光谱法研究奥沙利铂与牛血清白蛋白的相互作用

在模拟人体生理条件下,运用荧光光谱法和同步荧光光谱法研究奥沙利铂铂与牛血清白蛋白(BSA)的相互作用。实验结果表明:奥沙利铂与BSA形成1∶1的复合物引起BSA的荧光猝灭,其猝灭类型为静态猝灭。奥沙利铂与BSA结合常数为2.67×104L·mol~(-1),两者以氢键和范德华力为主。同步荧光光谱表明两者相互作用使色氨酸残基所处的微环境发生改变。     

光谱法研究呋苄西林钠与牛血清白蛋白的作用

采用紫外、荧光、红外光谱法研究了磷酸缓冲液中呋苄西林钠(FBS)与牛血清蛋白(BSA)的相互作用。结果表明,FBS与BSA有较强的相互作用,FBS对BSA内源荧光有猝灭作用,静态猝灭是引起BSA荧光猝灭的主要原因。按照Stern-Volmer方程和双对数方程分析处理实验数据,得到了不同温度下FBS与BSA反应的结合常数和结合位点数,常温(26℃)下,分别为1.04×105和1.09;实验结果还表明,FBS与BSA之间的相互作用影响了BSA的二级结构,使其构象发生变化。     

荧光光谱法研究辛硫磷与牛血清白蛋白的相互作用

用荧光光谱法研究了在生理pH条件下杀虫剂辛硫磷与牛血清白蛋白(BSA)的相互作用. 结果表明: 辛硫磷对BSA的荧光有较强的猝灭作用, 该猝灭属于静态猝灭. 根据猝灭结果求得了不同温度下辛硫磷与牛血清白蛋白结合作用的结合位点数、结合常数及反应热力学参数, 并据此确定它们之间主要的相互作用力为疏水作用力. 用同步荧光光谱法探讨了辛硫磷对BSA构象的影响.     

芥子碱与牛血清白蛋白的相互作用

利用荧光光谱法研究了新芥子碱与牛血清白蛋白(BSA)的相互作用,结果表明,新芥子碱对牛血清白蛋白的荧光有猝灭作用,且荧光光谱有较大的红移,其猝灭类型属于静态猝灭;根据Stern-Volmer荧光猝灭方程计算得到不同温度下的新芥子碱和BSA的结合常数和结合位点数;由实验计算得到该猝灭反应的热力学参数,表明新芥子碱与BSA之间相互作用以氢键和范德华力为主;根据能量转移理论求得新芥子碱与BSA的结合距离及能量转移率。     

荧光光谱法研究注射用头孢美唑钠与牛血清白蛋白的相互作用

运用荧光光谱法研究了注射用头孢美唑钠(Cefmetazole Sodium,CS)与牛血清白蛋白(BSA)的相互作用.CS对BSA具有荧光猝灭作用,其猝灭方式为静态猝灭,求出了猝灭常数,结合常数及结合位点数.在297 K和311 K时用Stern-Volmer方程和热力学方程处理实验数据,得到了结合常数KA、热力学参数...     

荧光法研究金属离子对橙皮素与牛血清白蛋白相互作用的影响

采用荧光光谱和三维荧光光谱法研究了橙皮素(HSP)与牛血清白蛋白(BSA)之间的相互作用,并考察了共存金属离子Cu2+,Zn2+对二者相互作用的影响。实验结果表明,HSP对BSA的内源性荧光具有猝灭作用,猝灭类型为静态猝灭,作用力类型是氢键和范德华力,Cu2+,Zn2+的加入未改变HSP对BSA的猝灭类型和作用力类型。通过比较猝灭常数、结合常数、结合位点数、猝灭效率和三维荧光光谱图变化,推知Cu2+,Zn2+能与BSA产生结合作用,使其成为受制状态下的刚性肽链,从而影响HSP进入BSA疏水腔,减弱了HSP与BSA的结合能力,表现为与HSP存在竞争作用。     

邻苯二甲酸二环己酯与牛血清白蛋白相互作用研究北大核心CSCD

本文利用光谱法和分子对接技术,研究邻苯二甲酸二环己酯(DCHP)与牛血清白蛋白(BSA)的相互作用机制。荧光光谱结果表明,DCHP可以诱导BSA的内源性荧光猝灭,且猝灭机制为静态猝灭;随着DCHP浓度增大,BSA最大发射波长发生蓝移。不同温度下的热力学常数表明,DCHP主要靠氢键和范德华力与BSA相结合;同时DCHP与BSA只有1个结合位点。位点实验结果显示DCHP与BSA在位点Ⅰ结合。同步荧光光谱、三维荧光和圆二色谱结果进一步证实DCHP改变了BSA的构象。通过分子对接技术模拟DCHP与BSA在分子水平上的相互作用机制,结果与光谱学研究结果一致。     

光谱法研究牡荆素与蛋白质相互作用及共存金属离子的影响

利用荧光光谱法和紫外-可见光谱法研究了牡荆素(VT)与牛血清白蛋白(BSA)之间的相互作用.VT对BSA的荧光猝灭为动态猝灭过程,测定了不同温度下的猝灭常数;根据F(o)rster非辐射能量转移理论,计算出VT在BSA中的结合位置与色氨酸残基间的距离为2.675.nm;通过热力学参数推断出VT与BSA之间主要靠疏水作用...     

