by fitting the model to experimental data of titration. Both approaches, empirical and based on the physical model, may be applied jointly. The example presented reveals high efficiency of the proposed approach in cases when a deficient physicochemical model of the titration process is used in the determination of an analyte concentration (simulated titration data applied). The calibration proposed may be considered as a generalization of the titrant standardization used in the conventional volumetric analysis. It may be applied to all titration techniques and for all methods of end-point detection and determination of the concentration of analytes. It opens new possibilities for the development of titration methods. Permanent address: Department of Analytical Chemistry, Jagiellonian University, Karasia 3, PL-30-060 Krakow, Poland     

Oxidability Determination in Waste Waters Using an Automatic Titrator Based on a Multicommutated Unsegmented Flow System

Abstract

The automatic titrator based on a multicommutated unsegmented flow system was applied to redox titrations and used for oxidability determination in waters analysis. This automatic titrator allows the attainment of complete titration curves, being the determination of titrand concentration performed without requiring any prior calibration. After sample treatment (oxidation step), the oxidability determination in waste water samples was accomplished by the automatic flow titrator (titration step). Repeated determinations of standard solutions gave a 3.5% RSD (n=10, 0.010M) for repeatability and a 3.2% RSD (n=2, 0.057M) for reproducibility. Samples results (n=9) were in good agreement (t-test) with those obtained with a reference procedure.     

Investigation on drying conditions and assays of amidosulfuric acid and sodium carbonate by acidimetric coulometric titration and gravimetric titration

Amidosulfuric acid and sodium carbonate as standards for acid–base titrimetry were assayed by coulometric titration and gravimetric titration. Amidosulfuric acid was directly assayed by coulometric titration with electrogenerated hydroxide ions, and sodium carbonate was assayed by gravimetric back-titration. For sodium carbonate, excess amount of sulfuric acid, whose concentration was determined by coulometric titration, was added to sodium carbonate, and then gravimetrically back-titrated using a sodium hydroxide solution whose concentration was determined by gravimetric titration using the sulfuric acid. The accuracy of the coulometric titration for amidosulfuric acid and sulfuric acid was evaluated by examining the current efficiency of pulse electrolysis, the amount of the electrolysis current used, and the time spent for a titration. In addition, the drying conditions for high purity primary standards have a significant effect on the titration results due to changes in the acid–base assay. The suitable drying conditions for amidosulfuric acid and sodium carbonate were evaluated by mass-change measurements, coulometric titration and gravimetric titration. The measurement uncertainties were estimated from the uncertainties on the titration processes. Finally, the assays of amidosulfuric acid and sodium carbonate were 99.986% ± 0.010% (k = 2) after drying at 50 °C for 2 h, and 99.970% ± 0.016% (k = 2) after drying at 280 °C for 4 h, respectively. In addition, the international consistency was confirmed by measuring certified reference materials (CRMs) available from different National Metrology Institutes, and the compatibility of values among CRMs was experimentally ascertained.     

Complexation of Gd<Superscript>III</Superscript> with tetra-<Emphasis Type="Italic">p-tert</Emphasis>-butylthiacalix[4]arenoic acid in micellar media

The conditions for the formation of gadolinium(III) complexes possessing high relaxivity with various tetraacid stereoisomers based on p-tert-butylthiacalix[4]arene in micellar solutions of nonionic surfactants were established. The acid-base properties of individual isomers of the ligand were studied by pH-metric titration and UV spectroscopy. The composition and stability constants of the solubilized gadolinium(III) complexes with the obtained thiacalixarenes were determined using computer simulation of the NMR relaxation data.     

Quantitative determination of acemetacin and its metabolite indometacin in blood and plasma by column liquid chromatography

A column liquid chromatographic (LC) method using UV detection for the determination of acemetacin and its metabolite indometacin in blood is described. The lower detection limit for both compounds is ca. 25 micrograms/l, the precision (coefficient of variation) is 6% for acemetacin and 10% for indometacin. The method is also suited for determination of both compounds in plasma, precisions in this case are even better than for blood, i.e. around 3% for both acemetacin and indometacin. Blood samples of three volunteers who had received 90 mg of acemetacin orally were analysed using the new method and very good agreement with results from a thin-layer chromatographic/fluorescence method was found.     