荧光光谱法研究氨曲南与牛血清白蛋白的相互作用

应用荧光光谱法及紫外可见光谱的方法研究了氨曲南与牛血清白蛋白(BSA)的相互作用.实验结果表明,氨曲南能强烈猝灭牛血清白蛋白的荧光强度,其荧光猝灭机理为动态猝灭.在此基础上计算了二者相互作用的结合常数、结合位点数及△H、△G、△S等热力学参数等.结果表明氨曲南与BSA以1:1结合,其反应为熵驱动,相互作用力主要为疏水力...     

几种金属离子对胭脂红与牛血清白蛋白相互作用的影响——荧光光谱研究

利用荧光光谱法研究了不同温度(15、27、39℃)下食用合成色素胭脂红对牛血清白蛋白(BSA)的内源荧光猝灭特性,考察了Cu2+、Ni 2+、Pb2+等金属离子对二者相互作用的影响,并测定了不同温度下的猝灭常数KSV、结合常数KA和结合位点数n.结果表明,3种金属离子基本不影响胭脂红对BSA荧光猝灭机理,但Cu2+、Ni 2+、Pb2+离子都与BSA有一定的结合能力,可在不同程度上增强胭脂红与BSA的结合作用及其对BSA内源荧光的猝灭.     

Enrofloxacin inclusion complexes with cyclodextrins

Inclusion complexes using α-, β-, γ-, and hydroxypropyl-β-CD (HP-β-CD) were produced with the antibiotic enrofloxacin, with the aim of increasing its solubility by complexation. Phase solubility diagrams were obtained, to confirm the formation of inclusion complexes, and to determine the solubility enhancement and stability constant of each complex. Enrofloxacin inclusion in β-CD showed the highest value of the complex stability constant (35.56?mmol?L^?1), but the greatest increase in solubility was obtained using HP-β-CD reaching a 1258% increase over enrofloxacin solubility in the absence of CD. The order of highest enrofloxacin solubility achieved was: HP-β-CD?>?α-CD?>?γ-CD?>?β-CD. In addition, formation of complexes was confirmed by differential scanning calorimetry and thermogravimetry, applied to the complexes obtained by the kneading technique. The influence of citric acid, alone or as an adjunct of β-CD, on the solubility of enrofloxacin was also determined. A solution of 15?mmol?L^?1 citric acid dissolved 10?g?L^?1 of enrofloxacin, but a gradual increase in β-CD concentration in the presence of citric acid did not increase the degree of solubilization of enrofloxacin.     

恩诺沙星与牛血清白蛋白的相互作用

恩诺沙星与牛血清白蛋白的相互作用;恩诺沙星;牛血清白蛋白;荧光猝灭     

Malonylchitosan Microspheres as a Matrix for Oral Enrofloxacin Delivery

Summary: The purpose of this study was to produce malonylchitosan microspheres to be used as a pH sensitive matrix for the controlled delivery of drugs. Chitosan microspheres were obtained by the coacervation–phase separation method. The microspheres were then treated with malonic acid to obtain amidified chitosan microspheres. The resulting malonylchitosan microspheres were characterized by means of elemental analysis (CHN), infrared spectroscopy, conductometric titration and scanning electron microscopy (SEM). The data obtained from infrared spectroscopy, elemental analysis and conductometric titration of amino groups were consistent with the N-substitution of malonyl groups in the chitosan microspheres. In vivo studies for controlled delivery of enrofloxacin were performed in male Wistar rats and the results indicated increase and prolonged blood levels with delayed peak and improved bioavailability for malonylchitosan microspheres compared to commercial tablets.     

Electroanalytical Determination of Enrofloxacin in Reversed Phase HPLC

The electrochemical behavior of a glassy carbon electrode is investigated towards the oxidation of enrofloxacin in aqueous solutions of different pH. Two oxidative waves are observed at a potential range from 0.70 V to 1.20 V (vs. SCE), the intensity of each depending on the pH of the solution. These results are used to set the parameters for the amperometric detection of enrofloxacin in HPLC analysis. A wide linear range and high sensitivity are obtained for a calibration plot using the optimized experimental conditions. The limit of detection (S/N=3) obtained using those conditions is approximately 0.2 pmol. The applicability of the methodology is demonstrated in the analysis of enrofloxacin in fortified milk samples.     