Basicity of Secondary Penta-2,4-diynylamines and Their Reactions with Phenyl Isothiocyanate

Secondary penta-2,4-diynylamines were synthesized, and their pK _a(MeOH) values were obtained by means of nonaqueous potentiometric titration. The reactions of the amines with phenyl isothiocyanate, leading to 2-(phenylimino)-5-(prop-2-ynilidene)thiazolidines, were studied. The N-butyl- and N-benzylthiazolidines with alkyl substituents at the triple bond, formed by the reactions, undergo autooxidation into thiazolidin-4-ones.     

Pyridyl-substituted porphyrins: I. Synthesis and basicity of monopyridylporphyrins

13,17-Diethyl-2,3,7,8,12,18-hexamethyl-5-(pyridin-2-yl)porphyrin, 13,17-diethyl-2,3,7,8,12,18-hexamethyl-5-(pyridin-2-yl)porphyrin, and 13, 17-diethyl-2,3,7,8,12,18-hexamethyl-5-(pyridin-4-yl)porphyrin were synthesized, and their basic properties were studied by spectrophotometric titration in the system ethanol-sulfuric acid. Concentration ranges for the existence of mono- and dicationic forms of meso-pyridyl-substituted porphyrins and the corresponding ionization constants were determined.     

Alternating copolymer of butadiene and propylene. IV. Studies on the catalysts for alternating copolymerization

The catalysts for alternating copolymerization of butadiene and propylene were investigated by means of ESR technique and potentiometric titration. It was found that several kinds of active species for the production of alternating copolymer, 1,2-polybutadiene, and trans-1,4-polybutadiene are formed, depending upon the catalyst composition of VO(acac)₂? Et₃Al? Et₂AlCl. ESR and potential titration studies suggest that the active species for alternating copolymerization is a divalent vanadium compound existing in an associated form.     

Non-aqueous and two-phase titrimetric assay of isoxsuprine hydrochloride in pharmaceuticals

Based on the nitrogenous base or quaternary ammonium moiety in isoxsuprine hydrochloride (ISX), two highly accurate and selective titrimetric methods are proposed f or the determination of ISX in spiked human urine, injection and tablets. Non-aqueous titration (Method A) involves removal of protonated amine using mercuric acetate for enhanced basic nitrogen prior to titration with perchloric acid in an acetic acid medium using crystal violet as indicator. Two-phase titration (Method B) is based on ion association complex formation between sodium lauryl sulphate (SLS) and protonated amine of ISX at pH 2.5 in aqueous phase, end point being detected by change in dimethyl yellow color in chloroform layer. The methods are applicable over the concentration range 2.0–20.0 mg and 1.0–10.0 mg for method A and method B, respectively. Calculations are based on 1: 1 molar ratio, i.e., JSX: HClO₄ for method A and ISX: SLS for method B, owing to the presence of one nitrogen atom. Method A is applicable to the determination of ISX in tablets whereas method B is applicable to spiked human urine, injection and tablets. The methods are validated statistically by comparing the results with those of the reference method by applying the Student’s t-test and F-test. The accuracy was further ascertained by recovery studies via standard addition technique.     

Conformation and Atropisomeric Properties of Indometacin Derivatives

The stereochemistry around the N‐benzoylated indole moiety of indometacin was studied by restricting the rotation about the N? C7′ and/or C7′? C1′ bond. In the 2′,6′‐disubstituted ones, an atropisomeric property was found and the atropoisomers were separated and isolated as stable forms. Their biological abilities to inhibit cyclooxygenase‐1 (COX‐1) and cyclooxygenase‐2 (COX‐2) were examined. Only the aR‐isomer showed specific inhibition of COX‐1, and COX‐2 was not inhibited by either atropisomer. Conformational analysis in NMR studies and X‐ray crystallography, and CD spectra in combination with calculations were utilized to elucidate the bioactive conformations.     

Complexes of Co(II), Ni(II), Cu(II), and Pd(II) with Sulfametrole-Cyclodiphosph(V)azane Derivatives

Novel [1,3-di-[N ₁ -4-methoxy-1,2,5-thiadiazole-3-yl-sulfanilamide(sulfametrole)]-2″4-bis-[1,3-dithiole-2-thione-4,5-dithiolate]-2′,4′-dichl-orocyclodiphosph(V)azane] (III) , was prepared and their coordinating behavior towards the metal ions Co(II), Ni(II), Cu(II), and Pd(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV, ¹ H, and ³¹ P NMR, ESR, magnetic susceptibility, molar ratio, conductometric titration and electrical conductivity measurements. The prepared complexes showed high to moderate bactericidal activity compared with the ligand.     

A novel pyrene-based “off–on” fluorescent probe with high selectivity and sensitivity for Hg2+

In this article, a novel “off–on” fluorescent probe 2-(pyren-1-ylmethylene)-1H-indene-1,3(2H)-dione ( PID ) for Hg²⁺ was designed and synthesized. The selectivity, concentration titration, pH titration, time dependence, limit of detection, and recognition mechanism of PID for Hg²⁺ in CH₃CH₂OH/H₂O solution were also investigated. The results indicated that PID exhibited high selectivity, sensitivity, and fast response to Hg²⁺, and the limit of detection was as low as 20.7 nmol/L. In addition, PID could work in a wide pH range, and the determination of Hg²⁺ in water samples showed that it could be used as a potential detection tool in practical application.     

Synthesis of a fluorescein–porphyrin hybrid and its supramolecular self-assembly with amino-porphyrinatocopper(II) by hydrogen bonding

A fluorescein–porphyrin hybrid (Fl-PTPP) has been synthesized and characterized by UV/Vis, IR, ¹H NMR, ES-MS and elemental analysis. The supramolecular self-assembly of Fl-PTPP with the copper(II) complex of 5-(p-amino-phenyl)-10,15,20-triphenylporphyrin, (CuAPTPP), by hydoxyl-amino type hydrogen bonding was studied using vapor pressure osmometry (VPO) measurements, ES-MS, UV/Vis, ¹H NMR and fluorescence spectroscopic titration. The data indicate formation of a (Fl-PTPP)–CuAPTPP supramolecular complex. Fluorescence strengthening character was observed in a spectroscopic titration experiment for the Fl-PTPP/CuAPTPP system. The association constant of the supramolecular complex was calculated from the fluorescence titration data, and found to be less than that of a carboxyl–carboxyl type hydrogen-bonding system.     

Facile synthesis of an optical sensor for CO32− and HCO3− detection

A novel fluorogenic signalling probe (E)-3-(4-methoxyphenyl)-4-[(4-nitrobenzylidene)amino]-1H-1,2,4-triazole-5(4H)-thione (6) for the carbonate and bicarbonate ions has been developed through microwave assisted Schiff base formation reaction. The anion recognition occurs through hydrogen bonding assessed by ¹H NMR titration experiments. The photophysical results of probe 6 corroborates its applicability as an optical sensing platform for carbonate as well as bicarbonate ions in mixed aqueous organic media depending on pH of reaction solution. The fluorescence emission signal enhancement at 424 nm and considerable shift in the signal position as well as molar absorptivity to the probe absorption bands upon CO₃^2? and HCO₃^? addition suggest the affinity of probe 6 towards these ions in comparison to a variety of competitive ions in aqueous/ethanol (7:3, v/v) at neutral pH and ambient temperature. From the fluorescence titration experiment, the limit of detection was calculated to be 1.91 μM.