胶束增敏荧光光谱法测定恩诺沙星的含量

研究了恩诺沙星(EFLX)在胶束体系中的荧光特性,发现十二烷基硫酸钠(SDS)对EFLX有较强的增敏作用,据此建立了胶束增敏荧光光谱法测定恩诺沙星的新方法。方法的线性范围为0-0.64μg/mL,检出限为4.75 ng/mL。     

Determination of the Antibacterial Drug Enrofloxacin by Solid-Phase Spectrofluorimetry

A method for the determination of trace amounts of enrofloxacin based on solid-phase spectrofluorimetry has been developed. The relative fluorescence intensity of enrofloxacin fixed on Sephadex SP C-25 gel was measured directly after packing the gel beads in a 1-mm silica cell, using a solid-phase attachment. The wavelengths of excitation and emission were 277 and 448nm, respectively. The linear concentration range of application was 0.2–4.0ngmL^–1 of enrofloxacin, with a relative standard deviation of 1.2% (for a level of 2.0ngmL^–1) and a detection limit of 0.04ngmL^–1. The method was applied to the determination of enrofloxacin in commercial pharmaceutical formulations and spiked canine serum samples. It was validated using HPLC as a reference method and applying the standard addition methodology. Recovery levels of the method reached 100% in all cases.     

恩诺沙星分子印迹纳米纤维膜的制备及性能

通过沉淀聚合法制备了恩诺沙星（ENRO）分子印迹聚合物（MIPs）微球,将其添加到聚乙烯醇（PVA）溶液中,采用静电纺丝技术制备了恩诺沙星分子印迹纳米纤维膜（MINFMs）. 利用扫描电子显微镜（SEM）研究了纺丝液浓度、纺丝电压及接收距离对MINFMs纤维直径及表面形貌的影响,从溶胀性、孔隙率、吸附容量及吸附选择性等几个方面对印迹膜的性能进行了评价. 结果表明,在环境温度25 ℃、相对湿度 40%~50%、MIPs加入量8%（质量分数）、PVA质量分数7%、纺丝电压15 kV和接收距离25 cm的条件下,得到的MINFMs的纤维形态良好,纤维平均直径为180 nm. MINFMs的溶胀度和孔隙率分别为136.76%和33.42%,均大于非印迹纳米纤维膜（NINFMs）. 动力学吸附性能结果显示,MINFMs在300 min后吸附基本达到平衡,且明显高于NINFMs的吸附量;Scatchard分析结果表明,在所研究的浓度范围内MINFMs对模板ENRO的结合位点是等价的,其离解平衡常数（K_d）与最大表观结合量（Q_max）分别为505.817 mg/L和3.862 mg/g. 与环丙沙星（CIP）和氧氟沙星（OFL）相比,MINFMs对ENRO表现出更强的特异性吸附能力.     

Molecularly-Imprinted Materials for Potentiometric Transduction: Application to the Antibiotic Enrofloxacin

Enrofloxacin (ENR) is an antimicrobial used both in humans and in food producing species. Its control is required in farmed species and their surroundings in order to reduce the prevalence of antibiotic resistant bacteria. Thus, a new biomimetic sensor enrofloxacin is presented. An artificial host was imprinted in specific polymers. These were dispersed in 2-nitrophenyloctyl ether and entrapped in a poly(vinyl chloride) matrix. The potentiometric sensors exhibited a near-Nernstian response. Slopes expressing mV/Δlog([ENR]/M) varied within 48–63. The detection limits ranged from 0.28 to 1.01 µg mL^?1. Sensors were independent from the pH of test solutions within 4–7. Good selectivity was observed toward potassium, calcium, barium, magnesium, glycine, ascorbic acid, creatinine, norfloxacin, ciprofloxacin, and tetracycline. In flowing media, the biomimetic sensors presented good reproducibility (RSD of ± 0.7%), fast response, good sensitivity (47 mV/Δlog([ENR]/M), wide linear range (1.0 × 10^?5–1.0 × 10^?3 M), low detection limit (0.9 µg mL^?1), and a stable baseline for a 5 × 10^?2 M acetate buffer (pH 4.7) carrier. The sensors were used to analyze fish samples. The method offered the advantages of simplicity, accuracy, and automation feasibility. The sensing membrane may contribute to the development of small devices allowing in vivo measurements of enrofloxacin or parent-drugs.     

Improvement on Analyte Extraction by Molecularly Imprinted Polymer Microspheres toward Enrofloxacin

Abstract

A collection of molecularly imprinted polymer microspheres (MIPMs) for Enrofloxacin (ENRO) were for the first time obtained through suspension polymerization in this work. The appropriate MIPMs used as specific SPE adsorbents were selected based on evaluation of binding capacities and morphology characterization. Combined with one simpler MISPE procedure for cleanup and preconcentration of ENRO in milk, further HPLC-UV analysis showed improved sensitivity of 10 µg kg^?1 than those reported in previous studies, with the desirable recoveries of 73.6–101.6%, proving that the developed MIPMs are applicable for extraction of ENRO during the process of sample preparation.